• Advanced Photonics
  • Vol. 3, Issue 3, 034002 (2021)
Zhiping Hu1, Zhengzheng Liu2, Zijun Zhan1, Tongchao Shi2, Juan Du1、2、*, Xiaosheng Tang3、4、*, and Yuxin Leng1、2、*
Author Affiliations
  • 1University of Chinese Academy of Sciences, Hangzhou Institute for Advanced Study, Hangzhou, China
  • 2Chinese Academy of Sciences, Shanghai Institute of Optics and Fine Mechanics, State Key Laboratory of High Field Laser Physics and CAS Center for Excellence in Ultra-Intense Laser Science, Shanghai, China
  • 3Chongqing University of Posts and Telecommunications, School of Optoelectronic Engineering, Chongqing, China
  • 4Zhengzhou University, School of Materials Science and Engineering, Zhengzhou, China
  • show less
    DOI: 10.1117/1.AP.3.3.034002 Cite this Article Set citation alerts
    Zhiping Hu, Zhengzheng Liu, Zijun Zhan, Tongchao Shi, Juan Du, Xiaosheng Tang, Yuxin Leng. Advances in metal halide perovskite lasers: synthetic strategies, morphology control, and lasing emission[J]. Advanced Photonics, 2021, 3(3): 034002 Copy Citation Text show less

    Abstract

    In the past decade, lead halide perovskites have emerged as potential optoelectronic materials in the fields of light-emitting diode, solar cell, photodetector, and laser, due to their low-cost synthesis method, tunable bandgap, high quantum yield, large absorption, gain coefficient, and low trap-state densities. In this review, we present a comprehensive discussion of lead halide perovskite applications, with an emphasis on recent advances in synthetic strategies, morphology control, and lasing performance. In particular, the synthetic strategies of solution and vapor progress and the morphology control of perovskite nanocrystals are reviewed. Furthermore, we systematically discuss the latest development of perovskite laser with various fundamental performances, which are highly dependent on the dimension and size of nanocrystals. Finally, considering current challenges and perspectives on the development of lead halide perovskite nanocrystals, we provide an outlook on achieving high-quality lead perovskite lasers and expanding their practical applications.

    1 Introduction

    Research related to perovskites can be traced back to 1970s,13 but systematic research was lacking due to technology limitations in that period. In 2009, Kojima et al.4 first added organic–inorganic hybrid perovskites as semiconductor materials in dye-sensitized solar cells, achieving a power conversion efficiency (PCE) of 3.8%. Since that breakthrough, the development of perovskites with large absorption coefficient, low defect state density, long carrier diffusion length, and bipolar carrier transport property has made them uniquely suitable for photovoltaic applications.416 Currently, the PCE of single-junction pure perovskite-based solar cells has reached 25.5% for small-area devices and 24.2% for large area over 1  cm2.15,17 According to the Shockley–Queisser limit, a type of high-quality conversion material in solar cells is also efficient luminescent materials in light-emitting devices such as LEDs and lasers.1820 In 2004, the first evidence of optical gain in lead halide perovskites was reported, which is amplified spontaneous emission (ASE) from microcrystalline films of CsPbCl3 recrystallized from the amorphous phase.21,22 In 2014, ASE and lasing were realized from MAPbX3 polycrystalline thin films at room temperature. Ultralow threshold could benefit from the excellent optical absorption of MAPbX3 with a coefficient greater than 2×104  cm1.2327

    In addition, the research about micro/nanolasers based on perovskite with high coherence, low threshold, and high-quality factor has increased rapidly. The advances in lasing performance mainly benefit from the excellent optical properties such as high photoluminescence quantum yield (PLQY), narrow linewidth, large absorption coefficient, and widely tuned band.2832 In addition, the shape and size of perovskite could be flexibly adjusted, which can affect their physical and chemical properties and the performance of optoelectrical devices.3336 Hence, various synthesis strategies about the fabrication, control of morphologies, and sizes of perovskite nanocrystals (NCs) have been developed. The size can be adjusted from several nanometers to microns, and the morphologies can be controlled as zero-dimension (0D) quantum dots (QDs), one-dimensional (1D) nanorods (NRs) and nanowires (NWs), two-dimensional (2D) nanoplates (NPs) and nanosheets (NSs), and three-dimensional (3D) nanocubes and microspheres (MSs).3742 In this review, we discuss and summarize the recent developments in lead halide perovskite materials and perovskite-based lasers. In particular, the synthetic strategies of the perovskite containing solution process and vapor evaporation method are reviewed. Moreover, the morphology control of perovskite with various dimensions for the natural resonant cavities of lasing is discussed. Based on the perovskite QDs, NWs, NRs, NPs, and MSs, the single perovskite nano/microlaser and laser array are reviewed, and the dependence of laser performance on structure morphology is discussed. Finally, we present a summary and the perspectives of future research in the perovskite-based laser.

    2 Morphology Control of Perovskite NCs

    2.1 Structure of Perovskite

    As a kind of chemical material with an ABX3-type structure [Fig. 1(a)], the crystal structure of perovskite is the same as calcium titanate (CaTiO3).43 “A” could be an organic molecular group such as methylamino (MA) or an inorganic element such as cesium (Cs); “B” is generally a metal ion, such as lead (Pb), tin (Sn), and bismuth (Bi); “X” refers to a halide ion containing Cl, Br, and I. The tolerance factor (t) is generally used to evaluate the structural formability and stability, calculated as t=(rA+rX)/2(rB+rX), where rA, rB, and rX are ionic radii of A, B, and X sites, respectively. Li et al.45 introduced the “octahedral factor” (μ) to investigate the regularities of formability for cubic perovskite ABX3, which was defined as μ=rB/rX and suggested the formation of the halide perovskites under the conditions of 0.813<t<1.107 and 0.377<μ<0.895. Then, Sun et al. introduced (t+μ)η to evaluate the thermodynamic stability of hailde perovskite, where η is the atomic packing fraction in a crystal structure. By calculating decomposition energies of 138 perovskite compounds [Fig. 1(b)], they demonstrated better accuracy of (t+μ)η than the evaluation of t and μ alone.44,46

    (a) Structural model of metal lead perovskites. Figures reproduced from Ref. 43. (b) The (t,μ) map for 138 perovskite compounds. Figures reproduced from Ref. 44. (c) Nanoscale morphologies of halide perovskites.

    Figure 1.(a) Structural model of metal lead perovskites. Figures reproduced from Ref. 43. (b) The (t,μ) map for 138 perovskite compounds. Figures reproduced from Ref. 44. (c) Nanoscale morphologies of halide perovskites.

    2.2 Perovskite Quantum Dots

    Based on the ABX3 halide perovskites, the morphologies can be controlled with different dimensional nanostructures, such as 0D QDs, 1D NWs, 2D NPs, and 3D MSs.37,40,4765 Since different nanostructures will result in variable structure–property relationships at the nanoscale level, various strategies have been reported for controlling the form and size of the perovskite NCs, including changing the reaction temperature, the reaction time, and the ligand combinations during synthesis.3742 In addition, capping ligands with different structures and lengths can also affect the nucleation and growth rate, hence the structure of perovskite NCs can be adjusted owing to their anchoring and steric effects.4749

    As is well known, traditional semiconductor QDs have a quantum size effect. In the case of perovskite QDs, the bandgap can also be tuned via halide component regulation.3842,51 Zhang et al.25 developed a ligand-assisted reprecipitation (LARP) method to fabricate MAPbBr3 QDs at room temperature. Their PLQYs were up to 70% [Fig. 2(a)]. By mixing PbX2 salts into the precursors, the authors tuned emission in the range of 407 to 734 nm [Figs. 2(c) and 2(d)].25 In the case of all-inorganic ones, the emission spectra of CsPbX3 QDs fabricated by the high temperature method could be tunable over 410 to 700 nm with narrow half maximum of 12 to 42 nm and radiative lifetime of 1 to 29 ns [Figs. 2(e) and 2(f)].42 Subsequently, they proposed an anion-exchange process to tune the emission of colloidal CsPbX3 QDs via postsynthetic reactions with different compounds [Figs. 2(g) and 2(h)].41 Besides the hot-injection technique, the room-temperature synthesis for perovskite QDs was also studied.39 In 2016, Zeng and coworkers developed a room-temperature method to fabricate CsPbX3 QDs via supersaturated recrystallization. In this process, the crystallization process occurred in the transform of Cs+, Pb2+, and X ions from soluble to insoluble solvents in the absence of inert gas within a few seconds, as shown in Figs. 2(i) and 2(j).39 Although crystallized at room temperature, these CsPbX3 QDs held superior optical properties with PLQYs above 70%, and PLs can remain at 90% after aging 30 days in the air. Except for being regulated by changing composition, the bandgap of perovskite QDs also can be tuned by the size regulation of QDs. Chen et al.66 fabricated CsPbBr3 QDs with an average diameter from 7.1 to 12.3 nm by modifying the temperature, and the corresponding PL emission peaks could be tuned from 493 to 531 nm. Fang et al.67 synthesized MAPbBr3 QDs with tunable average diameter from 2.82 to 5.29 nm by varying the additive amount of surfactant, and the corresponding PL emission peaks could shift from 436 to 520 nm due to the quantum confinement effect. Most recently, there have been much more researches about perovskite QDs by composition engineering for wider optoelectronic applications.6870

    (a) Schematic of LARP technique. Figures reproduced from Ref. 25. (b) Schematic of precursor and optical image of MAPbBr3 solution. Figures reproduced from Ref. 25. (c) Optical images of MAPbX3 solution under natural light and under 365 nm excitation. Figures reproduced from Ref. 25. (d) PL spectra of MAPbX3 QDs. Figures reproduced from Ref. 25. (e) PL optical images and PL spectra of CsPbX3 QDs. Figures reproduced from Ref. 42. (f) Time-resolved PL decays for CsPbX3 QDs. Figures reproduced from Ref. 42. (g) Schematic of the anion-exchange of CsPbX3. Figures reproduced from Ref. 41. (h) TEM images of CsPbX3 QDs with various PL. Figures reproduced from Ref. 41. (i) Schematic of room-temperature fabrication of CsPbX3 QDs. Figures reproduced from Ref. 39. (j) Optical images of CsPbX3 QDs after the addition of precursor ion solutions for 3 s. Figures reproduced from Ref. 39.

    Figure 2.(a) Schematic of LARP technique. Figures reproduced from Ref. 25. (b) Schematic of precursor and optical image of MAPbBr3 solution. Figures reproduced from Ref. 25. (c) Optical images of MAPbX3 solution under natural light and under 365 nm excitation. Figures reproduced from Ref. 25. (d) PL spectra of MAPbX3 QDs. Figures reproduced from Ref. 25. (e) PL optical images and PL spectra of CsPbX3 QDs. Figures reproduced from Ref. 42. (f) Time-resolved PL decays for CsPbX3 QDs. Figures reproduced from Ref. 42. (g) Schematic of the anion-exchange of CsPbX3. Figures reproduced from Ref. 41. (h) TEM images of CsPbX3 QDs with various PL. Figures reproduced from Ref. 41. (i) Schematic of room-temperature fabrication of CsPbX3 QDs. Figures reproduced from Ref. 39. (j) Optical images of CsPbX3 QDs after the addition of precursor ion solutions for 3 s. Figures reproduced from Ref. 39.

    2.3 Perovskite Nanowires and Nanorods

    Perovskite 1D NWs and NRs are more applicable in the field of optoelectronic applications due to their special anisotropic structures. In the growth of 1D perovskite structures, reaction temperature, reaction time, and organic ligands are critical factors for crystallization.7174 Deng et al.71 first fabricated MAPbI3 NWs via the one-step solution method. In this process, the precursor solution containing PbI2 and CH3NH3I was dropped onto a substrate and then heated at different temperatures. Finally, uniform MAPbI3 NWs were obtained after heating at 80°C for 10 min. In 2017, they fabricated Csx(MA)1xPbI3 NWs through a two-step solution method.72 As shown in Fig. 3(a), PbI2 powder was dissolved in water at 75°C initially, then PbI2 separated out when the solution cooled down to room temperature. With the addition of CsI and MAI, perovskite NWs could be formed after shaking for a few seconds. The length and diameter of obtained perovskite NWs could reach 10  μm and several hundred nanometers. Moreover, the amount of perovskite NWs was related to the concentration of PbI2 separated out from aqueous solution.72 Zhu et al. developed a direct conversion of MAPbI3 film into NWs through a recrystallization process [Fig. 3(b)]. The first step was the formation of perovskite film from a mixture of PbCl2 and CH3NH3I.73 Then, a mixture solution containing DMF and isopropyl was dropped onto the as-grown perovskite film. Along with the evaporation of the solvent, NWs could be formed [Fig. 3(b)].73 Furthermore, they found the content of DMF in isopropyl, and the rotation speed could affect the sizes of prepared MAPbI3 NWs.

    (a) Schematic of the fabrication process for the Csx(CH3NH3)1−xPbI3 NWs. Figures reproduced from Ref. 72. (b) Schematic of the formation of the MAPbI3 NWs by recrystallization process. Figures reproduced from Ref. 73. (c) TEM images of as-grown CsPbBr3 NCs with increasing times. Figures reproduced from Ref. 51. (d) Absorption and PL spectra of CsPbBr3 NWs. Figures reproduced from Ref. 56. (e) Schematic of the passivation effect by HX on the length of CsPbX3 NWs and TEM images of the synthesized CsPbX3 NWs. Figures reproduced from Ref. 58. (f) Normalized absorption, PL spectra, and photographs of CsPbX3 NWs. Figures reproduced from Ref. 58.

    Figure 3.(a) Schematic of the fabrication process for the Csx(CH3NH3)1xPbI3 NWs. Figures reproduced from Ref. 72. (b) Schematic of the formation of the MAPbI3 NWs by recrystallization process. Figures reproduced from Ref. 73. (c) TEM images of as-grown CsPbBr3 NCs with increasing times. Figures reproduced from Ref. 51. (d) Absorption and PL spectra of CsPbBr3 NWs. Figures reproduced from Ref. 56. (e) Schematic of the passivation effect by HX on the length of CsPbX3 NWs and TEM images of the synthesized CsPbX3 NWs. Figures reproduced from Ref. 58. (f) Normalized absorption, PL spectra, and photographs of CsPbX3 NWs. Figures reproduced from Ref. 58.

    As for all-inorganic perovskite, in 2015, Yang and coworkers used a solution method to synthesize single-crystalline CsPbX3 NWs first. The reaction temperature was set as 150°C to 250°C.51 They found that the reaction time was critical to the growth of NWs. As shown in Fig. 3(c), the SEM of prepared CsPbBr3 with different reaction times showed perovskite nanocubes formed initially, then NS and NW formed at 90 min [Fig. 3(c)].51 In the formation of Cs-based perovskite NWs, surface ligands could affect the width and size. Imran et al.56 tuned the width of CsPbX3 NWs from 10 to 20 nm by regulating the ratio of octylamine to oleylamine and varying the reaction time. They found that the width of NWs can be decreased below 5  nm by introducing carboxylic acids with short aliphatic chains. Correspondingly, the emission spectra of CsPbBr3 NWs could be tuned from 524 to 473 nm [Fig. 3(d)].56 Amgar et al.58 found that various hydrohalic acids (HX, X = Cl, Br, and I) affect the length of CsPbBr3 NWs efficiently. With the increasing amount of HX, the length of NWs would be shortened [Fig. 3(e)]. Using this method, the emission of the CsPbBr3 NWs could be tunable in the range of 423 to 505 nm [Fig. 3(f)].58CsPbBr3 NWs/NRs can also be synthesized by a low-temperature method. Dong’s group74 fabricated CsPbBr3 perovskite NRs with controllable size in a polymer matrix. Then, Liu et al. fabricated single-crystalline CsPbBr3 NWs without inert gas at room temperature. By increasing the reaction time, the length of NWs could be increased from nanometers to micrometers, and the diameter could be tuned from 2.5 to 32.0 nm. Moreover, using this method, the emission spectra of CsPbX3 NWs could be tuned from 434 to 681 nm.57

    Besides the above-mentioned solution-process, plenty of works have been reported on synthesizing perovskite NWs and NRs by vapor-phase growth.49 More than ever, the vapor-phase process can control the morphology and crystalline phase of perovskite NCs efficiently. It has been demonstrated that the growth temperature and the substrates are critical for the orientation of perovskite NWs in vapor-growth. Xing et al.49 first used the vapor-phase technique to fabricate perovskite NWs. First, PbI2 NWs were deposited on SiO2 substrates by the chemical vapor deposition (CVD) method [Fig. 4(a)].49 Consequently, PbI2 was converted into MAPbX3 after the reaction with MAX through a CVD process. As shown in Fig. 4(b), the prepared MAPbI3 wires had a length about tens of micrometers and a diameter of 500  nm. In Figs. 4(c) and 4(d), they indicated that MAPbI3 NW grows along the [100] direction.49 Due to the thermal decomposition of organic hybrid perovskite occurring easily at high temperatures, direct vapor–phase growth of hybrid perovskites is more challenging. However, the vapor–phase technique is an attractive method for all-inorganic perovskites, which have better thermostability. Zhou et al.75 prepared CsPbX3 NRs with high crystallization quality and regular triangular morphology through a vapor deposition method [Fig. 4(e)]. As shown in the SEM image [Fig. 4(f)], prepared CsPbX3 NRs had a triangular cross section, smooth surfaces, and a length of 2 to 20  μm. They demonstrated that the reaction temperature was critical for the control of perovskite NCs during the growth of triangular CsPbBr3 NRs. Moreover, the emission of these as-grown CsPbX3 NRs also can be tuned from 415 to 673 nm by halide component regulation [Fig. 4(g)].75

    (a) SEM image of PbI2 NWs. Figures reproduced from Ref. 49. (b) Optical microscopy image of MAPbI3 NWs. Figures reproduced from Ref. 49. Structure simulation images of (c) PbI2 NW and (d) MAPbI3 NW. Figures reproduced from Ref. 49. (e) Schematic of the CsPbX3 triangular micro/NRs. Figures reproduced from Ref. 75. (f) SEM image of CsPbBr3 triangular rods. Figures reproduced from Ref. 75. (g) Real-color image and PL spectra of CsPbX3 triangular rods. Figures reproduced from Ref. 75. (h), (i) SEM images of the CsPbBr3 NWs. Figures reproduced from Ref. 62.

    Figure 4.(a) SEM image of PbI2 NWs. Figures reproduced from Ref. 49. (b) Optical microscopy image of MAPbI3 NWs. Figures reproduced from Ref. 49. Structure simulation images of (c) PbI2 NW and (d) MAPbI3 NW. Figures reproduced from Ref. 49. (e) Schematic of the CsPbX3 triangular micro/NRs. Figures reproduced from Ref. 75. (f) SEM image of CsPbBr3 triangular rods. Figures reproduced from Ref. 75. (g) Real-color image and PL spectra of CsPbX3 triangular rods. Figures reproduced from Ref. 75. (h), (i) SEM images of the CsPbBr3 NWs. Figures reproduced from Ref. 62.

    In addition, it has been confirmed that the substrate can affect the grain orientation growth of perovskite NWs.76 Chen et al.62 fabricated CsPbX3 wires on mica by the CVD method. During the growth of CsPbBr3 NWs, heteroepitaxial matching occurred in the interface between CsPbBr3 NCs and mica substrate. Then, the formation of NWs was caused by the asymmetric lattice mismatch with the mica substrate. As shown in Figs. 4(h) and 4(i), the obtained CsPbBr3 wires were well-aligned, surface-bound, and formed a network with a length about tens of μm and width of 1  μm, respectively.62 Moreover, various nanostructures could be formed by controlling the deposition time, such as single NWs, Y-shaped branches, and interconnected NW or MW networks.62

    2.4 2D Metal Halide Perovskite Nano/Microstructures

    2.4.1 Perovskite nano/microplates

    The unique and excellent properties of 2D structured perovskite such as NSs, NPs, and microdisks (MDs) make them promising for potential optoelectronic devices.77 Sichert et al.61 synthesized MAPbBr3 NPs and investigated the quantum size effect of NPs via the solution method. They found that the thickness of MAPbBr3 NPs was reduced with the increase of the content of OA [Figs. 5(a) and 5(b)]. Correspondingly, the PL emission was tuned from the green to violet region [Fig. 5(c)].61 Qin et al. prepared MAPbI3 NPs via a two-step solution method. First, PbI2/DMF solvent was spin-coated onto a substrate to form PbI2 thin films. Then, the formed PbI2 thin film was immersed into MAI solution, in which MAPbI3 single NCs were formed.81

    (a) Schematic of the synthesis of MAPbBr3 NPs. Figures reproduced from Ref. 61. (b) Quantum size effect in MAPbBr3 NPs. Figures reproduced from Ref. 61. (c) Bandgap tuning in MAPbBr3 NPs and micro/NRs via size or compositional control. Figures reproduced from Ref. 61. (d) PL spectra of the halide–anion exchanged CsPbX3 NPs. Figures reproduced from Ref. 37. (e) 2D CsPbBr3 NSs. Figures reproduced from Ref. 37. (f) SEM images of CsPb2Br5 MP. Figures reproduced from Ref. 78. (g) Top: Schematic of the growth of 2D CsPbX3 NPs and NSs from CsPbX3 NRs. Bottom: TEM images of CsPbBr3 NCs for different times. Figures reproduced from Ref. 79. (h) Schematic of the fabrication of MAPbI3 NCs using a vapor-transport system. Figures reproduced from Ref. 80. (i) Thickness of PbI2 platelets before and after being converted to MAPbI3. Figures reproduced from Ref. 80. (j) Optical images of as-grown MAPbI3 NCs with different temperature and pressure. Figures reproduced from Ref. 64.

    Figure 5.(a) Schematic of the synthesis of MAPbBr3 NPs. Figures reproduced from Ref. 61. (b) Quantum size effect in MAPbBr3 NPs. Figures reproduced from Ref. 61. (c) Bandgap tuning in MAPbBr3 NPs and micro/NRs via size or compositional control. Figures reproduced from Ref. 61. (d) PL spectra of the halide–anion exchanged CsPbX3 NPs. Figures reproduced from Ref. 37. (e) 2D CsPbBr3 NSs. Figures reproduced from Ref. 37. (f) SEM images of CsPb2Br5 MP. Figures reproduced from Ref. 78. (g) Top: Schematic of the growth of 2D CsPbX3 NPs and NSs from CsPbX3 NRs. Bottom: TEM images of CsPbBr3 NCs for different times. Figures reproduced from Ref. 79. (h) Schematic of the fabrication of MAPbI3 NCs using a vapor-transport system. Figures reproduced from Ref. 80. (i) Thickness of PbI2 platelets before and after being converted to MAPbI3. Figures reproduced from Ref. 80. (j) Optical images of as-grown MAPbI3 NCs with different temperature and pressure. Figures reproduced from Ref. 64.

    CsPbBr3 NPs were prepared by Bekenstein et al.37 through a hot-injection method. They demonstrated that the reaction temperature is critical for the shape and thickness of CsPbBr3 NPs. As the temperature decreased from 150°C to 130°C, the shape of CsPbBr3 NCs evolved from nanocubes to NPs. Correspondingly, the PL emission was shifted from 512 to 405 nm [Figs. 5(d) and 5(e)].37 When the temperature decreased to 90°C and 100°C, the thin CsPbBr3 NPs were obtained with lengths of about 200 to 300 nm [Fig. 5(d)].37 Except for the reaction temperature, surface ligands also affect the formation of CsPbX3 NPs, which was demonstrated by Pan et al. in 2016. During the growth of NPs, CsPbX3 NPs were obtained at a relatively lower reaction temperature (120°C to 140°C). They obtained thinner CsPbX3 NPs with shorter chain amines.82 In addition, the reaction time was also found to be critical for the formation of perovskite NPs.78,79 By adding the PbBr2 concentration and increasing the reaction time above 1 h (135°C), a CsPb2Br5 microplate (MP) with a micrometer order size and regular end faces could be obtained [Fig. 5(f)].78 In 2018, Li et al. demonstrated that 2D CsPbX3 NPs and NSs can be obtained by varying the reaction time [Fig. 5(g)]. The thickness can be controlled in the range of 3 to 6 nm and the width in the range of 0.1 to 1  μm.79 Huang et al. reported a method for spontaneous crystallization of perovskite NCs in nonpolar organic solvent by mixing precursor ligand complexes without any heat treatment. By varying the ratio of monovalent to Pb2+ cation–ligand complexes, the shape of the NCs can be controlled from 3D nanocubes to 2D nanoplatelets.83

    Similar to the NWs, perovskite NPs can also be formed by the vapor synthesis method. Xiong and coworkers80 reported the CVD growth of MAPbI3 NPs. These NPs exhibited triangular or hexagonal platelet shapes, with thickness of 10 to 300 nm and lateral dimensions of 5 to 30  μm [Figs. 5(h) and 5(i)]. PbX2 platelets were first grown on mica via van der Waals epitaxy and then converted to MAPbX3 NPs with the existence of MAX. In 2016, Bao and coworkers developed a combined method containing a solution process and a vapor-phase conversion process to prepare MAPbI3 NSs. First, PbI2 flakes were dropped on a silica substrate and then heated. In this process, the temperature plays a crucial role in the nucleation and growth of 2D PbI2 NSs, since the amount of nucleation sites is controlled by temperature. Subsequently, MAPbI3 NSs were formed after the conversion reaction with MAI.84 During the vapor-phase growth, the growth pressure and temperature both could affect the formation of perovskite NCs. Liu et al.64 fabricated 2D MAPbBr3 platelets (001) via the CVD method. As shown in Fig. 5(j), the square-shaped platelets could not form, as the growth pressure and temperature were low. By increasing the pressure, 2D platelets and 3D spheres could be observed. The average thickness of MAPbBr3 platelets increased from 29 to 73 nm, and the lateral size increased from 6 to 10  μm with the pressure increasing from 140 to 200 Torr.64

    As for all-inorganic 2D perovskite NCs, Zeng and coworkers85 synthesized ultrathin CsPbBr3 NPs (thickness 148.8  nm) on a mica substrate by van der Waals epitaxy through heating the PbBr2 and CsBr mixture. Zheng et al.86 synthesized 2D CsPbI3 perovskite NSs with high quality, controllable morphology, and ultrathin thickness (6.0  nm) via a space-confined vapor-phase epitaxial growth. In 2020, Yang and coworkers developed a facile method to pattern CsPbX3 plate arrays with crystal size (200 nm to 1  μm) and spacing (2 to 20  μm). These plate arrays were confined by prepatterned hydrophobic/hydrophilic surfaces.65 The method can evade the restriction of lattice matching between perovskite and substrates, enabling a large-area growth of 2D perovskite NCs with excellent crystalline quality.85

    2.4.2 Metasurface

    A metasurface is a type of 2D optical element composed of units with subwavelength scale size, producing resonant coupling between electric and magnetic components of the incident electromagnetic fields.8791 Several functionalities were demonstrated on all-dielectric metasurfaces, such as optical encoding, optical wavefront molding, polarization beam splitter, and enhanced PL.9294 Perovskite-based metasurfaces demonstrated potential for nonlinear absorption and optical encoding.95 Metasurfce structures can be realized by nanopatterning thin film. Many conventional nanofabrication techniques have been used for the fabrication of perovskite metasurfaces, such as nanoimprinting, electron beam lithography (EBL), focused ion beam milling (FIB), and inductively coupled plasma etching (ICP).90,94,9698

    Gholipour et al.97 first used the FIB technique to fabricate MAPbI3 metasurfaces (thickness 200  nm), which consisted of nanogratings and nanoslit metamolecules. Moreover, they demonstrated that the emission and quality factor of the reflection resonances can be tuned by varying the grating period.97 Makarov et al.98 developed nanoimprinting technology for patterning CsαFAβMAγPb(IxBry)3 metasurfaces, enabling them to enhance their linear and nonlinear PL [Figs. 6(a)6(d)]. After the spin-coating of the perovskite film with thickness of 200  nm, nanoimprinting with nanopillar and nanostripe molds was performed on perovskite thin film to form metasurfaces. They demonstrated that these metasurfaces can enhance linear PL eight times and nonlinear PL 70 times.98 Jeong et al.94 presented a polymer-assisted nanoimprinting method for fabricating large-area CsPbX3 nanopatterns. As shown in Fig. 6(e), during their nanoimprinting process, a precursor solution was spin-coated on a substrate initially, and then the nanoimprinting mold was pressed on the precursor film with thermal treatment subsequently. Thus, CsPbX3 was crystallized within the confines of molds [Fig. 6(f)]. This method could be easily extended to large-area perovskite patterns on different substrates.94 In addition, Fan et al.90 used the EBL flowed ICP technique to prepare near-infrared MAPbBr3 perovskite metasurfaces [Fig. 6(g)]. Based on these metasurfaces, many types of nonlinear processes and enhanced PL could be observed [Fig. 6(h)].90 The authors presented the application of perovskite metasurfaces on optical encryption.90 The perovskite metasurface also can be used in optical phase control, which was confirmed by Zhang et al. in 2019. They also used the EBL flowed ICP technique to prepare MAPbX3 cut-wire metasurfaces on metal substrates [Figs. 6(i) and 6(j)].96 They found that these MAPbX3 metasurfaces can generate a full phase control from 0 to 2π and high-efficiency and broadband polarization. Finally, they proved the potential application in holographic images based on the unique property of perovskite metasurfaces.96

    (a) Perovskite metasurfaces with enhanced emission. Figures reproduced from Ref. 98. SEM images of perovskite with (b) nanostripe and (c) nanohole structures. Figures reproduced from Ref. 98. (d) Enhanced PL spectra from perovskite metasurfaces with different structures. Figures reproduced from Ref. 98. (e) Schematics of the polymer-assisted nanoimprinting process for perovskite nanopatterns. Figures reproduced from Ref. 94. (f) SEM images of various perovskite nanopatterns. Figures reproduced from Ref. 94. (g) SEM images of MAPbBr3 metasurface for nonlinear imaging. Figures reproduced from Ref. 90. (h) The nonlinear PL and linear PL images of MAPbBr3 metasurfaces. Figures reproduced from Ref. 90. (i) SEM image of MAPbBr3 metasurface. Figures reproduced from Ref. 96. (j) The field distributions of MAPbBr3 perovskite metasurface. Figures reproduced from Ref. 96.

    Figure 6.(a) Perovskite metasurfaces with enhanced emission. Figures reproduced from Ref. 98. SEM images of perovskite with (b) nanostripe and (c) nanohole structures. Figures reproduced from Ref. 98. (d) Enhanced PL spectra from perovskite metasurfaces with different structures. Figures reproduced from Ref. 98. (e) Schematics of the polymer-assisted nanoimprinting process for perovskite nanopatterns. Figures reproduced from Ref. 94. (f) SEM images of various perovskite nanopatterns. Figures reproduced from Ref. 94. (g) SEM images of MAPbBr3 metasurface for nonlinear imaging. Figures reproduced from Ref. 90. (h) The nonlinear PL and linear PL images of MAPbBr3 metasurfaces. Figures reproduced from Ref. 90. (i) SEM image of MAPbBr3 metasurface. Figures reproduced from Ref. 96. (j) The field distributions of MAPbBr3 perovskite metasurface. Figures reproduced from Ref. 96.

    2.5 3D Metal Halide Perovskite Nano/Microstructures

    Besides 1D and 2D structured-perovskite, perovskite-based 3D structures have also been investigated. In 2017, a two-step method for the fabrication of CsPbX3 microcubes with subwavelength size was developed by Hu et al.99 These CsPbX3 microcubes had a regular cube shape and smooth end faces, displaying tunable emission and excellent structure stability for several months under ambient conditions. In the same year, Zhang and coworkers used the CVD method on the prepared CsPbX3 MSs with controlled diameter of 1  μm and tunable PL ranging from 425 to 715 nm [Figs. 7(a) and 7(b)].100 Wei et al.101 developed an automated microreactor system to fabricate an inorganic perovskite NCs sphere by UV photoinitiated polymerization in flow-focusing microfluidics [Figs. 7(c) and 7(d)]. These obtained CsPbBr3 spheres had a large diameter around 100  μm, and the diameter could be influenced by flow rates.101 Mi et al.102 used the CVD method to fabricate high-quality single MAPbBr3 crystals with a cube-corner pyramids shape and lateral dimension in the range of 2 to 10  μm on mica substrates [Fig. 7(e)]. Then, Yang et al.103 also used the CVD method to fabricate CsPbI3 triangular pyramids with a spontaneous emission of 719  nm at room temperature on a Si/SiO2 substrate [Fig. 7(f)].

    (a) SEM image of the CsPbI3 MSs. Figures reproduced from Ref. 100. (b) PL spectra of CsPbCl3, CsPbBr3, and CsPbI3 MSs. Figures reproduced from Ref. 100. (c) Monodispersed CsPbBr3 spheres under the excitation of UV light. Figures reproduced from Ref. 101. (d) SEM image of the monodispersed CsPbBr3 spheres. Figures reproduced from Ref. 101. (e) SEM image of the MAPbBr3 triangular pyramids. Figures reproduced from Ref. 102. (f) SEM image of the CsPbI3 triangular pyramids on a Si/SiO2 substrate. Figures reproduced from Ref. 103. (g) SEM image and (h) schematic of the formation of CsPbX3 nanoflowers. Figures reproduced from Ref. 104. (i) Photograph (upper) and PL emission spectra (bottom) of CsPbX3 nanoflowers. Figures reproduced from Ref. 104. (j) Crystal growth of MAPbBr3 cuboids (top) and SEM images of MAPbBr3 perovskite under different reaction time (bottom). Figures reproduced from Ref. 105.

    Figure 7.(a) SEM image of the CsPbI3 MSs. Figures reproduced from Ref. 100. (b) PL spectra of CsPbCl3, CsPbBr3, and CsPbI3 MSs. Figures reproduced from Ref. 100. (c) Monodispersed CsPbBr3 spheres under the excitation of UV light. Figures reproduced from Ref. 101. (d) SEM image of the monodispersed CsPbBr3 spheres. Figures reproduced from Ref. 101. (e) SEM image of the MAPbBr3 triangular pyramids. Figures reproduced from Ref. 102. (f) SEM image of the CsPbI3 triangular pyramids on a Si/SiO2 substrate. Figures reproduced from Ref. 103. (g) SEM image and (h) schematic of the formation of CsPbX3 nanoflowers. Figures reproduced from Ref. 104. (i) Photograph (upper) and PL emission spectra (bottom) of CsPbX3 nanoflowers. Figures reproduced from Ref. 104. (j) Crystal growth of MAPbBr3 cuboids (top) and SEM images of MAPbBr3 perovskite under different reaction time (bottom). Figures reproduced from Ref. 105.

    Except for the regular morphologies, complex perovskite structures have also been investigated. Chen et al.104 used a seed-mediated solvothermal method to fabricate monodisperse CsPbX3 NCs with nanoflower morphology [in Figs. 7(g)7(i)]. Figure 7(h) shows the growth process of CsPbBr3 nanoflowers, which is formed by the structure transformation from Cs4PbBr6 to CsPbBr3. It is obtained that CsPbX3 dodecapods contained 12 well-defined branches, with a PLQY of about 50%. Moreover, the PL emission could be tuned from 415 to 685 nm. They prepared a white LED device based on using CsPbBr3 nanoflowers, exhibiting the 135% National Television System Committee (NTSC) standard.104 In 2019, Li et al. fabricated single crystal microcuboid-MAPbBr3 and multistep-MAPbBr3 NCs via the solvothermal method at 120°C. In this process, microcuboid-MAPbBr3 was formed initially, and then the center of the surface was etched after long-time reaction, inducing the formation of multisteps. By adjusting the reaction temperature and time, the morphology and size of microcuboid-MAPbBr3 [Fig. 7(j)] could be adjustable, with performing potential in perovskite nanolaser and other optoelectronic devices.105

    3 Perovskite-Based Laser

    3.1 Nonlinear Optical Properties

    Nonlinear optics describes the nonlinear state of the interaction between light and matter.106111 The researches on optical nonlinear materials are fundamental to nonlinear optics devices such as optical storage, optical switches, optical amplifiers, and lasers.112114 Due to the multiformity of physical and chemical properties, halide perovskites have been demonstrated as promising materials as nonlinear optics materials, which are related to the component and crystal structure of perovskite NCs.106

    In 2015, Sargent and coworkers investigated two-photon absorption in MAPbBr3 single crystals, under ultrashort pulses 800 nm excitation [Figs. 8(a)8(d)]. They observed two-photon PL around 572  nm with an absorption coefficient of 8.6±0.5  cmGW1 at 800 nm.117 Later, Heiko et al. performed temperature-dependent PL measurements on MAPbBr3 single crystals under 810 nm excitation. They observed obvious wavelength shifts of PLs with variable temperatures, which was attributed to discrete transitions between several stable crystalline phases of MAPbBr3 single crystals.115 In 2016, Kalanoor et al. studied the nonlinear optical responses of MAPbI3 films by the Z-scan technique, under nanosecond and femtosecond pulsed lasers. The nonlinear refractive index under femtosecond excitation was 69×1012 and 34.4×109  cm2/W for resonant nanosecond excitation, which was equivalent to conventional semiconductors.118 The Z-scan study of MAPbX3 (X = Cl, Br, I) perovskite film under the 800 nm, 40 fs pulse indicated that MAPbI3 films have a relatively large nonlinear optical coefficient compared with the MAPbCl3 and MAPbBr3 films.119 In the case of inorganic perovskites, Sun and coworkers discovered nonlinear optical properties of CsPbX3 NCs for the first time [Figs. 8(e)8(g)]. They observed strong two-photon absorption from 9-nm-sized CsPbBr3 NCs, with a large absorption cross-section of 1.2×105  GM.116 The nonlinear optical properties of CsPbX3 perovskite are highly correlated with their morphology. Jiang and coworkers120 investigated nonlinear optical properties of CsPbBr3 NSs with a dependence on their thickness. When the thickness of CsPbBr3 NS was adjusted from 104.6 to 195.4  nm, PL intensity increased nearly three times. They demonstrated that the two-photon absorption coefficient is inversely proportional to the thickness of CsPbBr3 NSs.120 Krishnakanth et al. investigated nonlinear optical properties from nanocubes and NRs by Z-scan technology, under femtosecond 600, 700, and 800 nm lasers. They obtained large two-photon absorption cross sections of 105 GM and strong nonlinear optical susceptibility of 1010  esu in these films.121

    (a) Absorption spectrum and normalized two-photon PL spectra of single MAPbBr3 NCs. Figures reproduced from Ref. 115. (b) Schematic of two-photon absorption at 800 nm in perovskite. Figures reproduced from Ref. 115. (c) Two-photon absorption coefficient. (d) Inverse transmission versus peak intensity for typical single MAPbBr3 NCs. Figures reproduced from Ref. 115. (e)–(g) Nonlinear optics of CsPbX3 NCs: (e) linear absorption spectrum and normalized PL spectra from CsPbBr3 NCs, (f) PL decay of CsPbBr3 NCs, and (g) Z-scan responses of the CsPbBr3 NC solution and the pure solvent. Figures reproduced from Ref. 116.

    Figure 8.(a) Absorption spectrum and normalized two-photon PL spectra of single MAPbBr3 NCs. Figures reproduced from Ref. 115. (b) Schematic of two-photon absorption at 800 nm in perovskite. Figures reproduced from Ref. 115. (c) Two-photon absorption coefficient. (d) Inverse transmission versus peak intensity for typical single MAPbBr3 NCs. Figures reproduced from Ref. 115. (e)–(g) Nonlinear optics of CsPbX3 NCs: (e) linear absorption spectrum and normalized PL spectra from CsPbBr3 NCs, (f) PL decay of CsPbBr3 NCs, and (g) Z-scan responses of the CsPbBr3 NC solution and the pure solvent. Figures reproduced from Ref. 116.

    The laser is a process of amplifying optical signals and generating high-intensity coherent light through stimulated radiation and is usually composed of three parts: energy pumping source, gain medium, and optical resonator. The amplification of the laser can be quantified as the resonance ability of gain media.122,123 For gain media, the optical gain of the semiconductor is similar to the optical absorption, which is suitable for perovskite.124,125 At the same time, optical losses are generated in optical cavities, which mainly come from nonradiative recombination, phonon scattering, edge scattering, and field leakage in the interface of cavities.126 Perovskite materials have ultralow density, inducing high optical gain and low optical losses for resonance in perovskite, enabling promising potential in perovskite lasers with low threshold. The optical gain of semiconductors can be calculated by the variable-stripe-length measurement, which is related to the dependence of the amplified luminescence on the length of the slit width of the excitation. Xing et al.23,124 performed variable stripe length measurements on MAPbI3 with a gain coefficient of 250  cm1, which was close to that of conventional semiconductor materials. The obtained optical gain coefficients of MAPbBr3 and MAPbCl3 were 300 and 110  cm1, respectively.127,128 Liu et al.129 demonstrated that the optical gain coefficient of CsPbBr3 nanocuboids can be calculated to be 502  cm1 under the 800 nm laser. Then, Zhao et al. reported efficient two-photon ASE from CsPbBr3 single crystals with a millimeter size and an optical gain of 38  cm1.130

    3.2 Perovskite QDs Laser

    In the case of perovskite QDs without an external cavity, the amplification was generated from multiple scattering between QDs, enabling random fluctuations of lasing modes.127 In 2015, Kovalenko and coworkers reported low-threshold ASE from colloidal CsPbX3 NCs with an optical gain coefficient of 450  cm1 and threshold of 5  μJ/cm2.127 In Figs. 9(a)9(c), the ASE from CsPbX3 NCs could be tuned from 440 to 700 nm. Finally, they obtained random lasing from CsPbX3 films without the resonant cavity and whispering gallery mode (WGM) lasing using a silica sphere as the resonant cavity [Fig. 9(c)].127 Besides, coating perovskite QDs onto an external cavity, Zeng and coworkers developed another method to form resonant cavities for perovskite QDs. They obtained enhanced random lasing from strong scattering in the perovskite/SiO2 composite with low threshold of 40  μJ/cm2 [Figs. 9(d)9(f)].131 Similarly, Yang et al.136 realized upconversion random lasing from FAPbBr3/A-SiO2 composites with a threshold of 413.7  μJ/cm2. Liu et al.137 obtained WGM and random lasing with a threshold of 430  μJ/cm2 under 800 nm excitation by embedding CsPbBr3 QDs into a single silica sphere. In addition, microcapillary tubes can also be used to build WGM cavities for perovskite QDs. In 2015, Zeng and coworkers observed lasing emission from CsPbBr3 QDs by filling the CsPbBr3 QDs into a capillary tube, which acted as a WGM cavity for perovskite QDs film around the inner wall.138 Later, stable two-photon pumped WGM lasing was realized by coupling CsPbBr3 and FAPbBr3 perovskite QDs into microtubules with thresholds of 0.8 and 0.31  mJ/cm2 [Figs. 9(g)9(j)], respectively.132,139

    (a) TEM images of CsPbBr3 QDs. Figures reproduced from Ref. 127. (b) Spectral tunability of ASE of CsPbX3 via compositional modulation. Figures reproduced from Ref. 127. (c) Evolution from PL to lasing in an MS resonator with increasing pump intensity. Figures reproduced from Ref. 127. (d) SEM image and (e) isolation effect of CsPbBr3QDs/A-SiO2 composites. Figures reproduced from Ref. 131. (f) PL spectra from CsPbBr3QDs/A-SiO2 composite with increasing pump intensity. Figures reproduced from Ref. 131. (g) TEM image of FAPbBr3 QDs. (h) Two-photon PL spectra from FAPbBr3 NCs in a microcapillary tube. (i) Optical image and (j) lasing emission spectra from FAPbBr3 NCs in a microcapillary tube. Figures reproduced from Ref. 132. (k) Left: PL spectra from CsPbBr3 film within/without microcavity. Right: Schematic of the CsPbBr3 VCSEL. Figures reproduced from Ref. 133. (l) Schematic of the CsPbBr3 VCSEL. Figures reproduced from Ref. 134. (m) Photograph and PL stability of flexible FAPbBr3 VCSEL. Figures reproduced from Ref. 135.

    Figure 9.(a) TEM images of CsPbBr3 QDs. Figures reproduced from Ref. 127. (b) Spectral tunability of ASE of CsPbX3 via compositional modulation. Figures reproduced from Ref. 127. (c) Evolution from PL to lasing in an MS resonator with increasing pump intensity. Figures reproduced from Ref. 127. (d) SEM image and (e) isolation effect of CsPbBr3QDs/A-SiO2 composites. Figures reproduced from Ref. 131. (f) PL spectra from CsPbBr3QDs/A-SiO2 composite with increasing pump intensity. Figures reproduced from Ref. 131. (g) TEM image of FAPbBr3 QDs. (h) Two-photon PL spectra from FAPbBr3 NCs in a microcapillary tube. (i) Optical image and (j) lasing emission spectra from FAPbBr3 NCs in a microcapillary tube. Figures reproduced from Ref. 132. (k) Left: PL spectra from CsPbBr3 film within/without microcavity. Right: Schematic of the CsPbBr3 VCSEL. Figures reproduced from Ref. 133. (l) Schematic of the CsPbBr3 VCSEL. Figures reproduced from Ref. 134. (m) Photograph and PL stability of flexible FAPbBr3 VCSEL. Figures reproduced from Ref. 135.

    Besides the realization of perovskite QDs lasing-based silica sphere and microcapillary tube, the well-designed distributed Bragg reflector (DBR) can also be used to achieve a vertical-cavity surface-emitting laser (VCSEL).133135 In 2017, Zeng and coworkers first fabricated VCSELs with a sandwiched structure of DBR/CsPbBr3 QDs/DBR, which exhibited a low threshold 9  μJ/cm2 directional output and favorable stability [Fig. 9(k)].133 The lasing emission of CsPbX3-based VCSELs can be tuned in the visible light range.133 In the same year, Huang et al.134 fabricated CsPbBr3 QDs VECSLs with ultralow threshold of 0.39  μJ/cm2 [Fig. 9(l)]. Organic hybrid perovskites-based VCSELs have also been performed. Chen and Nurmikko135 developed FAPbBr3-based VCSELs by embedding FAPbBr3 solid thin films in two DBRs [Fig. 9(m)] with a threshold of 18.3  μJ/cm2 under subnanosecond pulse excitations. They also demonstrated that the VCSEL device fabrication process can be applicable to flexile substrates, as shown in Fig. 9(m), which extended further practical applications for perovskite-based laser devices.135 Most recently, Li et al.140 fabricated a two-photon-pumped MAPbBr3 VCSEL by intergrading MAPbBr3 with DBR and Ag mirrors with a threshold of 421  μJ/cm2, a Q factor of 1286, and a small divergence of 0.5  deg.

    3.3 Perovskite Nanowire/Nanorod Laser

    Owing to the difference between the refractive index of perovskite material and air, the reflection can occur at the output interface easily, acting as optical reflector.141,142 Hence, different from QDs, single perovskite crystals structures such as rods, wires, plates, cubes, and spheres can act as Fabry–Pérot (F-P) or WGM cavities by themselves, since the light can be confined in the resonant cavity with regular morphology and smooth end faces.125 For the 1D NWs structure, light will propagate along 1D and form resonance between two end-facets.143 Hence, perovskite NWs and NRs have been confirmed as potential structures in optoelectronic devices and nanoscale-integrated photonics due to their unique optical properties, such as highly coherent output and efficient waveguide effect.143

    Zhu et al.144 demonstrated perovskite NW lasers using high-quality MAPbX3 NWs, which had a regular shape with rectangular cross section [Fig. 10(a)]. Tunable F-P lasing could be observed from single MAPbX3 NWs with low threshold of 0.22  μJ/cm2 and Q factor of 3600 at room temperature [Figs. 10(b) and 10(c)]. In the same year, Xing et al.49 realized F-P lasing from MAPbI3 NWs with rectangular morphology and length of 20  μm. The obtained NW laser exhibited low threshold of 11  μJ/cm2 and Q factor of 405, and the lasing wavelength could be tuned in the range of 551 to 777 nm.49 In case of lasing from all-inorganic perovskite NWs, Yang and coworkers realized F-P lasing from CsPbBr3 NWs with a threshold of 5  μJ/cm2 and a Q factor of 1009.55 Fu et al. realized wavelength widely tunable F-P lasing from CsPbX3 NWs. The lasing wavelength could be tuned in the visible spectral region from 420 to 710 nm [Figs. 10(e)10(g)].145 In 2017, lasing emission from triangular CsPbX3 micro/NRs with an ultrasmooth surface by the vapor-phase approach was reported. The obtained lasing could be tuned in the range from 428 to 628 nm, with low threshold of 14.1  μJ/cm2 and high Q factor of 3500.75 Efficient multiphoton pumped lasing in a wide excitation wavelength range (700 to 1400 nm) was realized.147 Most of the single perovskite NWs mainly exhibited single-band lasing emission. In 2020, Tang et al. fabricated a single CsPbCl33xBr3x alloy NW via a solid–solid anion-diffusion process. They realized continuous F-P lasing in single as-prepared NWs, which could be tuned from 480 to 525 nm [Figs. 10(i) and 10(j)].146

    (a) SEM of MAPbI3 nanostructures. Figures reproduced from Ref. 144. (b) Optical image of single MAPbI3 NW. Figures reproduced from Ref. 144. (c) PL spectra of MAPbI3 NW around the lasing threshold. Figures reproduced from Ref. 144. (d) Broad tunable lasing from single-crystal MAPbX3 NW. Figures reproduced from Ref. 144. (e) SEM image of CsPbBr3 nanostructures. Figures reproduced from Ref. 145. (f) Fluorescence images of red/green/blue CsPbX3 NWs above lasing threshold. Figures reproduced from Ref. 145. (g) Broad tunable lasing from single-crystal CsPbX3 NWs. Figures reproduced from Ref. 145. (h) The photograph and PL spectra of a single CsPbCl3−3xBr3x NW. Figures reproduced from Ref. 146. (i) The schematic of optically pumping lasing from a single CsPbCl3−3xBr3x NW. Figures reproduced from Ref. 146. (j) Typical lasing spectra from a single CsPbCl3−3xBr3x NW. Figures reproduced from Ref. 146.

    Figure 10.(a) SEM of MAPbI3 nanostructures. Figures reproduced from Ref. 144. (b) Optical image of single MAPbI3 NW. Figures reproduced from Ref. 144. (c) PL spectra of MAPbI3 NW around the lasing threshold. Figures reproduced from Ref. 144. (d) Broad tunable lasing from single-crystal MAPbX3 NW. Figures reproduced from Ref. 144. (e) SEM image of CsPbBr3 nanostructures. Figures reproduced from Ref. 145. (f) Fluorescence images of red/green/blue CsPbX3 NWs above lasing threshold. Figures reproduced from Ref. 145. (g) Broad tunable lasing from single-crystal CsPbX3 NWs. Figures reproduced from Ref. 145. (h) The photograph and PL spectra of a single CsPbCl33xBr3x NW. Figures reproduced from Ref. 146. (i) The schematic of optically pumping lasing from a single CsPbCl33xBr3x NW. Figures reproduced from Ref. 146. (j) Typical lasing spectra from a single CsPbCl33xBr3x NW. Figures reproduced from Ref. 146.

    3.4 Perovskite Nano/Microplate Laser

    Different from the F-P cavity formed by NWs/NRs, the perovskite 2D structure such as NPs will result in the WGM optical resonant cavity, which has a higher Q factor than the F-P cavity. In 2014, Zhang et al. first realized WGM lasing from MAPbI3 NPs with well-defined hexagonal and triangular shapes under femtosecond-pulsed laser excitation. The lasing wavelength was located at 780  nm with a threshold of 37  μJ/cm2 [Figs. 11(a)11(d)].80 Liao et al.150 obtained single-mode WGM lasing from single MAPbBr3 MDs peaked at 557.5  nm with a threshold of 3.6  μJ/cm2 and Q factor of 430. Liu et al. realized WGM lasing from MAPbI3 MP arrays with low threshold of 11  μJ/cm2 and Q factor of 1210.151 Moreover, they observed single mode lasing by shortening the size of MPs.151 Qi et al.152 demonstrated that the threshold of the MPs laser decreases linearly depending on the later size, and the cavity mode density increases with the size. In 2019, WGM lasing from a triangular MAPbI3 perovskite NP with a lateral length of 27  μm and thickness of 80 nm was realized at room temperature. The threshold of the WGM laser was 18.7  μJ/cm2 and Q factor was 2600 [Figs. 11(e)11(i)].148

    (a) Schematic of an MAPbX3 NP pumped by a pulsed laser. Figures reproduced from Ref. 80. (b) Optical image of MAPbI3 NPs under white light and laser excitation. Figures reproduced from Ref. 80. (c) Lasing spectra of hexagonal MAPbI3 NPs (upper) and the lasing mode evaluation with pumping fluence (bottom). Figures reproduced from Ref. 80. (d) Upper: Lasing spectra of triangular MAPbI3 NPs with different edge length. Bottom: The wavelength of lasing modes and Q-factor as a function of the triangular cavity edge length. Figures reproduced from Ref. 80. (e) Schematic of triangular MAPbI3 NPs pumped by a 343 nm laser. Figures reproduced from Ref. 148. (f) Optical image of triangular MAPbI3 NPs. Figures reproduced from Ref. 148. (g) 2D plot of a triangular MAPbI3 NP emission under different pump densities. Figures reproduced from Ref. 148. (h) The emission spectra from MAPbI3 NPs around the lasing threshold. Figures reproduced from Ref. 148. (i) Output emission intensity as a function of pump densities. Figures reproduced from Ref. 148. (j) Schematic of a CsPbX3 plate under a 400 nm laser. Figures reproduced from Ref. 149. (k) Emission spectra at different pump intensities. Figures reproduced from Ref. 149. (l) Tunable lasing spectra and images of individual CsPbX3 perovskite NPs. Figures reproduced from Ref. 149. (m) Single-mode lasing of CsPbBrxI3−x. Figures reproduced from Ref. 149. (n) Schematic of a CsPbI3 NS on mica substrate. Figures reproduced from Ref. 86. Excitation intensity-dependent emission spectra under (o) 470 nm and (p) 1200 nm excitation. Figures reproduced from Ref. 86. (q) Gaussian fitting of a lasing mode under 470 and 1200 nm laser. Figures reproduced from Ref. 86.

    Figure 11.(a) Schematic of an MAPbX3 NP pumped by a pulsed laser. Figures reproduced from Ref. 80. (b) Optical image of MAPbI3 NPs under white light and laser excitation. Figures reproduced from Ref. 80. (c) Lasing spectra of hexagonal MAPbI3 NPs (upper) and the lasing mode evaluation with pumping fluence (bottom). Figures reproduced from Ref. 80. (d) Upper: Lasing spectra of triangular MAPbI3 NPs with different edge length. Bottom: The wavelength of lasing modes and Q-factor as a function of the triangular cavity edge length. Figures reproduced from Ref. 80. (e) Schematic of triangular MAPbI3 NPs pumped by a 343 nm laser. Figures reproduced from Ref. 148. (f) Optical image of triangular MAPbI3 NPs. Figures reproduced from Ref. 148. (g) 2D plot of a triangular MAPbI3 NP emission under different pump densities. Figures reproduced from Ref. 148. (h) The emission spectra from MAPbI3 NPs around the lasing threshold. Figures reproduced from Ref. 148. (i) Output emission intensity as a function of pump densities. Figures reproduced from Ref. 148. (j) Schematic of a CsPbX3 plate under a 400 nm laser. Figures reproduced from Ref. 149. (k) Emission spectra at different pump intensities. Figures reproduced from Ref. 149. (l) Tunable lasing spectra and images of individual CsPbX3 perovskite NPs. Figures reproduced from Ref. 149. (m) Single-mode lasing of CsPbBrxI3x. Figures reproduced from Ref. 149. (n) Schematic of a CsPbI3 NS on mica substrate. Figures reproduced from Ref. 86. Excitation intensity-dependent emission spectra under (o) 470 nm and (p) 1200 nm excitation. Figures reproduced from Ref. 86. (q) Gaussian fitting of a lasing mode under 470 and 1200 nm laser. Figures reproduced from Ref. 86.

    As for the 2D all-inorganic perovskite-based laser, Zhang et al.149 obtained WGM excitonic lasing from single-crystalline CsPbX3 NPs with micron-size length and subwavelength thickness [Figs. 11(j)11(m)]. Multicolor lasing from 410 to 700 nm was realized in these NPs at room temperature [Fig. 11(l)]. The lasing threshold of the CsPbX3 NP was as low as 2.0  μJ/cm2, and the linewidth of the WGM modes was 0.14 to 0.15 nm [Fig. 11(m)].149 Zheng et al.86 demonstrated that CsPbI3 perovskite NSs possess WGM lasing under both one- and two-photon pumps with low-threshold-pumped excitation [Figs. 11(n)11(q)]. The thresholds of lasing were 0.30 and 2.6  mJ/cm2 under one- (470 nm) and two-photon (1200 nm) excitation, and the Q factors were 1489 and 1179, respectively, which is three times higher than the reported values of organic–inorganic lead halide perovskite NS. Most recently, Liu et al.153 realized two lasing modes (F-P and WGM) in the all-inorganic perovskite CsPb2Br5 MPs with subwavelength thickness and uniform square shape under two-photon pump. Remarkably, low-threshold F-P multimode lasing with Q factor of 3551 and single-mode WGM lasing with Q factor of 3374 from the same MP at room temperature have been achieved successfully.

    3.5 Perovskite Laser with 3D Structure

    A single perovskite spherical 3D structure has also usually been demonstrated as a WGM cavity. In comparison with other nano/microstructure resonant cavities, the coupling between the sphere cavity and substrate was relatively weak, which resulted in less optical losses. Zhang and coworkers realized single-mode lasing in CsPbX3 MSs with regular sphere shape and submicron size at room temperature [Figs. 12(a)12(d)].100 The line width of WGM lasing was 0.09  nm, the threshold was 0.42  μJ/cm2, and Q factor was 6100 [Fig. 12(c)]. In addition, the single-mode lasing can be tuned in the whole visible region through element modulation and size control of perovskite MSs [Fig. 12(d)].100 Furthermore, they achieved two-photon single-mode lasing with linewidth of 0.037  nm and Q factor of 1.5×104 from a single CsPbBr3 MS at room temperature, which are the best values obtained in perovskite-based micro/nanocavities until now.154 Moreover, these perovskite MS lasers showed uniform lasing emission, which could be observed in the range from 30  deg to 30 deg.154,155

    (a) Schematic of a single CsPbBr3 MS under 400 nm laser. Figures reproduced from Ref. 100. (b) Lasing PL spectra from a single CsPbBr3 MS under different pump intensities. Figures reproduced from Ref. 100. (c) Lorentzian fitting of a lasing mode. Figures reproduced from Ref. 100. (d) Photograph and lasing emission of multicolor CsPbX3 MS lasers. Figures reproduced from Ref. 100. (e) SEM image and (f) schematics of F-P cavity of CsPbBr3 nanocuboids. Figures reproduced from Ref. 129. (g) Single-mode lasing spectra and (h) TA spectroscopic data of CsPbBr3 nanocuboids under two-photon excitation. Figures reproduced from Ref. 129. (i) Schematic of a cube-corner MAPbBr3 pyramid under 405 nm laser. Figures reproduced from Ref. 102. (j) PL spectra of a cube-corner MAPbBr3 and (k) output intensity as a function of excitation power. Figures reproduced from Ref. 102. (l), (m) Multimode lasing spectra of a cube-corner pyramid of MAPbBr3 on (l) mica and (m) mica/Ag. Figures reproduced from Ref. 102.

    Figure 12.(a) Schematic of a single CsPbBr3 MS under 400 nm laser. Figures reproduced from Ref. 100. (b) Lasing PL spectra from a single CsPbBr3 MS under different pump intensities. Figures reproduced from Ref. 100. (c) Lorentzian fitting of a lasing mode. Figures reproduced from Ref. 100. (d) Photograph and lasing emission of multicolor CsPbX3 MS lasers. Figures reproduced from Ref. 100. (e) SEM image and (f) schematics of F-P cavity of CsPbBr3 nanocuboids. Figures reproduced from Ref. 129. (g) Single-mode lasing spectra and (h) TA spectroscopic data of CsPbBr3 nanocuboids under two-photon excitation. Figures reproduced from Ref. 129. (i) Schematic of a cube-corner MAPbBr3 pyramid under 405 nm laser. Figures reproduced from Ref. 102. (j) PL spectra of a cube-corner MAPbBr3 and (k) output intensity as a function of excitation power. Figures reproduced from Ref. 102. (l), (m) Multimode lasing spectra of a cube-corner pyramid of MAPbBr3 on (l) mica and (m) mica/Ag. Figures reproduced from Ref. 102.

    Another 3D structure generally used for perovskite lasing is the nano/microcube. Liu et al.129 obtained F-P lasers from an individual CsPbBr3 nanocuboid with subwavelength scale for the first time [Figs. 12(e)12(h)]. They realized single-mode F-P lasing from a CsPbBr3 nanocuboid with low thresholds of 40.2 and 374  μJ/cm2 and Q factors of 2075 and 1859 under one- and two-photon pumps, respectively.129 The physical volume of the obtained laser is 0.49λ3. Moreover, the pulse duration is only 22  ps, which is consistent with the resulting fast decay of SE observed by fs transient absorption spectroscopy [Fig. 12(h)].129 Cube-corner pyramid cavities could also act as microretroreflectors. In 2018, Mi et al. realized F-P lasing in cube-corner MAPbBr3 pyramids at room temperature [Figs. 12(i)12(m)].102 Furthermore, the threshold of lasing could be reduced from 92 to 26  μJ/cm2 by coating a thin layer of Ag film on a mica substrate [Figs. 12(l) and 12(m)].102 Most recently, Yang et al.103 also realized F-P lasing from a single CsPbI3 triangular pyramid with a microsize at low temperature. They demonstrated that the temperature-dependent lasing threshold can be reduced from 53.15 to 21.56  μJ/cm2 with corresponding temperature from 223 to 148 K.103

    3.6 Perovskite Nanolaser Array

    In comparison with single perovskite lasers, laser arrays with high-density patterns and high-precision arrangements are more necessary for mass-produced, compact on-chip optoelectronic circuit integration. In 2016, Wang et al. fabricated MAPbBr3 microwire arrays and realized high density perovskite lasers from these microwire arrays [Figs. 13(a) and 13(b)], in which all of the subunits generated the same lasing emission.156 The minimum unit period was 800 nm, presenting an integration density of nanolasers as high as 1250  mm1. In 2017, Fu and coworkers prepared MAPbBr3 NW arrays with the width from 460 to 2500 nm, height from 80 to 1000 nm, and length from 10 to 50  μm. These perovskite NW arrays were demonstrated as almost identical optical resonance cavities with a low threshold of 10.2  μJ/cm2 [Figs. 13(c) and 13(d)].157 In 2016, Liu et al. realized WGM lasing from patterned MAPBI3 microplatelets arrays with a threshold of 11  μJ/cm2 and Q factor up to 1210. The wavelength tunability and single mode lasing could be selected by changing platelet sizes or breaking the symmetry of the designed laser pattern.151 In the same year, Feng et al.158 demonstrated that the MAPbBr3 square MP array shows high-performance WGM lasing with tunable mode and low lasing threshold [Figs. 13(e) and 13(f)]. Single mode lasing was obtained from a 2.1-μmMAPbBr3 square. Lin et al.159 fabricated a large-area CsPbX3 QDs array by a photolithographical approach, which could be used as efficient lasing structures and emitting pixel arrays [Figs. 13(g)13(i)]. They realized WGM lasing from the QD arrays with high Q factor and demonstrated that this patterning technique can be used in large-area perovskite laser arrays with multicolor pixels [Fig. 13(g)].159 Most recently, Wang et al.160 fabricated large-area MAPbX3 MD arrays via a screen-printing technique [Figs. 13(j)13(m)]. They obtained tunable WGM lasing from these MAPbX3 MD arrays with a threshold of 21.3  μJ/cm2 and a Q factor of 1570 successfully. Multicolor WGM lasing emission could be tuned from 510 to 650 nm [Fig. 13(l)].160 In 2020, Song and coworkers employed the topologically protected optical bounded states in the continuum (BICs) and demonstrated the ultrafast control of perovskite-based vortex microlasers at room temperature. They proved that vortex beam lasing based on perovskite metasurfaces could be switched to linearly polarized beam lasing with switching time of 1 to 1.5 ps. The energy consumption was several orders of magnitude lower than that of previously reported all-optical switching.161

    (a) SEM image of the MAPbBr3 microwire on silicon grating. Figures reproduced from Ref. 156. (b) Laser spectrum of MAPbBr3 microwire. Figures reproduced from Ref. 156. (c) Optical image of MAPbBr3 NW arrays. Figures reproduced from Ref. 157. (d) PL spectra of a single MAPbBr3 NW under 400 nm laser. Figures reproduced from Ref. 157. (e) “LASER” patterned perovskite square MPs. Figures reproduced from Ref. 158. (f) Lasing spectra from perovskite MPs with different sizes. Figures reproduced from Ref. 158. (g) PL image of green and red QD arrays. Figures reproduced from Ref. 159. (h) Emission intensity versus excitation fluence measured from a CsPbBr3 MD. Figures reproduced from Ref. 159. (i) Lasing spectra from CsPbBr3 MDs with different diameters. Figures reproduced from Ref. 159. (j) PL spectra from a typical MAPbBr3 MD with different power energies and (k) output intensity and FWHM as a function of pump intensity. Figures reproduced from Ref. 160. (l) Widely tunable lasing from MAPbX3 arrays. Figures reproduced from Ref. 160. (m) Left: SEM image of the fabricated perovskite metasurface; right: ultrafast control of the quasi-BIC microlasers. Figures reproduced from Ref. 161.

    Figure 13.(a) SEM image of the MAPbBr3 microwire on silicon grating. Figures reproduced from Ref. 156. (b) Laser spectrum of MAPbBr3 microwire. Figures reproduced from Ref. 156. (c) Optical image of MAPbBr3 NW arrays. Figures reproduced from Ref. 157. (d) PL spectra of a single MAPbBr3 NW under 400 nm laser. Figures reproduced from Ref. 157. (e) “LASER” patterned perovskite square MPs. Figures reproduced from Ref. 158. (f) Lasing spectra from perovskite MPs with different sizes. Figures reproduced from Ref. 158. (g) PL image of green and red QD arrays. Figures reproduced from Ref. 159. (h) Emission intensity versus excitation fluence measured from a CsPbBr3 MD. Figures reproduced from Ref. 159. (i) Lasing spectra from CsPbBr3 MDs with different diameters. Figures reproduced from Ref. 159. (j) PL spectra from a typical MAPbBr3 MD with different power energies and (k) output intensity and FWHM as a function of pump intensity. Figures reproduced from Ref. 160. (l) Widely tunable lasing from MAPbX3 arrays. Figures reproduced from Ref. 160. (m) Left: SEM image of the fabricated perovskite metasurface; right: ultrafast control of the quasi-BIC microlasers. Figures reproduced from Ref. 161.

    3.7 Others

    Surface-plasmon (SP) is an excited state with large enhancement of the electromagnetic field localized at the metal–dielectric interface, which provides confinement on the subwavelength scale, overcoming the diffraction limit of light.162 In perovskite micro/nanolasers, SPs have been demonstrated as an effective method to tailor the properties of lasers. In general, SPs could be generated by the metal layer, such as Au or Ag, and transfer along the semiconductor–metal interface. Kao et al.163 reduced the lasing threshold of perovskite by strong exciton–plasmon coupling between the Ag and perovskite films [Fig. 14(a)],163 in which the confined optical fields between Ag and perovskite films could be enhanced about 19.3 and 7.7 times in comparison with bare perovskites and perovskites coated by Ag thin film, respectively. In 2017, Wang et al. deposited Al nanoparticles onto the surface of CsPbBr3 perovskites. The lasing thresholds of CsPbBr3 perovskite microrods were significantly reduced by >20%, and the output intensities were significantly enhanced via the plasmonic resonances.172 In 2019, Wu et al. reported a method to enhance ASE performance of MAPbI3 films by adding Au NRs-doped PMMA on MA3PbI3 perovskite films. The ASE threshold was significantly reduced by 36%, and the output intensity increased by 13.9-fold with the plasmon resonance enhancement of Au NRs.173 Yang et al.174 also reduced the lasing threshold of CsPbBr3 perovskite nanocubes significantly by 33% via the surface plasmonic effect of Au nanoparticles. In 2021, single-mode upconversion plasmonic lasing from MAPbBr3 perovskite NCs was realized by Lu et al.,164 exhibiting low threshold 10  μJ/cm2 and small mode volume 0.06λ3 at 6 K, where TiN was used as a promising resonance adjustable plasmonic platform [Fig. 14(b)]. Hsieh et al.165 realized continuous-wave (CW) lasing from a single CsPbBr3 QD in a plasmonic gap-mode nanocavity with low threshold of 1.9  W/cm2 and small mode volume of 0.002λ3 [Fig. 14(c)]. Most recently, Li et al.166 proposed a hybrid nanocavity composed of CsPbBr3 nanoparticles and a thin Au film, which could realize optically controlled quantum size effect by the reversible phase transition from polycrystalline to monocrystalline [Fig. 14(d)]. These results demonstrated that SPs could not only modulate the performance of perovskite lasers but also can realize deep subdiffraction plasmonic lasers.

    (a) Field intensity distributions and schematic structure of Ag/PMMA/perovskite. Figures reproduced from Ref. 163. (b) Schematic and working process of plasmonic nanolaser of MAPbBr3/Al2O3/TiN. Figures reproduced from Ref. 164. (c) Schematic and calculated electric field distribution of plasmonic nanolaser based on CsPbBr3 QDs. Figures reproduced from Ref. 165. (d) Schematic of phase transition from polycrystalline to monocrystalline CsPbBr3 nanoparticles by adjusting the laser power and the PL spectrum under different laser power. Figures reproduced from Ref. 166. (e) Schematic polaritons in a micro/NW cavity and lasing spectrum of CsPbBr3 NWs. Figures reproduced from Ref. 167. (f) Schematic of CW lasing of CsPbBr3 nanoribbons. Figures reproduced from Ref. 168. (g) Schematic structure of CsPbBr3 flakes/DBR microcavity and SEM image of CsPbBr3 flakes. Figures reproduced from Ref. 169. (h) Cascade energy transfer in quasi-2D perovskite and tunable ASE from solution-processed (NMA)2(FA)Pb2BryI7−y films. Figures reproduced from Ref. 170. (i) Chemical structures of quasi-2D perovskite with different organic cations and CW lasing characteristics of quasi-2D perovskite films. Figures reproduced from Ref. 171.

    Figure 14.(a) Field intensity distributions and schematic structure of Ag/PMMA/perovskite. Figures reproduced from Ref. 163. (b) Schematic and working process of plasmonic nanolaser of MAPbBr3/Al2O3/TiN. Figures reproduced from Ref. 164. (c) Schematic and calculated electric field distribution of plasmonic nanolaser based on CsPbBr3 QDs. Figures reproduced from Ref. 165. (d) Schematic of phase transition from polycrystalline to monocrystalline CsPbBr3 nanoparticles by adjusting the laser power and the PL spectrum under different laser power. Figures reproduced from Ref. 166. (e) Schematic polaritons in a micro/NW cavity and lasing spectrum of CsPbBr3 NWs. Figures reproduced from Ref. 167. (f) Schematic of CW lasing of CsPbBr3 nanoribbons. Figures reproduced from Ref. 168. (g) Schematic structure of CsPbBr3 flakes/DBR microcavity and SEM image of CsPbBr3 flakes. Figures reproduced from Ref. 169. (h) Cascade energy transfer in quasi-2D perovskite and tunable ASE from solution-processed (NMA)2(FA)Pb2BryI7y films. Figures reproduced from Ref. 170. (i) Chemical structures of quasi-2D perovskite with different organic cations and CW lasing characteristics of quasi-2D perovskite films. Figures reproduced from Ref. 171.

    Perovskite is also an ideal candidate to realize a room temperature exciton polariton laser, which mainly results from the strong exciton–photon coupling between the gain media and nanocavity. In perovskite laser researches, room temperature exciton polaritons have been realized with various nanostructures.167,168,175,176 Perovskite NCs with self-assembled morphology can provide optical resonators due to the confinement of exciton–photon coupling. On the other hand, a planar optical cavity composed of two mirrors can be used as an F-P cavity conventionally. In 2018, Liu et al.167 observed strong exciton–photon coupling in single CsPbBr3 micro/NWs and MAPbBr3 micro/NWs, respectively [Fig. 14(e)]. Moreover, polariton lasing was realized at room temperature with exceptionally large vacuum Rabi splitting of 656 and 390 meV.167,175 Shang et al.176 proved light could propagate as an exciton–photon in CsPbBr3 NWs at room temperature, increasing optical absorption and emission in comparison with bulk crystals. They demonstrated that the decrease of CsPbBr3 dimensions could enhance the exciton–photon coupling strength, which increased the exciton fraction. Furthermore, they found that the increase of temperature could significantly decrease the exciton fraction of exciton–photons, causing high thresholds and restraining CW lasing above 100 K. They successfully realized CW-pumped lasing from CsPbBr3 nanoribbons by reducing the height to 120  nm on sapphires with low threshold of 0.13  kW/cm2 [Fig. 14(f)].168 Then, they coupled MAPbBr3 NWs with a hybrid plasmonic microcavity to enhance exciton–photon interaction.177 They observed a Rabi-splitting up to 564  meV in a hybrid perovskite/SiO2/Ag waveguide microcavity at room temperature. In 2017, Su et al.178 reported room-temperature polariton lasing based on an epitaxy-free all-inorganic CsPbCl3 nanoplatelet embedded in DBRs, supporting F-P oscillations. The polariton lasing exhibited a threshold of 12  μJ/cm2. Zhang et al.169 investigated the trapping of polaritons in micron-sized CsPbBr3 flakes embedded in DBRs as a microcavity [Fig. 14(g)]. They demonstrated quantized polariton states arising from the optical confinement of flakes.

    In comparison with perovskite NCs with 3D structure, quasi-2D perovskites have a quantum well (QW) structure with the advantages of large exciton binding energy and low nonradiation loss and are more easily coupled with a resonant cavity. In 2018, Fieramosca et al. observed strong exciton–photon coupling from hybrid 2D perovskite flakes. The organic ligands efficiently affected the out-of-plane exciton–photon coupling, suggesting that the organic interlayer plays a significant role in the anisotropy of the exciton and exciton polariton.179 Then, they observed highly interacting polaritons in (PEA)2PbI4 with an excitonic interaction constant as 3  μeVμm2, which was two orders higher than that of organic excitons.180 Zhang et al.181 investigated cavity polariton modes in 2D perovskite (PEA)2PbBr4 sheets. The perovskite layer naturally could act as an F-P cavity and exhibited evident cavity polariton modes with Rabi splitting energy of 259  meV. Li et al.170 first reported room temperature optical gain from 2D perovskite (NMA)2FAn1PbnX3n+1 (NMA=C10H7CH2NH3+). In these layered perovskite nanostructures, multiple QW phases naturally form an energy cascade, enabling an ultrafast energy transfer process from higher energy bandgap QWs (n<5) to lower energy bandgap QWs (n>5). They obtained tunable ASE ranging from 530 to 810 nm with low ASE threshold (<20.0  μJ/cm2) [Fig. 14(h)]. Later, lasing based on these quasi-2D perovskite nanostructure has also been realized by researchers, e.g., Liang et al. investigated multicolor lasing from (BA)2(MA)n1PbnI3n+1 (BA=C4H9NH3+) in 2019.182 Most recently, Liu et al. shrank the quasi-2D perovskites laser to the deep-subwavelength scale with 50 nm, which was the smallest room temperature all-dielectric laser.183 They revealed the contribution from excitons and polarons to the high optical gain, which provided an insight into the design of next-generation integrated laser sources. Qin et al.171,184 found that the triplet excitons in hybrid quasi-2D perovskite have a lifetime up to 1  μs, which might cause the disappearance of the laser. Then, using a distributed-feedback (DFB) cavity with a high Q and triplet management strategies, they realized stable room-temperature CW lasing in quasi-2D perovskite films [Fig. 14(i)]. The representative works about perovskite lasers in recent years are summarized in Table 1. All of these progresses prove the potential of perovskite materials in micro/nanolasers.

    MaterialsNanostructureLaser modeEmission wavelengthThresholdYearRef.
    CsPbX3QD on silica sphereWGM400 to 700 nm5 to 22  μJ/cm22015127
    CsPbBr3CsPbX3/SiO2 compositeRandom520 to 530 nm40  μJ/cm22017131
    FAPbBr3FAPbX3/SiO2Random540 nm413.7  μJ/cm22020136
    CsPbBr3QD in silica sphereRandom/WGM530 nm430  μJ/cm22019137
    CsPbBr3QD in capillary tubeWGN530 to 540 nm11  μJ/cm22015138
    CsPbBr3QD in capillary tubeWGM535 nm0.9  mJ/cm22016139
    FAPbBr3QD in capillary tubeWGM540 to 550 nm0.31  mJ/cm22019132
    CsPbBr3DBR/CsPbBr3QD/DBRF-P460 to 650 nm9  μJ/cm22017133
    CsPbBr3DBR/CsPbBr3QD/DBRF-P520 nm0.39  μJ/cm22017134
    FAPbBr3Flexile DBR/FAPbBr3film/DBRF-P552.7 nm18.3  μJ/cm22017135
    MAPbBr3DBR/MAPbBr3film/AgF-P552 nm421  μJ/cm22020140
    MAPbX3NWsF-P500 to 790 nm0.22  μJ/cm22015144
    MAPbX3NWsF-P551, 750, 777 nm11  μJ/cm2201549
    CsPbX3NWs and NPsF-P430, 532, 550 nm5  μJ/cm2201655
    CsPbX3NWsF-P420 to 710 nm6.2  μJ/cm22016145
    CsPbX3Micro/NRsF-P428 to 628 nm14.1  μJ/cm2201775
    CsPbCl33xBr3xNWsF-P480 to 525 nm11.7 to 35.0  μJ/cm22020146
    MAPbI3NPsWGM780 nm37  μJ/cm2201480
    MAPbClxBr3xMicrodisksWGM525 to 558 nm3.6  μJ/cm22015150
    MAPbI3MicroplateletsWGM780 nm12  μJ/cm22016151
    MAPbBr3MicroplatesWGM550 nm20  μJ/cm22017152
    MAPbI3Triangular nanoplateletsWGM780 nm18.7  μJ/cm22019148
    CsPbX3NanoplateletsWGM400 to 700 nm2.0 to 10.0  μJ/cm22016149
    CsPbI3NSsWGM702 to 725 nm0.3  mJ/cm2201886
    CsPb2Br5MicroplatesF-P530, 540 nm230  μJ/cm22020153
    WGM180  μJ/cm2
    CsPbX3MSsWGM425 to 715 nm0.42  μJ/cm22017100
    CsPbBr3MSsWGM520 to 542 nm203.7  μJ/cm22018154
    CsPbBr3NanocuboidsF-P531 nm40.2  μJ/cm22018129
    MAPbBr3PyramidsF-P530 nm26  μJ/cm22018102
    CsPbI3PyramidsF-P720 nm21.56 to 53.15  μJ/cm22019103
    MAPbBr3Microwire arrayF-P554 nm5.9  μJ/cm22016156
    MAPbX3NW arrayF-P543 nm12.3  μJ/cm22017157
    MAPbX3Microplate arrayWGM510 to 780 nm3.5  μJ/cm22016158
    CsPbX3QDs arrayWGM534 nm200  μJ/cm22018159
    MAPbX3Microdisk arrayWGM510 to 650 nm21.3  μJ/cm22019160
    CsPbBr3CsPbBr3 microrod/Al nanoparticleSP540 nm7.24  μJ/cm22017172
    CsPbBrI3CsPbBr3/PEDOT:PSS/Au nanoparticleSP542 nm157.6  μJ/cm22018174
    MAPbBr3MAPbBr3/Al2O3/TiNSP550 nm10  μJ/cm22021164
    CsPbBr3Ag/CsPbBr3/Al2O3/AuSP534 nm1.9  W/cm22021165
    CsPbBr3CsPbBr3/AuSP495 to 520 nm2.0 mW2021166
    CsPbBr3NWsF-P520 nm8  μJ/cm22018167
    MAPbBr3Micro/NWsF-P550 nm15  μJ/cm22018175
    CsPbBr3NanoribbonsF-P (CW lasing)2.34 eV0.13  kW/cm22020168
    CsPbCl3DBR/CsPbCl3/DBRF-P2.9 eV12  μJ/cm22017178
    CsPbBr3DBR/CsPbBr3/DBRF-P2.3 eV0.25  μJ/cm22020169
    (BA)2(MA)n1PbnI3n+1Quasi-2D perovskite flakesF-P630, 663, 687 nm4.8  μJ/cm22019182
    PEA2An1PbnBr3n+1 (A: MA, Cs)UV glue/quasi-2D perovskite/glassF-P539 nm10.5  μJ/cm22021183
    PEA-FAPbxBryQuasi-2D perovskite on DFBCW lasing553 nm32.8  μJ/cm22020171
    NMA-FAPbxBry555 nm4.7  μJ/cm2

    Table 1. Lasing performance of perovskite.

    4 Conclusion and Outlook

    Over the last few years, tremendous investigations have been carried out on metal halide perovskite materials, especially studies of the corresponding physicochemical properties and exploration of relevant applications in optoelectronic devices. In this review, we summarized the recent developments of the synthesis strategies, the morphological control, and lasing application of metal halide perovskite materials. The various synthetic methods for the fabrication of perovskite NCs have been investigated in previous researches, including the solution method and chemical deposition method. Moreover, the morphology of perovskite NCs can be controlled with different dimensions via adjusting the reaction conditions. Their structure-related optical properties were investigated on the single-particle with various structures as 0D, 1D, 2D, and 3D, enabling their potential in LEDs, solar cells, photodetectors, and lasers.

    In spite of the tremendous advances in perovskite materials and perovskite-based lasers so far, there are still many issues to be further solved. The central issue of perovskite materials is their instability, which is the biggest obstacle for their industrialization. Although enormous work has been performed to enhance the stability of perovskites, such as the surface ligand modification or encapsulation method, the instability characteristic of the perovskites still limits their commercial applications. So far, the mechanisms of their decomposition are not yet clearly understood, hindering their further performance improvements. Another important issue related to lead halide perovskite materials is the urgent trend of reducing or removing the lead element due to its toxicity. For this purpose, some strategies have been proposed to constitute lead-free perovskites by possible substitutes using either homovalent elements such as Sn and Ge or heterovalent elements such as Bi and Sb.185,186 Unfortunately, the optoelectronic properties of lead-free perovskites have not been effectively improved. Furthermore, the nucleation and growth mechanisms of perovskite NCs are yet to be revealed clearly, which is helpful to accurately control the morphology of the perovskite NCs for better understanding structure–property relationships. Last, but not least, theoretical explanation about the photophysics of perovskite NCs is necessary to better explain the quantum size effects of perovskite crystals, which could guide the research directions to regulate and control their electronic, optical, and defect properties.

    The potential of perovskite materials in laser applications has been abundantly demonstrated. We reviewed a variety of laser cavities and summarized the dependence between the resonant cavity and the structure of perovskite NCs. Various linear and nonlinear perovskite lasers with an ultralow threshold have been realized in single perovskite NCs with different dimensions. Owing to the large gain coefficient and long-distance ambipolar carrier-transport, perovskites have great potential in electrically driven lasers, which have huge application value in integrated optoelectronic devices. But until now, all of the obtained perovskite lasers are pumped by laser excitation. The research about electrically pumped perovskite lasers has not been realized. Further investigation of resonant cavities, together with further reduction of the lasing threshold under optical excitation via optimization of the material properties, will boost the realization for electrically driven lasers of perovskites. The future trend of the perovskite-based laser is to integrate with optoelectronic components for further waveguide and signal processing. More importantly, the resonance and gain of perovskite materials and perovskite-based lasers need photophysical theory, which will inspire exploring the carrier relaxation and charge transfer processes of high-performance devices.

    References

    [1] D. Weber. CH3NH3SnBrxI3x(x=03), a Sn(II)-system with cubic perovskite structure. Zeitschrift Fur Naturforsch. Sect. B, 33, 862-865(1978). https://doi.org/10.1515/znb-1978-0809

    [2] D. Weber. CH3NH3PbX3, a Pb(II)-system with cubic perovskite structure. Zeitschr. Naturforsch. Sect. B, 33, 1443-1445(1978). https://doi.org/10.1515/znb-1978-1214

    [3] D. Weber. The Perovskite system CH3NH3[PbnSn1nX3] (X = C1, Br, I). Zeitschr. Naturforsch. Sect. B, 34, 939-941(1979). https://doi.org/10.1515/znb-1979-0712

    [4] A. Kojima et al. Organometal halide perovskites as visible-light sensitizers for photovoltaic cells. J. Am. Chem. Soc., 131, 6050-6051(2009).

    [5] S. D. Stranks, H. J. Snaith. Metal-halide perovskites for photovoltaic and light-emitting devices. Nat. Nanotechnol., 10, 391-402(2015).

    [6] R. Gottesman, A. Zaban. Perovskites for photovoltaics in the spotlight: photoinduced physical changes and their implications. Acc. Chem. Res., 49, 320-329(2016).

    [7] Q. Lin et al. Organohalide perovskites for solar energy conversion. Acc. Chem. Res., 49, 545-553(2016).

    [8] N. G. Park et al. Towards stable and commercially available perovskite solar cells. Nat. Energy, 3, 16152(2016).

    [9] J. Seo et al. Rational strategies for efficient perovskite solar cells. Acc. Chem. Res., 49, 562-572(2016).

    [10] W. Zhang et al. Metal halide perovskites for energy applications. Nat. Energy, 3, 16048(2016).

    [11] P. Zhang et al. Perovskite solar cells with ZnO electron-transporting materials. Adv. Mater., 30, 1703737(2018).

    [12] A. K. Jena et al. Halide perovskite photovoltaics: background, status, and future prospects. Chem. Rev., 119, 3036-3103(2019).

    [13] M. Jung et al. Perovskite precursor solution chemistry: from fundamentals to photovoltaic applications. Chem. Soc. Rev., 48, 2011-2038(2019).

    [14] M. Ahmadi et al. A review on organic-inorganic halide perovskite photodetectors: device engineering and fundamental physics. Adv. Mater., 29, 1605242(2017).

    [15] F. P. G. de Arquer et al. Solution-processed semiconductors for next-generation photodetectors. Nat. Rev. Mater., 2, 16100(2017).

    [16] W. Wang et al. Research progress of perovskite materials in photocatalysis- and photovoltaics-related energy conversion and environmental treatment. Chem. Soc. Rev., 44, 5371-5408(2015).

    [17] K. Xiao et al. All-perovskite tandem solar cells with 24.2% certified efficiency and area over 1cm2 using surface-anchoring zwitterionic antioxidant. Nat. Energy, 5, 870-880(2020). https://doi.org/10.1038/s41560-020-00705-5

    [18] X. H. Luo et al. Progress of all-perovskite tandem solar cells: the role of narrow-bandgap absorbers. Sci. China-Chem., 64, 218-227(2020).

    [19] R. Meitzner et al. Agrivoltaics-the perfect fit for the future of organic photovoltaics. Adv. Energy Mater., 11, 2002551(2020).

    [20] T. Moot et al. Choose your own adventure: fabrication of monolithic all-perovskite tandem photovoltaics. Adv. Mater., 32, 2003312(2020).

    [21] S. Kondo et al. Photoluminescence and stimulated emission from microcrystalline CsPbCl3 films prepared by amorphous-to-crystalline transformation. Phys. Rev. B, 70, 205322(2004). https://doi.org/10.1103/PhysRevB.70.205322

    [22] S. Kondo et al. Confinement-enhanced stimulated emission in microcrystalline CsPbCl3 films grown from the amorphous phase. J. Cryst. Growth, 282, 94-104(2005). https://doi.org/10.1016/j.jcrysgro.2005.04.088

    [23] G. C. Xing et al. Low-temperature solution-processed wavelength-tunable perovskites for lasing. Nat. Mater., 13, 476-480(2014).

    [24] S. Kondo et al. High intensity photoluminescence of microcrystalline CsPbBr3 films: evidence for enhanced stimulated emission at room temperature. Curr. Appl. Phys., 7, 1-5(2007). https://doi.org/10.1016/j.cap.2005.08.001

    [25] F. Zhang et al. Brightly luminescent and color-tunable colloidal CH3NH3PbX3 (X = Br, I, Cl) quantum dots: potential alternatives for display technology. ACS Nano, 9, 4533-4542(2015). https://doi.org/10.1021/acsnano.5b01154

    [26] V. Adinolfi et al. The in-gap electronic state spectrum of methylammonium lead iodide single-crystal perovskites. Adv. Mater., 28, 3406-3410(2016).

    [27] W. Metaferia et al. Gallium arsenide solar cells grown at rates exceeding 300 μm  h1 by hydride vapor phase epitaxy. Nat. Commun., 10, 3361(2019). https://doi.org/10.1038/s41467-019-11341-3

    [28] X. P. Shen et al. Improved air-stability of an organic-inorganic perovskite with anhydrously transferred graphene. J. Mater. Chem. C, 6, 8663-8669(2018).

    [29] Y. Sun et al. Long-term stability of organic-inorganic hybrid perovskite solar cells with high efficiency under high humidity conditions. J. Mater. Chem. A, 5, 1374-1379(2017).

    [30] H. C. Yu et al. Organic-inorganic perovskite plasmonic nanowire lasers with a low threshold and a good thermal stability. Nanoscale, 8, 19536-19540(2016).

    [31] N. Wang et al. Perovskite light-emitting diodes based on solution-processed self-organized multiple quantum wells. Nat. Photonics, 10, 699-704(2016).

    [32] S. De Wolf et al. Organometallic halide perovskites: sharp optical absorption edge and its relation to photovoltaic performance. J. Phys. Chem. Lett., 5, 1035-1039(2014).

    [33] D. Chen, X. Chen. Luminescent perovskite quantum dots: synthesis, microstructures, optical properties and applications. J. Mater. Chem. C, 7, 1413-1446(2019).

    [34] Y. Zhang et al. Photonics and optoelectronics using nano-structured hybrid perovskite media and their optical cavities. Phys. Rep., 795, 1-51(2019).

    [35] H. Dong et al. Materials chemistry and engineering in metal halide perovskite lasers. Chem. Soc. Rev., 49, 951-982(2020).

    [36] J. Xu et al. Halide perovskites for nonlinear optics. Adv. Mater., 32, 1806736(2020).

    [37] Y. Bekenstein et al. Highly luminescent colloidal nanoplates of perovskite cesium lead halide and their oriented assemblies. J. Am. Chem. Soc., 137, 16008-16011(2015).

    [38] H. Huang et al. Colloidal lead halide perovskite nanocrystals: synthesis, optical properties and applications. NPG Asia Mater., 8, e328(2016).

    [39] X. M. Li et al. CsPbX3 quantum dots for lighting and displays: room-temperature synthesis, photoluminescence superiorities, underlying origins and white light-emitting diodes. Adv. Funct. Mater., 26, 2435-2445(2016). https://doi.org/10.1002/adfm.201600109

    [40] Z. X. Liu et al. Morphology-tailored halide perovskite platelets and wires: from synthesis, properties to optoelectronic devices. Adv. Opt. Mater., 6, 1800413(2018).

    [41] G. Nedelcu et al. Fast anion-exchange in highly luminescent nanocrystals of cesium lead halide perovskites (CsPbX3, X = Cl, Br, I). Nano Lett., 15, 5635-5640(2015). https://doi.org/10.1021/acs.nanolett.5b02404

    [42] L. Protesescu et al. Nanocrystals of cesium lead halide perovskites (CsPbX3, X = Cl, Br, and I): novel optoelectronic materials showing bright emission with wide color gamut. Nano Lett., 15, 3692-3696(2015). https://doi.org/10.1021/nl5048779

    [43] Y. X. Li et al. Advances in metal halide perovskite nanocrystals: synthetic strategies, growth mechanisms, and optoelectronic applications. Mater. Today, 32, 204-221(2020).

    [44] A. Fakharuddin et al. Inorganic and layered perovskites for optoelectronic devices. Adv. Mater., 31, 1807095(2019).

    [45] C. Li et al. Formability of ABX3 (X = F, CI, Br, I) halide perovskites. Acta Crystallogr. B, B64, 702-707(2008). https://doi.org/10.1107/S0108768108032734

    [46] Q. D. Sun, W. J. Yin. Thermodynamic stability trend of cubic perovskites. J. Am. Chem. Soc., 139, 14905-14908(2017).

    [47] J. Shamsi et al. Colloidal synthesis of quantum confined single crystal CsPbBr3 nanosheets with lateral size control up to the micrometer range. J. Am. Chem. Soc., 138, 7240-7243(2016). https://doi.org/10.1021/jacs.6b03166

    [48] J. Cho et al. Ligand-mediated modulation of layer thicknesses of perovskite methylammonium lead bromide nanoplatelets. Chem. Mat., 28, 6909-6916(2016).

    [49] J. Xing et al. Vapor phase synthesis of organometal halide perovskite nanowires for tunable room-temperature nanolasers. Nano Lett., 15, 4571-4577(2015).

    [50] S. B. Sun et al. Ligand-mediated synthesis of shape-controlled cesium lead halide perovskite nanocrystals via reprecipitation process at room temperature. ACS Nano, 10, 3648-3657(2016).

    [51] D. D. Zhang et al. Solution-phase synthesis of cesium lead halide perovskite nanowires. J. Am. Chem. Soc., 137, 9230-9233(2015).

    [52] J. K. Sun et al. Polar solvent induced lattice distortion of cubic CsPbI3 nanocubes and hierarchical self-assembly into orthorhombic single-crystalline nanowires. J. Am. Chem. Soc., 140, 11705-11715(2018). https://doi.org/10.1021/jacs.8b05949

    [53] D. D. Zhang et al. Synthesis of composition tunable and highly luminescent cesium lead halide nanowires through anion-exchange reactions. J. Am. Chem. Soc., 138, 7236-7239(2016).

    [54] F. Di Stasio et al. Reversible concentration-dependent photoluminescence quenching and change of emission color in CsPbBr3 nanowires and nanoplatelets. J. Phys. Chem. Lett., 8, 2725-2729(2017). https://doi.org/10.1021/acs.jpclett.7b01305

    [55] S. W. Eaton et al. Lasing in robust cesium lead halide perovskite nanowires. Proc. Natl. Acad. Sci. U. S. A., 113, 1993-1998(2016).

    [56] M. Imran et al. Colloidal synthesis of strongly fluorescent CsPbBr3 nanowires with width tunable down to the quantum confinement regime. Chem. Mat., 28, 6450-6454(2016). https://doi.org/10.1021/acs.chemmater.6b03081

    [57] Y. Liu et al. Room temperature colloidal synthesis of CsPbBr3 nanowires with tunable length, width and composition. J. Mater. Chem. C, 6, 7797-7802(2018). https://doi.org/10.1039/C8TC02636J

    [58] D. Amgar et al. Tunable length and optical properties of CsPbX3 (X = Cl, Br, I) nanowires with a few unit cells. Nano Lett., 17, 1007-1013(2017). https://doi.org/10.1021/acs.nanolett.6b04381

    [59] Z. Yuan et al. A facile one-pot synthesis of deep blue luminescent lead bromide perovskite microdisks. Chem. Commun., 51, 16385-16388(2015).

    [60] V. K. Ravi et al. Origin of the substitution mechanism for the binding of organic ligands on the surface of CsPbBr3 perovskite nanocubes. J. Phys. Chem. Lett., 8, 4988-4994(2017). https://doi.org/10.1021/acs.jpclett.7b02192

    [61] J. A. Sichert et al. Quantum size effect in organometal halide perovskite nanoplatelets. Nano Lett., 15, 6521-6527(2015).

    [62] J. Chen et al. Vapor-phase epitaxial growth of aligned nanowire networks of cesium lead halide perovskites (CsPbX3, X = Cl, Br, I). Nano Lett., 17, 460-466(2017). https://doi.org/10.1021/acs.nanolett.6b04450

    [63] S. T. Ha et al. Synthesis of organic-inorganic lead halide perovskite nanoplatelets: towards high-performance perovskite solar cells and optoelectronic devices. Adv. Opt. Mater., 2, 838-844(2014).

    [64] Z. X. Liu et al. One-step vapor-phase synthesis and quantum-confined exciton in single-crystal platelets of hybrid halide perovskites. J. Phys. Chem. Lett., 10, 2363-2371(2019).

    [65] C. K. Lin et al. Two-step patterning of scalable all-inorganic halide perovskite arrays. ACS Nano, 14, 3500-3508(2020).

    [66] W. W. Chen et al. Tunable photoluminescence of CsPbBr3 perovskite quantum dots for light emitting diodes application. J. Solid State Chem., 255, 115-120(2017). https://doi.org/10.1016/j.jssc.2017.06.006

    [67] X. Fang et al. Wide range tuning of the size and emission color of CH3NH3PbBr3 quantum dots by surface ligands. AIP Adv., 7, 085217(2017). https://doi.org/10.1063/1.4994995

    [68] R. K. Singh et al. Structural, morphological and thermodynamic parameters investigation of tunable MAPb1xCdxBr32xI2x hybrid perovskite. J. Alloys Comp., 866, 158936(2021). https://doi.org/10.1016/j.jallcom.2021.158936

    [69] S. R. Smock et al. The surface chemistry and structure of colloidal lead halide perovskite nanocrystals. Acc. Chem. Res., 54, 707-718(2021).

    [70] Y. Xie et al. Highly efficient blue-emitting CsPbBr3 perovskite nanocrystals through neodymium doping. Adv. Sci., 7, 2001698(2020). https://doi.org/10.1002/advs.202001698

    [71] H. Deng et al. Growth, patterning and alignment of organolead iodide perovskite nanowires for optoelectronic devices. Nanoscale, 7, 4163-4170(2015).

    [72] D. D. Dong et al. Bandgap tunable Csx(CH3NH3)1xPbI3 perovskite nanowires by aqueous solution synthesis for optoelectronic devices. Nanoscale, 9, 1567-1574(2017). https://doi.org/10.1039/C6NR06636D

    [73] P. C. Zhu et al. Direct conversion of perovskite thin films into nanowires with kinetic control for flexible optoelectronic devices. Nano Lett., 16, 871-876(2016).

    [74] J. He et al. In situ synthesis and macroscale alignment of CsPbBr3 perovskite nanorods in a polymer matrix. Nanoscale, 10, 15436-15441(2018). https://doi.org/10.1039/C8NR04895A

    [75] H. Zhou et al. Vapor growth and tunable lasing of band gap engineered cesium lead halide perovskite micro/nanorods with triangular cross section. ACS Nano, 11, 1189-1195(2017).

    [76] T. Qiu et al. Recent advances in one-dimensional halide perovskites for optoelectronic applications. Nanoscale, 10, 20963-20989(2018).

    [77] E. Z. Shi et al. Two-dimensional halide perovskite nanomaterials and heterostructures. Chem. Soc. Rev., 47, 6046-6072(2018).

    [78] X. S. Tang et al. Perovskite CsPb2Br5 microplate laser with enhanced stability and tunable properties. Adv. Opt. Mater., 5, 1600788(2017). https://doi.org/10.1002/adom.201600788

    [79] Z.-J. Li et al. General strategy for the growth of CsPbX3 (X = Cl, Br, I) perovskite nanosheets from the assembly of nanorods. Chem. Mat., 30, 3854-3860(2018). https://doi.org/10.1021/acs.chemmater.8b01283

    [80] Q. Zhang et al. Room-temperature near-infrared high-Q perovskite whispering-gallery planar nanolasers. Nano Lett., 14, 5995-6001(2014).

    [81] X. Qin et al. Perovskite photodetectors based on CH3NH3PbI3 single crystals. Chem.-Asian J., 11, 2675-2679(2016). https://doi.org/10.1002/asia.201600430

    [82] A. Z. Pan et al. Insight into the ligand-mediated synthesis of colloidal CsPbBr3 perovskite nanocrystals: the role of organic acid, base, and cesium precursors. ACS Nano, 10, 7943-7954(2016). https://doi.org/10.1021/acsnano.6b03863

    [83] H. Huang et al. Spontaneous crystallization of perovskite nanocrystals in nonpolar organic solvents: a versatile approach for their shape-controlled synthesis. Angew. Chem.-Int. Ed., 58, 16558-16562(2019).

    [84] J. Liu et al. Two-dimensional CH3NH3PbI3 perovskite: synthesis and optoelectronic application. ACS Nano, 10, 3536-3542(2016). https://doi.org/10.1021/acsnano.5b07791

    [85] C. Huo et al. Field-effect transistors based on van-der-Waals-grown and dry-transferred all-inorganic perovskite ultrathin platelets. J. Phys. Chem. Lett., 8, 4785-4792(2017).

    [86] Z. Zheng et al. Space-confined synthesis of 2D all-inorganic CsPbI3 perovskite nanosheets for multiphoton-pumped lasing. Adv. Opt. Mater., 6, 1800879(2017). https://doi.org/10.1002/adom.201800879

    [87] N. F. Yu et al. Light propagation with phase discontinuities: generalized laws of reflection and refraction. Science, 334, 333-337(2011).

    [88] X. J. Ni et al. Broadband light bending with plasmonic nanoantennas. Science, 335, 427-427(2012).

    [89] B. Wang et al. Visible-frequency dielectric metasurfaces for multiwavelength achromatic and highly dispersive holograms. Nano Lett., 16, 5235-5240(2016).

    [90] Y. B. Fan et al. Resonance-enhanced three-photon luminesce via lead halide perovskite metasurfaces for optical encoding. Nat. Commun., 10, 2085(2019).

    [91] S. Sun et al. All-dielectric full-color printing with TiO2 metasurfaces. ACS Nano, 11, 4445-4452(2017). https://doi.org/10.1021/acsnano.7b00415

    [92] Y. S. Gao et al. Nonlinear holographic all-dielectric metasurfaces. Nano Lett., 18, 8054-8061(2018).

    [93] H. L. Wang et al. Nanoimprinted perovskite metasurface for enhanced photoluminescence. Opt. Express, 25, 1162-1171(2017).

    [94] B. Jeong et al. Polymer-assisted nanoimprinting for environment- and phase-stable perovskite nanopatterns. ACS Nano, 14, 1645-1655(2020).

    [95] K. Y. Wang et al. Micro- and nanostructured lead halide perovskites: from materials to integrations and devices. Adv. Mater., 33, 2000306(2021).

    [96] C. Zhang et al. Lead halide perovskite-based dynamic metasurfaces. Laser Photonics Rev., 13, 1900079(2019).

    [97] B. Gholipour et al. Organometallic perovskite metasurfaces. Adv. Mater., 29, 1604268(2017).

    [98] S. V. Makarov et al. Multifold emission enhancement in nanoimprinted hybrid perovskite metasurfaces. ACS Photonics, 4, 728-735(2017).

    [99] Z. P. Hu et al. Robust cesium lead halide perovskite microcubes for frequency upconversion lasing. Adv. Opt. Mater., 5, 1700419(2017).

    [100] B. Tang et al. Single-mode lasers based on cesium lead halide perovskite sub-micron spheres. ACS Nano, 11, 10681-10688(2017).

    [101] Z. Wei et al. Synthesis and encapsulation of all inorganic perovskite nanocrystals by microfluidics. J. Mater. Sci., 54, 6841-6852(2019).

    [102] Y. Mi et al. Fabry–Perot oscillation and room temperature lasing in perovskite cube-corner pyramid cavities. Small, 14, 1703136(2018).

    [103] L. Yang et al. Temperature-dependent lasing of CsPbI3 triangular pyramid. J. Phys. Chem. Lett., 10, 7056-7061(2019). https://doi.org/10.1021/acs.jpclett.9b02703

    [104] M. Chen et al. Controlled growth of dodecapod-branched CsPbBr3 nanocrystals and their application in white light emitting diodes. Nano Energy, 53, 559-566(2018). https://doi.org/10.1016/j.nanoen.2018.09.020

    [105] F. Li et al. Controlled fabrication, lasing behavior and excitonic recombination dynamics in single crystal CH3NH3PbBr3 perovskite cuboids. Sci. Bull., 64, 698-704(2019). https://doi.org/10.1016/j.scib.2019.04.016

    [106] J. L. Xu et al. Organized chromophoric assemblies for nonlinear optical materials: towards (sub)wavelength scale architectures. Small, 11, 1113-1129(2015).

    [107] A. Autere et al. Nonlinear optics with 2D layered materials. Adv. Mater., 30, 1705963(2018).

    [108] J. L. Xu et al. Self-assembled organic microfibers for nonlinear optics. Adv. Mater., 25, 2084-2089(2013).

    [109] J. B. Xiong et al. Wavelength dependent nonlinear optical response of tetraphenylethene aggregation-induced emission luminogens. Mat. Chem. Front., 2, 2263-2271(2018).

    [110] E. Garmire. Nonlinear optics in daily life. Opt. Express, 21, 30532-30544(2013).

    [111] B. B. Gu et al. Molecular nonlinear optics: recent advances and applications. Adv. Opt. Photonics, 8, 328-369(2016).

    [112] O. Tokel et al. In-chip microstructures and photonic devices fabricated by nonlinear laser lithography deep inside silicon. Nat. Photonics, 11, 639(2017).

    [113] S. H. Yue et al. Multimodal nonlinear optical microscopy. Laser Photonics Rev., 5, 496-512(2011).

    [114] M. Savoini et al. THz generation and detection by fluorenone based organic crystals. ACS Photonics, 5, 671-677(2018).

    [115] H. Linnenbank et al. Temperature dependent two-photon photoluminescence of CH3NH3PbBr3: structural phase and exciton to free carrier transition. Opt. Mater. Express, 8, 511-521(2018). https://doi.org/10.1364/OME.8.000511

    [116] Y. Wang et al. Nonlinear absorption and low-threshold multiphoton pumped stimulated emission from all-inorganic perovskite nanocrystals. Nano Lett., 16, 448-453(2016).

    [117] G. Walters et al. Two-photon absorption in organometallic bromide perovskites. ACS Nano, 9, 9340-9346(2015).

    [118] B. S. Kalanoor et al. Third-order optical nonlinearities in organometallic methylammonium lead iodide perovskite thin films. ACS Photonics, 3, 361-370(2016).

    [119] R. A. Ganeev et al. Strong nonlinear absorption in perovskite films. Opt. Mater. Express, 8, 1472-1483(2018).

    [120] J. Zhang et al. Thickness-dependent nonlinear optical properties of CsPbBr3 perovskite nanosheets. Opt. Lett., 42, 3371-3374(2017). https://doi.org/10.1364/OL.42.003371

    [121] K. N. Krishnakanth et al. Broadband femtosecond nonlinear optical properties of CsPbBr3 perovskite nanocrystals. Opt. Lett., 43, 603-606(2018). https://doi.org/10.1364/OL.43.000603

    [122] Q. Wei et al. Recent progress in metal halide perovskite micro- and nanolasers. Adv. Opt. Mater., 7, 1900080(2019).

    [123] F. Hide et al. Semiconducting polymers: a new class of solid-state laser materials. Science, 273, 1833-1836(1996).

    [124] B. R. Sutherland et al. Perovskite thin films via atomic layer deposition. Adv. Mater., 27, 53-58(2015).

    [125] Q. Liao et al. Tunable halide perovskites for miniaturized solid-state laser applications. Adv. Opt. Mater., 7, 1900099(2019).

    [126] Q. Zhang et al. Advances in small perovskite-based lasers. Small Methods, 3, 1700163(2017).

    [127] S. Yakunin et al. Low-threshold amplified spontaneous emission and lasing from colloidal nanocrystals of caesium lead halide perovskites. Nat. Commun., 6, 8056(2015).

    [128] B. R. Sutherland et al. Conformal organohalide perovskites enable lasing on spherical resonators. ACS Nano, 8, 10947-10952(2014).

    [129] Z. Liu et al. Robust subwavelength single-mode perovskite nanocuboid laser. ACS Nano, 12, 5923-5931(2018).

    [130] C. Zhao et al. Stable two-photon pumped amplified spontaneous emission from millimeter-sized CsPbBr3 single crystals. J. Phys. Chem. Lett., 10, 2357-2362(2019). https://doi.org/10.1021/acs.jpclett.9b00734

    [131] X. M. Li et al. Amino-mediated anchoring perovskite quantum dots for stable and low-threshold random lasing. Adv. Mater., 29, 1701185(2017).

    [132] Z. Z. Liu et al. Two-photon pumped amplified spontaneous emission and lasing from formamidinium lead bromine nanocrystals. ACS Photonics, 6, 3150-3158(2019).

    [133] Y. Wang et al. Solution-processed low threshold vertical cavity surface emitting lasers from all-inorganic perovskite nanocrystals. Adv. Funct. Mater., 27, 1605088(2017).

    [134] C. Y. Huang et al. CsPbBr3 perovskite quantum dot vertical cavity lasers with low threshold and high stability. ACS Photonics, 4, 2281-2289(2017). https://doi.org/10.1021/acsphotonics.7b00520

    [135] S. Chen, A. Nurmikko. Stable green perovskite vertical-cavity surface-emitting lasers on rigid and flexible substrates. ACS Photonics, 4, 2486-2494(2017).

    [136] J. Yang et al. High efficiency up-conversion random lasing from formamidinium lead bromide/amino-mediated silica spheres composites. Adv. Opt. Mater., 8, 2000290(2020).

    [137] Z. Liu et al. Stable and enhanced frequency up-converted lasing from CsPbBr3 quantum dots embedded in silica sphere. Opt. Express, 27, 9459-9466(2019). https://doi.org/10.1364/OE.27.009459

    [138] Y. Wang et al. All-inorganic colloidal perovskite quantum dots: a new class of lasing materials with favorable characteristics. Adv. Mater., 27, 7101-7108(2015).

    [139] Y. Q. Xu et al. Two-photon-pumped perovskite semiconductor nanocrystal lasers. J. Am. Chem. Soc., 138, 3761-3768(2016).

    [140] X. Li et al. Two-photon-pumped high-quality, single-mode vertical cavity lasing based on perovskite monocrystalline films. Nano Energy, 68, 104334(2020).

    [141] Z. Liu et al. Advances in inorganic and hybrid perovskites for miniaturized lasers. Nanophotonics, 9, 2251-2272(2020).

    [142] A. S. Polushkin et al. Single-particle perovskite lasers: from material properties to cavity design. Nanophotonics, 9, 599-610(2020).

    [143] Z. Liu et al. Research progress of low-dimensional metal halide perovskites for lasing applications. Chin. Phys. B, 27, 114209(2018).

    [144] H. M. Zhu et al. Lead halide perovskite nanowire lasers with low lasing thresholds and high quality factors. Nat. Mater., 14, 636-642(2015).

    [145] Y. P. Fu et al. Broad wavelength tunable robust lasing from single-crystal nanowires of cesium lead halide perovskites (CsPbX3, X = Cl, Br, I). ACS Nano, 10, 7963-7972(2016). https://doi.org/10.1021/acsnano.6b03916

    [146] B. Tang et al. Energy transfer and wavelength tunable lasing of single perovskite alloy nanowire. Nano Energy, 71, 104641(2020).

    [147] X. Wang et al. Cesium lead halide perovskite triangular nanorods as high-gain medium and effective cavities for multiphoton-pumped lasing. Nano Res., 10, 3385-3395(2017).

    [148] G. Li et al. Record-low-threshold lasers based on atomically smooth triangular nanoplatelet perovskite. Adv. Funct. Mater., 29, 1805553(2019).

    [149] Q. Zhang et al. High-quality whispering-gallery-mode lasing from cesium lead halide perovskite nanoplatelets. Adv. Funct. Mater., 26, 6238-6245(2016).

    [150] Q. Liao et al. Perovskite microdisk microlasers self-assembled from solution. Adv. Mater., 27, 3405-3410(2015).

    [151] X. F. Liu et al. Periodic organic-inorganic halide perovskite microplatelet arrays on silicon substrates for room-temperature lasing. Adv. Sci., 3, 1600137(2016).

    [152] Q. Wei et al. Two-photon optical properties in individual organic-inorganic perovskite microplates. Adv. Opt. Mater., 5, 1700809(2017).

    [153] Z. Z. Liu et al. Mode selection and high-quality upconversion lasing from perovskite CsPb2Br5 microplates. Photon. Res., 8, A31-A38(2020). https://doi.org/10.1364/PRJ.399960

    [154] B. Tang et al. Ultrahigh quality upconverted single-mode lasing in cesium lead bromide spherical microcavity. Adv. Opt. Mater., 6, 1800391(2018).

    [155] B. Zhou et al. Linearly polarized lasing based on coupled perovskite microspheres. Nanoscale, 12, 5805-5811(2020).

    [156] K. Y. Wang et al. High-density and uniform lead halide perovskite nanolaser array on silicon. J. Phys. Chem. Lett., 7, 2549-2555(2016).

    [157] P. Liu et al. Organic–inorganic hybrid perovskite nanowire laser arrays. ACS Nano, 11, 5766-5773(2017).

    [158] J. Feng et al. ‘Liquid knife’ to fabricate patterning single-crystalline perovskite microplates toward high-performance laser arrays. Adv. Mater., 28, 3732-3741(2016).

    [159] C. H. Lin et al. Large-area lasing and multicolor perovskite quantum dot patterns. Adv. Opt. Mater., 6, 1800474(2018).

    [160] K. Wang et al. Wettability-guided screen printing of perovskite microlaser arrays for current-driven displays. Adv. Mater., 32, 2001999(2020).

    [161] C. Huang et al. Ultrafast control of vortex microlasers. Science, 367, 1018-1021(2020).

    [162] C. Li et al. Surface-plasmon-assisted metal halide perovskite small lasers. Adv. Opt. Mater., 7, 1900279(2019).

    [163] T. S. Kao et al. Localized surface plasmon for enhanced lasing performance in solution-processed perovskites. Opt. Express, 24, 20696-20702(2016).

    [164] Y.-J. Lu et al. Upconversion plasmonic lasing from an organolead trihalide perovskite nanocrystal with low threshold. ACS Photonics, 8, 335-342(2020).

    [165] Y. H. Hsieh et al. Perovskite quantum dot lasing in a gap-plasmon nanocavity with ultralow threshold. ACS Nano, 14, 11670-11676(2020).

    [166] S. Li et al. Optically-controlled quantum size effect in a hybrid nanocavity composed of a perovskite nanoparticle and a thin gold film. Laser Photonics Rev., 15, 2000480(2021).

    [167] W. Du et al. Strong exciton–photon coupling and lasing behavior in all-inorganic CsPbBr3 micro/nanowire Fabry-Pérot cavity. ACS Photonics, 5, 2051-2059(2018). https://doi.org/10.1021/acsphotonics.7b01593

    [168] Q. Shang et al. Role of the exciton-polariton in a continuous-wave optically pumped CsPbBr3 perovskite laser. Nano Lett., 20, 6636-6643(2020). https://doi.org/10.1021/acs.nanolett.0c02462

    [169] S. Zhang et al. Trapped exciton–polariton condensate by spatial confinement in a perovskite microcavity. ACS Photonics, 7, 327-337(2020).

    [170] M. Li et al. Amplified spontaneous emission based on 2D Ruddlesden-Popper perovskites. Adv. Funct. Mater., 28, 1707006(2018).

    [171] C. Qin et al. Stable room-temperature continuous-wave lasing in quasi-2D perovskite films. Nature, 585, 53-57(2020).

    [172] S. Wang et al. Maskless fabrication of aluminum nanoparticles for plasmonic enhancement of lead halide perovskite lasers. Adv. Opt. Mater., 5, 1700529(2017).

    [173] X. Wu et al. Highly stable enhanced near-infrared amplified spontaneous emission in solution-processed perovskite films by employing polymer and gold nanorods. Nanoscale, 11, 1959-1967(2019).

    [174] J. Yang et al. Enhanced single-mode lasers of all-inorganic perovskite nanocube by localized surface plasmonic effect from Au nanoparticles. J. Luminesc., 208, 402-407(2019).

    [175] S. Zhang et al. Strong exciton-photon coupling in hybrid inorganic-organic perovskite micro/nanowires. Adv. Opt. Mater., 6, 1701032(2018).

    [176] Q. Shang et al. Enhanced optical absorption and slowed light of reduced-dimensional CsPbBr3 nanowire crystal by exciton-polariton. Nano Lett., 20, 1023-1032(2020). https://doi.org/10.1021/acs.nanolett.9b04175

    [177] Q. Shang et al. Surface plasmon enhanced strong exciton-photon coupling in hybrid inorganic-organic perovskite nanowires. Nano Lett., 18, 3335-3343(2018).

    [178] R. Su et al. Room-temperature polariton lasing in all-inorganic perovskite nanoplatelets. Nano Lett., 17, 3982-3988(2017).

    [179] A. Fieramosca et al. Tunable out-of-plane excitons in 2D single-crystal perovskites. ACS Photonics, 5, 4179-4185(2018).

    [180] A. Fieramosca et al. Two-dimensional hybrid perovskites sustaining strong polariton interactions at room temperature. Sci. Adv., 5, eaav9967(2019).

    [181] X. Zhang et al. Exciton-polariton properties in planar microcavity of millimeter-sized two-dimensional perovskite sheet. ACS Appl. Mater. Interfaces, 12, 5081-5089(2020).

    [182] Y. Liang et al. Lasing from mechanically exfoliated 2D homologous Ruddlesden–Popper perovskite engineered by inorganic layer thickness. Adv. Mater., 31, 1903030(2019).

    [183] Z. Liu et al. Subwavelength-polarized quasi-two-dimensional perovskite single-mode nanolaser. ACS Nano, 15, 6900-6908(2021).

    [184] C. Qin et al. Triplet management for efficient perovskite light-emitting diodes. Nat. Photonics, 14, 70-75(2020).

    [185] G. C. Xing et al. Solution-processed tin-based perovskite for near-infrared lasing. Adv. Mater., 28, 8191-8196(2016).

    [186] Z. Y. Wu et al. Room-temperature near-infrared random lasing with tin-based perovskites prepared by CVD processing. J. Phys. Chem. C, 125, 5180-5184(2021).

    Zhiping Hu, Zhengzheng Liu, Zijun Zhan, Tongchao Shi, Juan Du, Xiaosheng Tang, Yuxin Leng. Advances in metal halide perovskite lasers: synthetic strategies, morphology control, and lasing emission[J]. Advanced Photonics, 2021, 3(3): 034002
    Download Citation