Fig. 1. (Color online) (a) Schematic diagram of the QSE. (b) Photoluminescence (PL) spectras of QDs with various sizes^[32]. Copyright 2023, Wiley-VCH. (c) QDs solutions of different colors^[33]. Copyright 2023, American Chemical Society. (d) Reported spectral ranges of emission for different semiconductor nanocrystals (NCs).

Fig. 2. (Color online) (a) Schematic illustration of the synthetic apparatus for hot-injection mode^[82]. Copyright 2018, Elsevier B. V. (b) Depiction of the monodisperse NCs formation process. Stage Ⅰ: precursor reaction; Stage Ⅱ: nucleation; Stage Ⅲ: growth^[83]. Copyright 2023, Nature Publishing Group. (c) STEM images showing the progression of ZnSe(Te)/ZnSe C/S (5, 10 mL) and ZnSe(Te)/ZnSe/ZnS core/shell/shell (C/S/S) structures (scale bar: 20 nm) (inset: high-resolution STEM images, scale bar: 5 mm, with corresponding PLQY for each set of QDs)^[79]. Copyright 2024, Wiley-VCH. (d) TEM images of ZnSe/ZnS QDs after further Se precursor addition, expanding ZnSe cores to achieve the desired emission wavelength^[75]. Copyright 2013, Elsevier B. V. (e) Schematic diagram of the synthesis process of InP/GaP C/S QDs and the synthesis of InGaP alloy QDs^[77]. Copyright 2024, American Chemical Society.

Fig. 3. (Color online) (a) Progression of absorption (cyan) and emission (orange) spectra during a typical synthesis of B-QDs, with corresponding PL quantum yields indicated^[84]; Copyright 2021, American Chemical Society. (b) Diagram of the ligand exchange process using liquid-phase ZnCl₂ (ZnCl₂(l)) followed by further exchange via film-washing (ZnCl₂(f))^[49]. Copyright 2020, Nature Publishing Group. (c) Illustrations of the synthesis process for ZnSe(Te) (core), ZnSe(Te)/ZnSe C/S, and ZnSe(Te)/ZnSe/ZnS C/S/S QDs, along with associated TEM images. The atomic ratios determined via ICP-AES are as follows: core (Zn : Te : Se = 0.571 : 0.027 : 0.4), C/S (Zn : Te : Se = 0.521 : 0.002 : 0.476), C/S/S (Zn : Te : Se : S = 0.528 : 0.001 : 0.255 : 0.215)^[49]. Copyright 2020, Nature Publishing Group. (d) Representation of heterostructures showing details of shell thickness^[91]. Copyright 2019, American Chemical Society. (e) Normalized PL spectra of ZnSe(Te)/ZnSe/ZnS C/S/S QDs with varying ZnSe inner shell thicknesses (thin, medium, thick)^[92]. Copyright 2022, Elsevier B. V. (f) Energy band structure for a blue ZnSe(Te)/ZnSe/ZnSeS/ZnS multilayer QLEDs^[95]. Copyright 2020, American Chemical Society.

Fig. 4. (Color online) (a) Scheme of the synthesis process for InP/ZnS/ZnS QDs^[129]. Copyright 2022, Elsevier B. V. (b) UV−Vis absorption and PL emission spectra of InP/ZnS QDs at varying P/In ratios, along with UV−Vis absorption, PL emission spectra, and time-resolved fluorescence spectroscopy (TRPL) decays for QDs with different P/In and I/In ratios^[126]. Copyright 2017, Royal Society of Chemistry. (c) Energy level diagrams for bulk InP, GaP, and ZnS, as well as their corresponding lattice mismatches^[127]. Copyright 2020, American Chemical Society. (d) EQE−J characteristics of QLEDs incorporating InP/ZnS/ZnS-DDT QDs versus InP/ZnS/ZnS-OT QDs^[129]. Copyright 2022, Elsevier B. V. (e) Schematic illustration of the cation-exchange process from In³⁺ to Ga³⁺ for InGaP core formation, followed by ZnSeS/ZnS double-shell growth^[130]. Copyright 2020, American Chemical Society.

Fig. 5. (Color online) (a) Schematic representation of the edge amination approach^[50]. Copyright 2019, Nature Publishing Group. (b) PL spectra of HCP-DB-CDs with the color scale presented in arbitrary units^[50]. Copyright 2019, Nature Publishing Group. (c) EQE−J curves for varying concentration HCP-DB-CDs LEDs^[50]. Copyright 2019, Nature Publishing Group. (d) PL spectra of PVK, CDs, and PVK films blended with CDs at varying concentrations^[135]. Copyright 2023, Wiley-VCH. (e) PL spectra of GaN CQDs excited at 280 nm^[136]. Copyright 2019, American Chemical Society. (f) J−V characteristics of GaN: Zn QLEDs (inset: image of GaN: Zn QLEDs)^[51]. Copyright 2023, Wiley-VCH. (g) EQE−J curve for QLEDs incorporating GaN: Zn QDs^[51]. Copyright 2023, Wiley-VCH.