Minghuan Cui, Chaochao Qin, Yuanzhi Jiang, Shichen Zhang, Changjiu Sun, Mingjian Yuan, Yonggang Yang, Yufang Liu, "Tuning exciton dynamics by the dielectric confinement effect in quasi-two-dimensional perovskites," Photonics Res. 12, 563 (2024)

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- Photonics Research
- Vol. 12, Issue 3, 563 (2024)

Fig. 1. (a) Schematic illustration of the dielectric confinement effect in a quantum well structure. Note that ε w is much larger than ε b . (b) Schematic molecular structures of ethanolamine (EA + ), p -fluorophenethylammonium (p - FPEA + ), and phenethylammonium (PEA + ). (c) Schematic crystal structure of EA 2 PbBr 4 , p - FPEA 2 PbBr 4 , and PEA 2 PbBr 4 . (d) UV-vis absorption (dashed line) and steady-state PL (solid line) spectra of EA 2 PbBr 4 , p - FPEA 2 PbBr 4 , and PEA 2 PbBr 4 perovskite films. (e) XRD patterns of EA 2 PbBr 4 , p - FPEA 2 PbBr 4 , and PEA 2 PbBr 4 perovskite films.

Fig. 2. TA spectra (vis-pseudocolor representation) and TA dynamics (black dots and lines) of a representative probe wavelength for (a) EA 2 PbBr 4 , (b) p - FPEA 2 PbBr 4 , and (c) PEA 2 PbBr 4 perovskite films. Note: The orange coordinate scale corresponds to the TA dynamics of a representative probe wavelength, and the black coordinate scale corresponds to the TA spectra. (d) PLQYs as a function of maximum phonon modulation amplitude. Inset: Coherent phonon dynamics (the residuals after subtracting the contribution of exciton population from origin kinetics) of three perovskite films. (e) Population dynamics of EA 2 PbBr 4 , p - FPEA 2 PbBr 4 , and PEA 2 PbBr 4 perovskite films. (f) Coherent phonon circumvents the defect capture process in perovskite thin films.

Fig. 3. (a) UV-vis absorption (dashed line) and steady-state PL (solid line) spectra of EA 2 MA 3 Pb 4 Br 13 , p - FPEA 2 MA 3 Pb 4 Br 13 , and PEA 2 MA 3 Pb 4 Br 13 perovskite films. (b) XRD patterns of EA 2 MA 3 Pb 4 Br 13 , p - FPEA 2 MA 3 Pb 4 Br 13 , and PEA 2 MA 3 Pb 4 Br 13 perovskite films. Temperature-dependent integrating PL intensity at different temperatures and corresponding fitting curves for (c) EA 2 MA 3 Pb 4 Br 13 , (d) p - FPEA 2 MA 3 Pb 4 Br 13 , and (e) PEA 2 MA 3 Pb 4 Br 13 perovskite films. TA spectra (vis-pseudocolor representation) and TA dynamics (black dots and lines) of a representative probe wavelength for (f) EA 2 MA 3 Pb 4 Br 13 , (g) p - FPEA 2 MA 3 Pb 4 Br 13 , and (h) PEA 2 MA 3 Pb 4 Br 13 perovskite films. Note: The orange ordinate scale corresponds to TA dynamics of a representative probe wavelength, and the black ordinate scale corresponds to TA spectra.

Fig. 4. (a)–(c) TA spectra at representative delay times of EA 2 MA 3 Pb 4 Br 13 , p - FPEA 2 MA 3 Pb 4 Br 13 , and PEA 2 MA 3 Pb 4 Br 13 perovskite films, respectively. Inset: Transfer processes in population dynamics of three perovskite films. (d) PLQYs as a function of maximum phonon modulation amplitude. Inset: Coherent phonon dynamics of the three perovskite films. (e) Biexciton Auger recombination kinetics. The circles, squares, and triangles represent the two-by-two subtraction (P 2 –P 1 , P 3 –P 2 , and P 3 –P 1 ) from the TA population dynamics at three different pump fluences (P 1 , P 2 , and P 3 ). The biexciton Auger recombination lifetime (τ ) is obtained by averaging the three time constants from the fittings using a single exponential function.
Table 1. Fitting Parameters of the GSB Kinetics of ⟨ n ⟩ = 1 Quasi-2D RPP Films
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Table 2. Variation (Δ A , the last value—the initial value) of TA Population Dynamics and Transfer Ratio for EA2MA3Pb4Br13, p -FPEA2MA3Pb4Br13, and PEA2MA3Pb4Br13 Perovskite Films

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