Multiexciton Dynamics and Lattice Responses Associated with Amplified Spontaneous Emission in Metal Halide Perovskites

IF 4.5 2区化学 Q2 CHEMISTRY, PHYSICAL

The Journal of Physical Chemistry Letters Pub Date : 2026-10-21 DOI:10.1021/acs.jpclett.6c02776

Hyeonji Lee,EunSeo Jang,Kwangdong Roh,JunWoo Kim

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Abstract

Amplified spontaneous emission (ASE) in metal halide perovskites occurs under intense photoexcitation, where multiexciton (ME) states contribute to population inversion. Here, we investigate how A-site compositional modification regulates ASE in FAPbBr3 films partially substituted with methylammonium (MA). The ASE threshold varies nonmonotonically with MACl additive concentration despite nearly linear bandgap shifts. Fluence-dependent transient absorption signals were decomposed into odd-order nonlinear responses, confirming that the picosecond component emerging at high fluence originates from ME states. The ME lifetime exhibits a pronounced MACl concentration dependence that closely follows the ASE threshold. Coherent phonon analysis reveals reduced phonon frequencies at intermediate MA concentrations, consistent with slower lattice modulation and prolonged ME lifetimes. MA substitution also modifies film morphology and reduces void-like features associated with optical scattering. These results show that ASE performance is jointly governed by ME relaxation dynamics and photon propagation losses.

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金属卤化物钙钛矿中与放大自发辐射相关的多激子动力学和晶格响应

金属卤化物钙钛矿的放大自发发射（ASE）发生在强光激发下，其中多激子（ME）态有助于种群反转。在这里，我们研究了a位组成修饰如何调节部分被甲基铵（MA）取代的FAPbBr3薄膜中的ASE。尽管带隙位移接近线性，但ASE阈值随MACl加性浓度呈非单调变化。将依赖于通量的瞬态吸收信号分解为奇阶非线性响应，证实了在高通量下出现的皮秒分量来源于ME态。ME寿命表现出明显的MACl浓度依赖性，与ASE阈值密切相关。相干声子分析显示，在中等MA浓度下声子频率降低，与较慢的晶格调制和延长的ME寿命一致。MA取代也改变了薄膜形态，减少了与光学散射相关的空洞样特征。这些结果表明，ASE的性能是由ME弛豫动力学和光子传播损失共同决定的。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

The Journal of Physical Chemistry Letters CHEMISTRY, PHYSICAL-NANOSCIENCE & NANOTECHNOLOGY

CiteScore

9.60

自引率

7.00%

发文量

1519

审稿时长

1.6 months

期刊介绍： The Journal of Physical Chemistry (JPC) Letters is devoted to reporting new and original experimental and theoretical basic research of interest to physical chemists, biophysical chemists, chemical physicists, physicists, material scientists, and engineers. An important criterion for acceptance is that the paper reports a significant scientific advance and/or physical insight such that rapid publication is essential. Two issues of JPC Letters are published each month.