Abstract Lead halide perovskites have attracted tremendous attention recently due to their great success in the fields of photovoltaic technologies and light-emitting devices. In this work, the excitonic photoluminescence (PL) properties of all-inorganic perovskite CsPbBr3 were investigated in detail via temperature-dependent PL and Raman spectroscopy in the range of 87 K–297 K, benefiting from our recent work on solution growth of high-quality CsPbBr3 single crystals. The exciton binding energy was extracted as 37 ± 2.7 meV from temperature-dependent PL emission intensity. Furthermore, the PL emission peak energy showed complicated behaviors compared to common semiconductors. With the increase of temperature, the PL emission spectrum blueshifted below 223 K, while it was redshifted in the range of 223 K–293 K. Theoretical research indicated that the thermal expansion governs the energy bandgap evolution of CsPbBr3 below 223 K, while for higher temperatures, the contribution of electron-phonon interaction became dominant. Meanwhile, the broadening of the PL emission spectrum was mainly attributed to the exciton-longitudinal optical phonon scattering. Our results may contribute to a better understanding of the luminescence behaviors in all-inorganic perovskite CsPbBr3-based light-emitting devices in the future.

中文翻译：

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溶液生长单晶CsPbBr3钙钛矿中的激子复合机制

摘要 卤化铅钙钛矿由于在光伏技术和发光器件领域取得了巨大成功，近年来引起了极大的关注。在这项工作中，受益于我们最近在高浓度溶液生长方面的工作，通过温度相关的 PL 和拉曼光谱在 87 K-297 K 范围内详细研究了全无机钙钛矿 CsPbBr3 的激子光致发光 (PL) 特性。优质 CsPbBr3 单晶。激子结合能从温度相关的 PL 发射强度中提取为 37 ± 2.7 meV。此外，与普通半导体相比，PL 发射峰值能量表现出复杂的行为。随着温度的升高，PL发射光谱在223 K以下蓝移，而在223 K-293 K范围内发生红移。理论研究表明，热膨胀控制着 CsPbBr3 在 223 K 以下的能带隙演化，而在更高的温度下，电子-声子相互作用的贡献变得主导。同时，PL发射光谱的展宽主要归因于激子纵向光学声子散射。我们的结果可能有助于更好地理解未来全无机钙钛矿 CsPbBr3 基发光器件的发光行为。