Hu Jingyun, Zhang Yiwei, Zhang Xinping
Institute of Information Photonics Technology, Beijing University of Technology, Beijing 100124, P. R. China.
J Phys Chem Lett. 2022 Jul 7;13(26):6093-6100. doi: 10.1021/acs.jpclett.2c01625. Epub 2022 Jun 27.
Exciton dynamics significantly influences the performance of the optoelectronic devices, which is intensively studied in the light-emitting perovskite of CHNHPbBr (MAPbBr). However, most of the existing investigations have focused on the free excitons. In this study, we investigate the emissive recombination from defect states in MAPbBr using temperature- and excitation-dependent photoluminescence measurements. It is revealed that two emission peaks centered at about 550 and 590 nm are presented at temperatures as low as 10 K, instead of one peak at 535 nm for the observation at room temperature. These two peaks are attributed to the emission of bound excitons after self-absorption and bulk defects, respectively. It is found that the distribution of the bound and trapped excitons is strongly influenced by the morphology of the MAPbBr films. These results provide deep insights into the exciton dynamics in MAPbBr, facilitating new physics for the design of related optoelectronic materials and devices.
激子动力学对光电器件的性能有显著影响，这在CHNHPbBr（MAPbBr）发光钙钛矿中得到了深入研究。然而，现有的大多数研究都集中在自由激子上。在本研究中，我们使用温度和激发依赖的光致发光测量方法研究了MAPbBr中缺陷态的发光复合。结果表明，在低至10 K的温度下出现了两个分别位于约550和590 nm处的发射峰，而在室温下观察到的是一个位于535 nm处的峰。这两个峰分别归因于自吸收和体缺陷后束缚激子的发射。研究发现，束缚激子和俘获激子的分布受到MAPbBr薄膜形态的强烈影响。这些结果为MAPbBr中的激子动力学提供了深入见解，有助于为相关光电子材料和器件的设计提供新的物理依据。
