Morana Marta, Kaiser Waldemar, Chiara Rossella, Albini Benedetta, Meggiolaro Daniele, Mosconi Edoardo, Galinetto Pietro, De Angelis Filippo, Malavasi Lorenzo
Department of Chemistry and INSTM, University of Pavia, Via Taramelli 16, Pavia 27100, Italy.
Computational Laboratory for Hybrid/Organic Photovoltaics (CLHYO), Istituto CNR di Scienze e Tecnologie Chimiche "Giulio Natta" (CNR-SCITEC), Perugia 06123, Italy.
J Phys Chem Lett. 2023 Sep 7;14(35):7860-7868. doi: 10.1021/acs.jpclett.3c01872. Epub 2023 Aug 28.
The development of broadband emitters based on metal halide perovskites (MHPs) requires the elucidation of structure-emission property correlations. Herein, we report a combined experimental and theoretical study on a series of novel low-dimensional lead chloride perovskites, including ditopic aromatic cations. Synthesized lead chloride perovskites and their bromide analogues show both narrow and broad photoluminescence emission properties as a function of their cation and halide nature. Structural analysis shows a correlation between the rigidity of the ditopic cations and the lead halide octahedral distortions. Density functional theory calculations reveal, in turn, the pivotal role of octahedral distortions in the formation of self-trapped excitons, which are responsible for the insurgence of broad emission and large Stokes shifts together with a contribution of halide vacancies. For the considered MHP series, the use of conventional octahedral distortion parameters allows us to nicely describe the trend of emission properties, thus providing a solid guide for further materials design.
基于金属卤化物钙钛矿（MHP）的宽带发射体的开发需要阐明结构与发射性质之间的相关性。在此，我们报告了对一系列新型低维氯化铅钙钛矿（包括双位芳族阳离子）的实验和理论相结合的研究。合成的氯化铅钙钛矿及其溴化物类似物根据其阳离子和卤化物性质显示出窄和宽的光致发光发射特性。结构分析表明双位阳离子的刚性与卤化铅八面体畸变之间存在相关性。反过来，密度泛函理论计算揭示了八面体畸变在自陷激子形成中的关键作用，自陷激子导致宽发射和大斯托克斯位移的出现以及卤化物空位的贡献。对于所考虑的MHP系列，使用传统的八面体畸变参数可以很好地描述发射性质的趋势，从而为进一步的材料设计提供坚实的指导。
