Self‐Trapped Exciton States in Metal Halide Perovskites van der Waals Heterostructures. Issue 12 (1st September 2022)

• Record Type: Journal Article
• Authors: Ma, Xu-Fei; Deng, Jia-Pei; Yang, Hong-Tao; Cui, Yu; Liu, Xiao-Yi; Liu, Yi-Yan; Ma, Xin-Jun; Li, Zhi-Qing; Wang, Zi-Wu
• Is Part Of: Physica status solidi. Volume 16:Issue 12(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-09-01
• Subjects: exciton binding energy -- metal halide perovskites -- self-trapped exciton -- van der Waals heterostructures; Solid state physics -- Periodicals; 530.4105
• DOI: 10.1002/pssr.202200261
• Languages: English
• ISSNs: 1862-6254

Abstract

Abstract : Self‐trapped excitons (STEs), proved to be the major source of white‐light emission in 2D metal halide perovskites (MHPs) van der Waals (vdW) heterostructures, have aroused intense interest in photovoltaic and photoelectric applications. Nevertheless, the intrinsic mechanisms of STEs in these vdW heterostructures are still ambiguous. Herein, the binding energy correction Δ E B of a STE stemming from the exciton–phonon coupling in MHPs vdW heterostructures based on the Pollmann–Büttner model is studied. It is found that there are two types of STEs with Δ E B > 0 and Δ E B < 0 . The corresponding nuclear coordinate diagrams are given to explain the differences between them and why the STEs with Δ E B < 0 are hard to be observed in experiments. The phase transition between two types of STEs can be achieved by regulating the structural parameters, such as the vertical distance between the encapsulation layers, the position of the monolayer MHP in the heterostructure as well as replacing the encapsulation materials. The theoretical results provide important insights into the analysis and modulation of STEs in 2D vdW heterostructures. Abstract : Self‐trapped excitons (STEs) are studied in 2D metal halide perovskite (MHP) van der Waals (vdW) heterojunctions based on the improved Pollmann–Büttner model, in which these exciton states are classified into the normal and abnormal STEs according to the magnitude of the correction of exciton binding energy.