Electronic structure and stability of the CH₃NH₃PbBr₃ (001) surface

Authors

Xin Huang, University of Nebraska - Lincoln
Tula R. Paudel, University of Nebraska-LincolnFollow
Peter A. Dowben, University of Nebraska-LincolnFollow
Shuai Dong, Southeast UniversityFollow
Evgeny Y. Tsymbal, University of Nebraska at LincolnFollow

Date of this Version

2016

Citation

PHYSICAL REVIEW B 94, 195309 (2016)

Comments

©2016 American Physical Society

Abstract

The energetics and the electronic structure of methylammonium lead bromine (CH₃NH₃PbBr₃) perovskite (001) surfaces are studied based on density functional theory. By examining the surface grand potential, we predict that the CH₃NH₃Br-terminated (001) surface is energetically more favorable than the PbBr₂-terminated (001) surface, under thermodynamic equilibrium conditions of bulk CH₃NH₃PbBr₃. The electronic structure of each of these two different surface terminations retains some of the characteristics of the bulk, while new surface states are found near band edges which may affect the photovoltaic performance in the solar cells based on CH₃NH₃PbBr₃. The calculated electron affinity of CH₃NH₃PbBr₃ reveals a sizable difference for the two surface terminations, indicating a possibility of tuning the band offset between the halide perovskite and adjacent electrode with proper interface engineering.