Theory of Layer Edge States in 2D Halide-Perovskites

Halide perovskites are one of the most promising candidate materials for photovoltaic and optoelectronic applications. Compared to the 3D organic-inorganic hybrid perovskites, the 2D layered perovskites exhibit greater tunability of band gaps and exciton binding energies, while solving the well-known stability issue of hybrid perovskites at the same time.
Recent experimental observations suggest that extrinsic localized edge states are present in 2D layered perovskites. [1-3] The edge state facilitates extremely efficient electron-hole dissociation and long carrier lifetimes as much as those of 3D perovskites. However, the phenomenon has not been thoroughly investigated in a first-principles theoretical framework.
In this talk, we will discuss electronic structures and the origin of the edge states studied using first-principles calculations. Understanding the mechanism for edge state formation and their role in carrier separation will pave the way for controlling the edge states in future applications such as efficient photovoltaic devices and high-performance photodetectors.

[1] J.-C. Blancon et al., Science 355, 1288-1292 (2017).
[2] E. Shi et al., ACS Nano 13, 1635-1644 (2019).
[3] C. Zhao et al., J. Phys. Chem. Lett. 10, 3950-3954 (2019).