Electronic properties of Pb-I deficient lead halide perovskites
Abstract
The electronic structure evolution of deficient halide perovskites with a
general formula $(A,A')_{1+x}M_{1-x}X_{3-x}$ was investigated using the density
functional theory. The focus is placed on characterization of changes in the
band gap, band alignment, effective mass, and optical properties of deficient
perovskites at various concentrations of defects. We uncover unusual electronic
properties of the defect corresponding to a $M\!-\!X$ vacancy filled with an
$A'$ cation. This defect "repels" electrons and holes producing no trap states
and, in moderate quantities ($x\le0.1$), does not hinder charge transport
properties of the material. This behavior is rationalized using a confinement
model and provides an additional insight to the defect tolerance of halide
perovskites.
Authors
Zheng C; Rubel O; Kepenekian M; Rocquefelte X; Katan C