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The Role of Grain Boundaries on Ionic Defect Migration in Metal Halide Perovskites
Author(s) -
Phung Nga,
AlAshouri Amran,
Meloni Simone,
Mattoni Alessandro,
Albrecht Steve,
Unger Eva L.,
Merdasa Aboma,
Abate Antonio
Publication year - 2020
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201903735
Subject(s) - grain boundary , materials science , ionic bonding , chemical physics , crystallite , photoluminescence , charge carrier , thin film , halide , diffusion , crystallographic defect , ion , nanotechnology , crystallography , optoelectronics , inorganic chemistry , microstructure , composite material , metallurgy , chemistry , physics , organic chemistry , thermodynamics
Halide perovskites are emerging as revolutionary materials for optoelectronics. Their ionic nature and the presence of mobile ionic defects within the crystal structure have a dramatic influence on the operation of thin‐film devices such as solar cells, light‐emitting diodes, and transistors. Thin films are often polycrystalline and it is still under debate how grain boundaries affect the migration of ions and corresponding ionic defects. Laser excitation during photoluminescence (PL) microscopy experiments leads to formation and subsequent migration of ionic defects, which affects the dynamics of charge carrier recombination. From the microscopic observation of lateral PL distribution, the change in the distribution of ionic defects over time can be inferred. Resolving the PL dynamics in time and space of single crystals and thin films with different grain sizes thus, provides crucial information about the influence of grain boundaries on the ionic defect movement. In conjunction with experimental observations, atomistic simulations show that defects are trapped at the grain boundaries, thus inhibiting their diffusion. Hence, with this study, a comprehensive picture highlighting a fundamental property of the material is provided while also setting a theoretical framework in which the interaction between grain boundaries and ionic defect migration can be understood.