Affiliation:
1. Department of Chemistry Southern University of Science and Technology Shenzhen Guangdong 518055 P. R. China
2. Department of Materials Science and Engineering The University of Texas at Dallas Richardson TX 75080 USA
3. Department of Electrical and Electronic Engineering Southern University of Science and Technology Shenzhen Guangdong 518055 P. R. China
Abstract
AbstractIon diffusion is a fundamentally important process in understanding and manipulating the optoelectronic properties of semiconductors. Most current studies on ionic diffusion have been focusing on perovskite polycrystalline thin films and nanocrystals. However, the random orientation and grain boundaries can heavily interfere with the kinetics of ion diffusion, where the experimental results only reveal the average ion exchange kinetics and the actual ion diffusion mechanisms perpendicular to the direction of individual crystal facets remain unclear. Here, the anion (Cl, I) diffusion anisotropy on (111) and (100) facets of CsPbBr3 single crystals is demonstrated. The as‐grown single crystals with (111) and (100) facets exhibit anisotropic growth with different halide incorporation, which lead to different resulting optoelectronic properties. Combined experimental characterizations and theoretical calculations reveal that the (111) CsPbBr3 shows a faster anion diffusion behavior compared with that of the (100) CsPbBr3, with a lower diffusion energy barrier, a larger built‐in electric field, and lower inverse defect formation energy. The work highlights the anion diffusion anisotropic mechanisms perpendicular to the direction of individual crystal facets for optimizing and designing perovskite optoelectronic devices.
Funder
National Natural Science Foundation of China
Subject
Biomaterials,Biotechnology,General Materials Science,General Chemistry