Affiliation:
1. Department of Chemistry Faculty of Science Taif University Taif 21944 Saudi Arabia
2. School of Materials Science and Engineering UNSW Australia Sydney NSW 2052 Australia
3. ARC Centre of Excellence in Future Low‐Energy Electronics Technologies (FLEET) UNSW Sydney Sydney 2052 Australia
4. College of Science and Engineering Flinders University Bedford Park Adelaide SA 5042 Australia
Abstract
AbstractExceptional electronic, optoelectronic, and sensing properties of inorganic Cs‐based perovskites are significantly influenced by the defect chemistry of the material. Although organic halide perovskites that have a polycrystalline structure are heavily studied, understanding of the defect properties at the grain boundaries (GB) of inorganic Cs‐based perovskite quantum dots (QDs) is still limited. Here, morphology‐dependent charge carrier dynamics of CsPbBr3 quantum dots at the nanoscale by performing scanning probe microscopy of thermally treated samples are investigated. The grain boundaries of defect‐engineered samples show higher surface potential than the grain interiors under light illumination, suggesting an effective role of GBs as charge collection and transport channels. The lower density of crystallographic defects and lower trap density at GBs specifically of heat‐treated samples cause insignificant dark current, lower local current hysteresis, and higher photocurrent, than the control samples. It is also shown that the decay rate of surface photovoltage of the heated sample is quicker than the control sample, which implies a considerable impact of ion migration on the relaxation dynamic of photogenerated charge carriers. These findings reveal that the annealing process is an effective strategy to control not only the morphology but also the optoelectrical properties of GB defects, and the dynamic of ion migration. Understanding the origin of photoelectric activity in this material allows for designing and engineering optoelectronic QD devices with enhanced functionality.
Funder
Australian Research Council
Subject
Biomaterials,Biotechnology,General Materials Science,General Chemistry
Cited by
7 articles.
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