量子点
光电流
材料科学
晶界
载流子
钙钛矿(结构)
卤化物
微晶
化学物理
光电子学
纳米尺度
光电效应
粒度
纳米技术
结晶学
化学
复合材料
无机化学
微观结构
冶金
作者
Ghaida Alosaimi,Chien‐Yu Huang,Pankaj Sharma,Tom Wu,Jan Seidel
出处
期刊:Small
[Wiley]
日期:2023-02-20
卷期号:19 (20)
被引量:7
标识
DOI:10.1002/smll.202207220
摘要
Exceptional 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.
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