Recently, Han Keli, a researcher at the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences, and Tonu Pullerits, a professor at Lund University in Sweden, have made new progress in the research of perovskite microcrystalline photocurrent imaging. The related research results are published in the Journal of Physical Chemistry Express. (The Journal of Physical Chemistry Letters).
In recent years, perovskite materials have been widely used in research fields such as solar cells, photodetectors, and luminescent displays, and have made a series of breakthroughs. The good performance of perovskites is mainly due to their excellent carrier characteristics, such as The carrier mobility is high, the diffusion length is long, etc. However, the microscopic carrier dynamic behavior of the perovskite device under real working conditions is still unclear.
Recently, the team successfully prepared CH 3NH 3PbBr 3The perovskite microcrystalline photodetector and its high spatial resolution (1 micron, 1 micron = 10-6 m) photocurrent imaging technique were used to study the carrier dynamic behavior under an applied electric field. In the weak electric field, the carrier transport is a diffusion mechanism. Under a strong electric field, the carrier transport is a drift mechanism, and the carrier transport length is positively correlated with the applied electric field strength. Research also found in CH 3NH 3PbBr 3In perovskite single crystals, the distribution of defect states is also non-uniform and affects carrier transport length, which in turn affects device efficiency. The results show that the overall efficiency of the device can be improved by better controlling the distribution of defect states in the single crystal. .
The above work was funded by the National Natural Science Foundation of China.
