Dalian Institute of Chemical Technology published a non-lead perovskite nanocrystal carrier dynamics monograph

[ Instrument Network Instrument Development ] Recently, Han Keli, a researcher at the State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, was invited to publish a monograph entitled Charge-Carrier Dynamics of Lead-Free Halide Perovskite Nanocrystals.

Excited state carrier dynamics plays an important role in semiconductor luminescence and photoelectric conversion efficiency. In 2017, the team first studied the luminescence kinetics of Bi-based perovskite nanocrystals using femtosecond transient absorption spectroscopy at the international level, and found that the defect state has an ultra-fast (<20 ps) capture process for carriers. It is a key factor limiting its luminous efficiency (Angew. Chem. Int. Edit., 2017); further studies have found that there are two different time scale fast processes in non-lead double perovskite nanocrystals (Angew. Chem. Int. Edit., 2018); capture of carriers for surface defect states and photoinduced trap states, respectively (Angew. Chem. Int. Edit., 2019); by designing nanocrystals from indirect band gaps to direct band gaps, By passivating the surface defect state, the band edge luminous efficiency can be improved by more than 100 times (J. Am. Chem. Soc., 2018). At the same time, by regulating the electron-phonon coupling, the transition from the "dark" state to the "bright" state of the trapped excitons is realized, and finally a bright broad-spectrum white light emission can be realized (Sci. China Chem., 2019). These results indicate the potential application value of non-lead perovskite nanocrystals in the fields of display, illumination and the like. At the same time, the research results provide new ideas for guiding the design of new high-efficiency luminescent materials.

The team's research work on nano-crystal carrier dynamics of non-lead perovskite has received extensive attention from international counterparts. This article is the fourth time after the team (Acc. Chem. Res.), 2015 (Acc. Chem. Res.) and 2018 (Acc. Chem. Res.), on the Accounts of Chemical Research. Published a monograph article. The work was funded by the National Natural Science Foundation of China.