钙钛矿CsPbBr3中光生载流子的动力学行为

Dynamics of photo-excited carriers in CsPbBr3 perovskite

钙钛矿材料的光电性能十分优异,可应用于光电器件,且钙钛矿中光生载流子的动力学行为可以决定光电器件的性能.本研究利用泵浦探测瞬态吸收光谱研究CsPbBr 3量子点被激发后光生载流子的动力学行为,通过奇异值分解及全局拟合研究了CsPbBr 3量子点被光激发后的瞬态吸收光谱.实验结果表明,激子间的耦合会导致CsPbBr 3量子点的能带边沿发生红移,而Burstein-Moss效应会引起其能带边沿发生蓝移.结果同时揭示了CsPbBr 3量子点中光生载流子的动力学过程,以及与之对应的指前相关因子光谱,其中,热载流子的弛豫时间约为0.4 ps,10 ps和100 ps量级的衰减时间可归结为双激子以及带电激子的寿命,而纳秒量级的衰减时间可归结为激子的辐射复合.

Perovskite materials have outstanding photoelectric properties and can be used in optoelectronic devices.The dynamics of photo-excited carriers in the perovskite can determine the photoelectric properties of these optoelectronic devices.In this paper,the dynamics of photo-excited carriers in CsPbBr 3 quantum dots is studied via pump-probe transient absorption spectroscopy,and the transient absorption spectrum is analyzed by singular value decomposition and global fitting.The results show the red-shift and blue-shift of the band edge can be attributed to the exciton-exciton interaction and Burstein-Moss effect,respectively.The results also reveal the dynamics and corresponding preexponential factors spectra of photo-excited carriers.The relaxation time of hot carriers is 0.4 ps,decay times in the order of ten picoseconds and hundred picoseconds can be attributed to the lifetime of both double excitons and charged excitons,while the decay time on the order of nanoseconds can be attributed to the radiative recombination of excitons.