Ultrafast photoinduced carrier dynamics in single crystalline perovskite films

Photoinduced carrier dynamics of CsPbBr₃ single crystalline perovskite films were studied using femtosecond time-resolved transient absorption (TA) microscopy with a sub-micron spatial resolution. TA spectra of the internal area and boundary of perovskite films were obtained, respectively, and photoinduced carrier dynamic processes including hot carrier cooling, defect state trapping and carrier recombination were elucidated by singular value decomposition (SVD) and global fitting analysis of the TA spectra. Compared with the internal region, excited state absorption induced by the defects at the boundary was observed, and the shorter lifetimes of photoinduced carriers were attributed to the large number of defect states accelerating the non-radiative recombination of carriers. This work may provide further understanding about the influence of boundary defects on the performance of single crystalline perovskite devices.