LAUSR

Recently organic–inorganic lead-halide perovskite nanoparticles (NPs) have been attractive as low-cost and high-conversion-efficient solar cells and light-emitting diode. The generation of the exciton and dissociation into free carriers are quite important for primary photoelectric conversion processes. In this study, we have examined the initial exciton dynamics of CH3NH3PbBr3 (MAPbBr3) NPs by femtosecond transient absorption spectroscopy and picosecond time-resolved luminescence spectroscopy. The ultrafast exciton quenching with a time constant of 200 fs was observed, which may be related with longitudinal optical phonon and/or lurching motion of MA cation in the excited state. In addition, higher electronic state with a short lifetime was clearly detected by the excitation intensity dependence of time-resolved luminescence and transient absorption spectra. These findings of MAPbBr3 NPs are very important not only for understanding the generation of charge carrier but also for constructing the high-effi...