Are solution processed CsPbI3 perovskite nanocrystalline films similar to traditional crystalline semiconductors?

Abstract We use ultrafast photocurrent spectroscopy with a sub-25 picosecond resolution to address a long-standing question in emergent perovskite materials: are solution-processed CsPbI3 perovskites nanocrystal films similar to their counterparts semiconductors including GaAs and Si? Prior to carrier trapping, all semiconductors show similar transition of transport mechanism from the band-like transport due to the longitudinal optical (LO) phonon scattering in the higher temperature region to a combination of band-like and hopping transport mechanisms in the lower temperature region. The critical difference is that CsPbI3 demonstrate the strongest carrier-LO phonon interaction among all semiconductors, most likely due to the unique cation-halogen bond arrangements within the highly symmetric lattice structure. This ultrafast dynamics work establish a foundation of fundamental carrier transport understating for perovskite optoelectronics.