Observation of Hot Carrier Localization Affected by A Cations in Hybrid Perovskite

Organic-inorganic lead halide perovskites (OLHPs) have demonstrated exceptional properties in high-performance photoelectric devices. However, the impact of A-site cations, specifically formamidinium (FA) and methylammonium (MA), on the optoelectronic properties of OLHPs, particularly in the context of hot carrier utilization, remains a topic of debate. In this study, we propose a method to characterize hot carrier transportation by measuring hot carrier mobility and momentum-dependent transient photocurrent influenced by A-site cations in OLHPs. Our findings reveal that the direction of photon-drag current reverses with the substitution of the MA cation, suggesting strong localization of hot carriers by the MA cation dipole. Furthermore, the correlation between hot carrier photoconductivity and the electronic structure in different A-site cation samples indicates that hot carrier mobility in OLHPs can be reduced by more than 50% due to the influence of A-site cations.