Nonlinear photocarrier recombination dynamics in mixed-halide CH₃NH₃Pb(I₁₋ <i> _x </i>Br<i> _x </i>)₃ perovskite thin films

Abstract

Mixed-halide perovskites, whose bandgap energies can be widely controlled through choice of composition, are promising for various optoelectronic applications. Herein, we report the photocarrier recombination dynamics in mixed-halide CH3NH3Pb(I1−xBrx)3 perovskite films with different Br contents. We observed small changes in the single-carrier trapping rate with respect to the Br content. In contrast, the two-carrier radiative and three-carrier Auger recombination rates increased significantly with the Br content. These increases in the multicarrier recombination rates likely originated from the enhancement of the Coulomb interactions between electrons and holes caused by incorporating Br. Our findings are useful for designing mixed-halide perovskite-based optoelectronic devices.