Unexpectedly Strong Auger Recombination in Halide Perovskites

Abstract

The emergence of halide perovskites for photovoltaic applications has triggered great interest in these materials for solidâ state light emission. Higher order electronâ hole recombination processes can critically affect the efficiency of such devices. In the present work, the Auger recombination coefficients are computed in the prototypical halide perovskite, CH3NH3PbI3 (MAPbI3), using firstâ principles calculations. It is demonstrated that Auger recombination is responsible for the exceptionally high thirdâ order recombination coefficient observed in experiment. The large Auger coefficient is attributed to a coincidental resonance between the bandgap and interband transitions to a complex of higherâ lying conduction bands. Additionally, it is found that the distortions of PbI6 octahedra contribute significantly to the high Auger coefficient, offering potential avenues for materials design.The unexpectedly high thirdâ order recombination coefficient in halide perovskites is identified to stem from Auger recombination. Firstâ principles calculations show that the large Auger coefficient originates from a coincidental resonance as well as from distortions in the metalâ halide lattice. These insights point to avenues for improved materials design.