Shallow traps-induced ultra-long lifetime of metal halide perovskites probed with light-biased time-resolved microwave conductivity

Abstract

Metal halide perovskites have emerged as promising candidates for next-generation optoelectronics. However, the present understanding of their recombination processes and trap states within the devices are still limited, which is also inevitable in the state-of-the-art perovskite solar cells with multiple passivation strategies and various additives involved. Recent works have also demonstrated that metal cations incorporated perovskites could potentially reduce the non-radiative losses and improve the device performance to some extent. However, the underlying “doping” mechanism is not clear. In this work, we systematically investigated the trap-induced ultra-long carrier lifetime of the metal cation incorporated perovskites and found that some specific cations could extend the carrier lifetime up to ∼100 μs, which could be correlated with the formation of shallow trap states. In addition, such shallow trap-mediated charge dynamics could be effectively probed with light-biased time-resolved microwave conductivity technique, which provides additional information to conventional time-resolved photoluminescence.