Recombination at high carrier density in methylammonium lead iodide studied using time-resolved microwave conductivity

Time-resolved microwave conductivity (TRMC) is a highly versatile method to rapidly evaluate the electronic properties of semiconducting compounds without the need to construct and optimize electronic devices. In this report, we study how bimolecular and Auger recombination mechanisms affect TRMC measurements. In particular, we investigate how recombination reduces the measured value of the TRMC figure-of-merit: ϕΣμ, at a high incident optical fluence. Using a numerical model, we calculate how these higher-order recombination processes reduce experimentally measured values of ϕΣμ relative to a regime of low carrier concentration with little recombination. By fitting this model to experimentally obtained data for the hybrid halide perovskite compound, methylammonium lead iodide, we are able to extract the bimolecular and Auger rate constants and provide a clear determination of the sum of the hole and electron mobilities for these films.