Estimation of carrier mobilities and recombination lifetime in halide perovskites films using the moving grating technique

Abstract

Pulsed excitation methods followed by time-resolved measurements have been questioned as a valid procedure to deduce transport properties of halide perovskites (HaPs). Measurements of both the majority and minority carrier?s phototransport properties, under illumination conditions as close as possible to one sun, are needed to obtain reliable information on recombination mechanisms. In this work, we show that the moving photocarrier grating technique (MGT) fulfills the above-mentioned conditions. In this method, both carriers mobilities and the common recombination lifetime are deduced from the DC short circuit current induced by the movement of an interference pattern along the sample surface. We show that the method, originally developed to measure the transport parameters of amorphous semiconductors, can be fully applied to HaPs films. We briefly describe the technique, we perform measurements as a function of the grating period and the light intensity, and we discuss the best approach to extract the transport parameters from MGT measurements. Finally, we find the exponents that describe the intensity dependence of the transport parameters of majority and minority carriers in a HaP sample.