Modulation of Charge Recombination in CsPbBr3 Perovskite Films with Electrochemical Bias.

ABSTRACT

The charging of a mesoscopic TiO2 layer in a metal halide perovskite solar cell can influence the overall power conversion efficiency. By employing CsPbBr3 films deposited on a mesoscopic TiO2 film, we have succeeded in probing the influence of electrochemical bias on the charge carrier recombination process. The transient absorption spectroscopy experiments conducted at different applied potentials indicate a decrease in the charge carrier lifetimes of CsPbBr3 as we increase the potential from -0.6 to +0.6 V vs Ag/AgCl. The charge carrier lifetime increased upon reversing the applied bias, thus indicating the reversibility of the photoresponse to charging effects. The ultrafast spectroelectrochemical experiments described here offer a convenient approach to probe the charging effects in perovskite solar cells.