Modulation of Charge Recombination in CsPbBr(3) Perovskite Films with Electrochemical Bias

[Image: see text] The charging of a mesoscopic TiO(2) layer in a metal halide perovskite solar cell can influence the overall power conversion efficiency. By employing CsPbBr(3) films deposited on a mesoscopic TiO(2) 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 CsPbBr(3) 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.