Photo-electrochemical characterization of CH3NH3PbI3 Perovskite deposited on ZnO and TiO2 mesoporous structures during its dynamic restoration

Abstract

Methylammonium lead iodide, CH3NH3PbI3, perovskite solar cells are the subject of substantial research due to their high efficiency and inexpensive fabrication. The implementation of liquid electrolyte offers fast charge transport in the device. However, the hygroscopic nature of methylammonium iodide poses a challenge in contact with it. Here, we presented electrochemical characterization results of a perovskite-based three-probe device with a novel liquid electrolyte. This liquid electrolyte contained methylammonium iodide (MAI) in addition to the ionic carriers (lithium perchlorate) in isopropanol. MAI restored the degraded part of perovskite material dynamically. The X-ray diffraction analysis confirmed the constructive effect of this electrolyte on the morphology of perovskite crystalline structure. The performance of perovskite material deposited on two different mesoscopic structures, ZnO and TiO2, as active electrode in contact with this electrolyte was compared. The electrode coated with perovskite material on TiO2 demonstrated superior photovoltaic properties (i.e., higher photocurrent and photovoltage) compared to ZnO back contact. A detail electrochemical impedance spectroscopy study of both samples, in dark and light, suggested faster charge transport for the electrode with the TiO2 back contact. The consistency with the electrochemical results also indicated the stability of the perovskite material. Results from this study encourage making electrochemical perovskite solar cells with TiO2 as the electron collector with MAI-based electrolyte.