Investigation of p-type SnO films served as a potential hole-transporting material for highly efficient perovskite solar cells

As an essential component of perovskite solar cells (PSCs), the design of hole transport materials (HTMs) has always been a topic of interest in the photovoltaic community. In this work, p-type tin monoxide (SnO) films are grown by electron beam evaporation to investigate the influence of substrate temperature and deposition time on their properties. The film crystallization and preferred growth orientation of (001) showed prominent enhancement with the increase in substrate temperature. The prolongation of deposition time witnessed changes in grain morphology from nanoparticles to nanosheets. Hall measurements revealed that the film deposited at 200 °C showed the lowest resistivity, the maximum carrier concentration, and the lowest carrier mobility. Using these films as HTMs, the performance of PSCs based on caesium lead iodide perovskites (CsPbI3) was analyzed theoretically and experimentally, and high open-circuit voltage (VOC) of 1.16 V is obtained. With the increase of the substrate temperature, the power conversion efficiency of PSCs is decreased due to the decreased hole concentration. The results suggest that SnO film deposited at low substrate temperature holds promise for facilitating high-performance PSCs as HTMs.