Utilizing rubidium chloride as an effective and stable interface modification layer for high-efficiency solar cells

The presence of interface defects between the perovskite layer and the underlying substrate has a significant impact on the power conversion efficiency (PCE) and stability of perovskite solar cells (PSCs). SnO 2 thin films are employed in PSCs as electron transport layers to achieve high PCE. However, the significant lattice mismatch between SnO 2 and the perovskite material leads to a large number of uncoordinated defects at the interface between perovskite and substrate, resulting in recombination losses at the interface. In this study, rubidium chloride (RbCl) was introduced as the interface modification layer between the perovskite layer and the SnO 2 electron transport layer to enhance the PCE of PSCs. The research showed that the RbCl interface modification layer effectively passivated the under-coordinated defects of Sn ions and optimized the energy level alignment between the perovskite layer and the SnO 2 film. Moreover, the fabricated PSCs exhibited an open-circuit voltage of 1.11 V and a power conversion efficiency of 21.64%. Furthermore, the device maintained 80% of initial efficiency after storage for 30 days in an inert gas environment and 60% of the value after storage for 30 days in ambient air.