Multi functional ionic Ru(bpy)₃(PF₆)₂ assisted preparation of perovskite solar cell with over 19% and superior stability

Abstract The global community is striving to advance the development of emerging perovskite solar cells (PSCs). It has been demonstrated that the utilization of passivators is an effective approach to enhance the photoelectric conversion efficiency and long-term stability of PSCs, thus attracting increasing attention to organic passivators. All-inorganic CsPbI 3 PSCs play a crucial role in the next-generation photovoltaic technology due to their unique optical bandgap and excellent light absorption properties. However, due to its poor stability, CsPbI 3− x Br x halide hybrid perovskite has been proposed. The spin-coating film formation method leads to the presence of a large number of vacancy defects in the film, which poses a significant challenge to the commercialization of CsPbI 3− x Br x perovskite films. Therefore, in this study, a novel passivator, Ru(bpy) 3 (PF 6 ) 2 (TRH), was introduced. By introducing the passivator, the photoelectric conversion efficiency of PSCs in air was improved, there by optimizing the device performance. After the addition of the passivator, [Ru(bpy) 3 ] 2+ filled the defects on the surface of the film, while the free PF 6 - ions passivated the negatively charged halide vacancies. The fluorine atoms effectively prevented the entry of water molecules in the air. As a result, the optimized CsPbI 3− x Br x film exhibited a more compact morphology, a lower defect state density, and better carrier transport performance. Eventually, the champion device achieved a photoelectric conversion efficiency of 19.47%, and even after being placed at an ambient temperature of 25 °C–30°C and a humidity of 30%–40% for 150 d, its efficiency remained above 85% of the initial efficiency of the device.