Electron beam evaporated SiO2 interfacial layer for improved CsPbI3-xBrx perovskite solar cells

Abstract

Perovskite solar cells (PSCs) have demonstrated significant advances in efficiency, yet issues such as interfacial defects and poor long-term stability remain significant barriers to their practical application. All-inorganic CsPbI_3-xBr_x perovskites exhibit enhanced thermal and photostability, but still suffer from severe interfacial non-radiative recombination, limiting overall device performance. In this work, we introduced a SiO₂ interfacial modification layer prepared via electron beam evaporation between the TiO₂ electron transport layer and the perovskite absorber. The introduced SiO₂ layer significantly improved surface wettability, enabling uniform crystallization of the perovskite films, and efficiently passivated interfacial defects, resulting in reduced interfacial recombination and enhanced photovoltaic performance. The optimized SiO₂-modified device achieved a power conversion efficiency (PCE) of 13.3 %, a notable improvement over the 10.4 % of the control device, primarily due to enhanced open-circuit voltage and fill factor. Moreover, these SiO₂-modified PSCs exhibited significantly enhanced ambient stability without encapsulation. This study highlights electron beam evaporation as a simple, cost-effective, and promising approach for improving the efficiency and stability of CsPbI_3-xBr_x perovskite solar cells.