Defect passivation engineering of wide-bandgap perovskites for high-performance solar cells

Wide-bandgap (WBG) mixed-halide perovskite solar cells (PVSCs) exhibit a wide range of applicability, such as tandem photovoltaics (PVs), underwater PVs, space PVs, and building-integrated photovoltaics (BIPVs). However, the state-of-the-art WBG mixed-halide PVSCs still suffer from phase segregation and large open-circuit voltage (Voc) loss, which significantly limit the overall power conversion efficiency of devices. A dominant source of these limitations is the presence of defects within the mixed-halide perovskite lattice structure and at interfaces between the perovskite and carrier transport layers (CTLs). In response, various device engineering strategies have been implemented to passivate the defects and improve device performance. Therefore, in this comprehensive review, different types of defects inherent in WBG mixed-halide perovskites were firstly described, followed by their detrimental effects on perovskite materials and corresponding device performance. Furthermore, several device engineering strategies to passivate the defects at perovskite buried interface, perovskite bulk, and perovskite surface had been summarized, respectively. These defect passivation schemes provided a forward-oriented perspective on forthcoming strategies for WBG mixed-halide PVSCs. These strategies not only offered valuable guidance for realizing enhanced efficiency but also improved the phase stability of WBG mixed-halide PVSCs in the pursuit of high-performance PV technology. This article provides a comprehensive review of the strategies for passivating defects in wide-bandgap perovskite solar cells.