TY - JOUR AU - Lin, Ze Qing AU - Lian, Hui Jun AU - Ge, Bing AU - Zhou, Ziren AU - Yuan, Haiyang AU - Hou, Yu AU - Yang, Shuang AU - Yang, Hua Gui PY - 2021/08/17 Y2 - 2024/03/28 TI - Mediating the Local Oxygen-Bridge Interactions of Oxysalt/Perovskite Interface for Defect Passivation of Perovskite Photovoltaics JF - Nano-Micro Letters JA - Nano-Micro Lett VL - 13 IS - SE - Articles DO - 10.1007/s40820-021-00683-7 UR - https://nmlett.org/index.php/nml/article/view/943 SP - 177 AB - <p>Passivation, as a classical surface treatment technique, has been widely accepted in start-of-the-art perovskite solar cells (PSCs) that can effectively modulate the electronic and chemical property of defective perovskite surface. The discovery of inorganic passivation compounds, such as oxysalts, has largely advanced the efficiency and lifetime of PSCs on account of its favorable electrical property and remarkable inherent stability, but a lack of deep understanding of how its local configuration affects the passivation effectiveness is a huge impediment for future interfacial molecular engineering. Here, we demonstrate the central-atom-dependent-passivation of oxysalt on perovskite surface, in which the central atoms of oxyacid anions dominate the interfacial oxygen-bridge strength. We revealed that the balance of local interactions between the central atoms of oxyacid anions (e.g., N, C, S, P, Si) and the metal cations on perovskite surface (e.g., Pb) generally determines the bond formation at oxysalt/perovskite interface, which can be understood by the bond order conservation principle. Silicate with less electronegative Si central atoms provides strong O-Pb motif and improved passivation effect, delivering a champion efficiency of 17.26% for CsPbI<sub>2</sub>Br solar cells. Our strategy is also universally effective in improving the device performance of several commonly used perovskite compositions.</p><p>Highlights:</p><p>1 Oxyacid anions (NO<sub>3</sub><sup>−</sup>, SO<sub>4</sub><sup>2−</sup>, CO<sub>3</sub><sup>2−</sup>, PO<sub>4</sub><sup>3−</sup> and SiO<sub>3</sub><sup>2−</sup>) were investigated both theoretically and experimentally about their passivation effect on CsPbI<sub>2</sub>Br perovskite interface.<br>2 Adjustment of oxysalt layer thickness can optimize the surface band position that could be beneficial for electronic band alignment at perovskite/transport layer interface.<br>3 Using silicate as a passivator, the CsPbI<sub>2</sub>Br solar cells achieved a PCE of 17.26% with an open-circuit voltage of 1.36 V. This strategy is also effective for organic-inorganic perovskite solar cells.</p> ER -