Abstract The severe degradation and limited optoelectronic performance in water is the Achilles' heel of hybrid organic-inorganic halide perovskite materials, which prevents their further industrial deployment in hostile conditions. In this manuscript, we propose a new molecular dye bearing a dicyano group to improve the water stability and optoelectronic properties of the halide perovskite/TiO2 film. The halide perovskite-based photoelectrochemical setup bearing the dicyano anchor-based dye, 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran, witnesses a significant enhancement in the photocurrent generated by the halide perovskite CH3NH3PbI3-based film in aqueous solution under the visible light irradiation. Such enhanced optoelectronic performance is accompanied with a much improved stability of the halide perovskite film in water. The first-principles calculations suggest that the molecular dye bearing the dicynao anchor not only adsorbs on the TiO2 substrate, but also strongly interacts with the halide perovskite surfaces; therefore, the bifunctional dicyano anchor could stabilize the CH3NH3PbI3/TiO2 interfacial structure and improve the optoelectronic performance and stability of the halide perovskite electrode. This study benefits the development of the dye-sensitized perovskite materials for the halide-perovskite-based energy devices such as solar cells and water-splitting systems.

中文翻译：

---

双氰基染料改进的卤化物钙钛矿/TiO2薄膜的光电化学和第一性原理研究

摘要 在水中的严重退化和有限的光电性能是混合有机-无机卤化物钙钛矿材料的致命弱点，这阻碍了它们在恶劣条件下的进一步工业部署。在这份手稿中，我们提出了一种带有二氰基的新型分子染料，以提高卤化物钙钛矿/TiO2 薄膜的水稳定性和光电性能。带有二氰基锚基染料 4-(二氰基亚甲基)-2-甲基-6-(4-二甲基氨基苯乙烯基)-4H-吡喃的基于卤化物钙钛矿的光电化学装置见证了卤化物钙钛矿 CH3NH3PbI3 产生的光电流显着增强- 在可见光照射下水溶液中的薄膜。这种增强的光电性能伴随着卤化物钙钛矿薄膜在水中的稳定性大大提高。第一性原理计算表明，带有dicynao锚的分子染料不仅吸附在TiO2基底上，而且与卤化物钙钛矿表面强烈相互作用；因此，双功能双氰基锚可以稳定 CH3NH3PbI3/TiO2 界面结构，提高卤化物钙钛矿电极的光电性能和稳定性。这项研究有利于染料敏化钙钛矿材料的开发，用于基于卤化物-钙钛矿的能源设备，如太阳能电池和水分解系统。但也与卤化物钙钛矿表面强烈相互作用；因此，双功能双氰基锚可以稳定 CH3NH3PbI3/TiO2 界面结构，提高卤化物钙钛矿电极的光电性能和稳定性。这项研究有利于染料敏化钙钛矿材料的开发，用于基于卤化物-钙钛矿的能源设备，如太阳能电池和水分解系统。但也与卤化物钙钛矿表面强烈相互作用；因此，双功能双氰基锚可以稳定 CH3NH3PbI3/TiO2 界面结构，提高卤化物钙钛矿电极的光电性能和稳定性。这项研究有利于染料敏化钙钛矿材料的开发，用于基于卤化物-钙钛矿的能源设备，如太阳能电池和水分解系统。