In the past few years, organic–inorganic halide perovskites have rapidly emerged as promising materials for photovoltaic applications, but simultaneously achieving high performance and long-term stability has proved challenging. Here, we show a one-step solution-processing strategy using phosphonic acid ammonium additives that results in efficient perovskite solar cells with enhanced stability. We modify the surface of methylammonium lead triiodide (CH₃NH₃PbI₃) perovskite by spin-coating its precursor solution in the presence of butylphosphonic acid 4-ammonium chloride. Morphological, structural and elemental analyses show that the phosphonic acid ammonium additive acts as a crosslink between neighbouring grains in the perovskite structure, through strong hydrogen bonding of the –PO(OH)₂ and –NH₃⁺ terminal groups to the perovskite surface. The additives facilitate the incorporation of the perovskite within a mesoporous TiO₂ scaffold, as well as the growth of a uniform perovskite layer at the surface, enhancing the material's photovoltaic performance from 8.8 to 16.7% as well as its resistance to moisture.

在过去的几年中，有机-无机卤化物钙钛矿已迅速成为光伏应用的有前途的材料，但同时实现高性能和长期稳定性已被证明具有挑战性。在这里，我们展示了使用膦酸铵添加剂的一步法溶液处理策略，该策略可产生具有增强稳定性的有效钙钛矿太阳能电池。我们修改了甲基碘化三碘化铅（CH ₃ NH ₃ PbI ₃通过在丁基膦酸4-铵的存在下旋涂其前体溶液来制备钙钛矿。形态，结构和元素分析表明，膦酸铵添加剂可通过–PO（OH）₂和–NH ₃ ⁺端基与钙钛矿表面的强氢键作用，作为钙钛矿结构中相邻晶粒之间的交联键。添加剂有助于将钙钛矿掺入中孔TiO ₂支架中，并促进表面均匀钙钛矿层的生长，从而将材料的光伏性能从8.8提高到16.7％，并提高其耐湿性。