Interfacial engineering has fueled recent development of p-i-n perovskite solar cells (PSCs), with self-assembled monolayer-based hole-transport layers (SAM-HTLs) enabling almost lossless contacts for solution-processed PSCs, resulting in the highest achieved power conversion efficiency (PCE) to date. Substrate interfaces are particularly crucial for the growth and quality of co-evaporated PSCs. However, adoption of SAM-HTLs for co-evaporated perovskite absorbers is complicated by the underexplored interaction of such perovskites with phosphonic acid functional groups. In this work, we highlight how exposed phosphonic acid functional groups impact the initial phase and final bulk crystal structures of co-evaporated perovskites and their resultant PCE. The explored surface interaction is mediated by hydrogen bonding with interfacial iodine, leading to increased formamidinium iodide adsorption, persistent changes in perovskite structure, and stabilization of bulk α-FAPbI3, hypothesized as being due to kinetic trapping. Our results highlight the potential of exploiting substrates to increase control of co-evaporated perovskite growth.

中文翻译：

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了解和利用膦酸官能团和共蒸发钙钛矿之间的界面相互作用


界面工程推动了 p-i-n 钙钛矿太阳能电池 （PSC） 的最新发展，自组装的基于单层的空穴传输层 （SAM-HTL） 使溶液处理的 PSC 几乎无损接触，从而实现了迄今为止最高的功率转换效率 （PCE）。底物界面对于共蒸发 PSC 的生长和质量尤为重要。然而，由于这种钙钛矿与膦酸官能团的相互作用未得到充分探索，因此将 SAM-HTL 用于共蒸发钙钛矿吸收剂变得复杂。在这项工作中，我们强调了暴露的膦酸官能团如何影响共蒸发钙钛矿的初始阶段和最终本体晶体结构及其产生的 PCE。探索的表面相互作用是由氢键与界面碘介导的，导致碘化甲脒吸附增加，钙钛矿结构的持续变化以及本体 α-FAPbI3 的稳定化，假设是由于动力学捕获。我们的结果强调了利用衬底来加强对共蒸发钙钛矿生长的控制的潜力。