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.

界面工程推动了 p-i-n 钙钛矿太阳能电池 (PSC) 的最新发展，其自组装单层空穴传输层 (SAM-HTL) 使溶液处理的 PSC 几乎无损接触，从而实现了最高的功率转换效率。 PCE）至今。基底界面对于共蒸发 PSC 的生长和质量尤其重要。然而，由于钙钛矿与膦酸官能团的相互作用尚未得到充分研究，采用 SAM-HTL 进行共蒸发钙钛矿吸收剂变得复杂。在这项工作中，我们重点介绍了暴露的膦酸官能团如何影响共蒸发钙钛矿及其所得 PCE 的初始相和最终块状晶体结构。所探索的表面相互作用是通过与界面碘的氢键介导的，导致甲脒碘化物吸附增加、钙钛矿结构持续变化以及块状α-FAPbI ₃ 的稳定，假设是由于动力学捕获。我们的结果凸显了利用基底来增强对共蒸发钙钛矿生长的控制的潜力。