Interface modification in perovskite solar cells is a key factor for achieving high power conversion efficiency by suppressing electron-hole recombination and accelerating charge carrier extraction. Here, we use a series of phenyl ammonium derivatives, phenyl ammonium iodide (PAI), benzyl ammonium iodide (BAI), and phenyl ethyl ammonium iodide (PEAI), to modify the interface between methylammonium lead triiodide (MAPbI₃) perovskite and Spiro-OMeTAD as a hole transport layer in solar cell devices. The structural and optical properties of the perovskite films are studied and the results reveal the formation of two-dimensional perovskite interfacial layers on the surface of the MAPbI₃ film modified with PEAI and BAI whereas the MAPbI₃ layer modified with PAI gives an interface layer with slightly different properties compared to the two-dimensional perovskite. Impedance spectroscopy shows that the charge transport resistance of the interface engineered solar cells decreases when compared to pristine MAPbI₃. In addition, slower open-circuit voltage decay and longer carrier lifetime are also observed for the modified cells which in total lead to the improvement of the photovoltaic performance. The investigation therefore gives insight in the effect of interface modifications, and especially how different sizes of the molecular interface modifier results in different interface formation and characteristics.

钙钛矿太阳能电池中的界面改性是通过抑制电子-空穴复合并加速电荷载流子提取来实现高功率转换效率的关键因素。在这里，我们使用一系列苯基铵衍生物，碘化苯基铵（PAI），苄基碘化铵（BAI）和苯乙基碘化铵（PEAI）来修饰三碘化铅铵（MAPbI ₃）钙钛矿和Spiro- OMeTAD作为太阳能电池设备中的空穴传输层。研究了钙钛矿薄膜的结构和光学性质，结果揭示了在用PEAI和BAI改性的MAPbI ₃薄膜表面上形成了二维钙钛矿界面层，而MAPbI ₃与二维钙钛矿相比，用PAI改性的硅藻土层使界面层的性能略有不同。阻抗谱显示，与原始MAPbI ₃相比，界面工程太阳能电池的电荷传输电阻降低。另外，对于改性电池，还观察到较慢的开路电压衰减和较长的载流子寿命，这总体上导致光伏性能的改善。因此，该研究提供了界面修饰效果的见解，尤其是分子界面修饰剂的不同尺寸如何导致不同的界面形成和特性。