Quasi-2D perovskites passivate the perovskite surface and improve the lifetime of perovskite solar cells. However, their detailed surface structures have never been reported. We studied the surfaces of the solution-processed quasi-2D PEA_2m MA _n−2m Pb _n I_3n (PEA: C₆H₅CH₃CH₂NH₃, MA: CH₃NH₃) perovskites as well as the 2D perovskite formed on top of 3D MAPbI₃ with the thicknesses relevant to practical solar cell (n≈400) using ultraviolet photoelectron and metastable-atom electron spectroscopies. We confirmed that PEA segregates to the surface and that the phenyl group (C₆H₅) covers the outermost surface of the quasi-2D perovskite. We discuss plausible structures from the concentration dependence of PEA.

准2D钙钛矿钝化钙钛矿表面并提高钙钛矿太阳能电池的寿命。但是，尚未报道其详细的表面结构。我们研究了固溶的准2D PEA _{2 m} MA _{n -2 m} Pb _n I _{3 n}（PEA：C ₆ H ₅ CH ₃ CH ₂ NH ₃，MA：CH ₃ NH ₃）钙钛矿的表面以及在3D MAPbI ₃顶部形成的2D钙钛矿，其厚度与实际太阳能电池（n ≈400）使用紫外光电子和亚稳原子电子光谱学。我们确认，PEA偏析在表面，并且苯基（C ₆ H ₅）覆盖了准2D钙钛矿的最外表面。我们从PEA的浓度依赖性讨论合理的结构。