Nowadays, the MA-FA mixed-cation perovskite solar cells (PSCs), demonstrating much higher stability than that of single-cation MAPbI₃ or FAPbI₃, are still encountering a low-efficiency issue. The main reason is that there existing a lot of defects in SnO₂ electron transport layers (ETLs) and perovskite absorbers. Herein, we develop a synergistic strategy of Rubidium Chloride (RbCl) doping and 4-tert-butylbenzylammonium iodide (tBBAI) passivation to fabricate high-performance MA_xFA_1-xPbI₃ mixed-cation PSCs. The alkali halide RbCl is first selected as a novel doping additive to regulate the film properties of SnO₂ and perovskites. Research shows that the negative Cl^- ions can combine with uncoordinated Sn⁴⁺ ions due to their strong bonding ability, which can passivate the oxygen-vacancy-related defects and enhance the charge transport of SnO₂ ETLs. Meanwhile, the doped Rb⁺ and Cl^- ions may diffuse into perovskite lattices to promote grain growth and reduce the defects of perovskites. Besides, we employ an organic halide salt tBBAI to passivate perovskites and suppress surface defects. Results of deep level transient spectroscopy (DLTS) indicate that SnO₂ and SnO₂-RbCl based devices have deeper hole traps and large trap densities (ΔE = 0.92 eV, N_T = 1.10 × 10¹⁶ cm⁻³; ΔE = 0.93 eV, N_T = 2.16 × 10¹⁵ cm⁻³); while tBBAI-treated SnO₂-RbCl-based devices own a shallower hole trap and a smaller trap density (ΔE = 0.72 eV, N_T = 2.44 × 10¹³ cm⁻³); and the corresponding I_Pb and I_(MA/FA) antisite defeats are also identified. Therefore, our synergistic strategy is effectively able to reduce the defect density and suppress the non-radiative recombination. Consequently, the best-performance MA_0.85FA_0.15PbI₃ PSCs achieve an impressive power conversion efficiency (PCE) of 22.54% with a large open circuit voltage (V_oc) of 1.16 V, which are by far the highest values of MA_0.85FA_0.15PbI₃ mixed-cation PSCs.

如今，MA-FA 混合阳离子钙钛矿太阳能电池 (PSC) 比单阳离子 MAPbI ₃或 FAPbI ₃表现出更高的稳定性，但仍然遇到低效率问题。主要原因是SnO ₂电子传输层(ETLs)和钙钛矿吸收层存在很多缺陷。在此，我们开发了氯化铷 (RbCl) 掺杂和 4-叔丁基苄基碘化铵 (tBBAI) 钝化的协同策略，以制造高性能 MA _x FA _1-x PbI ₃混合阳离子 PSC。_{首次选择碱金属卤化物 RbCl 作为新型掺杂添加剂来调节 SnO 2}的薄膜性能和钙钛矿。研究表明，Cl ^{-负离子具有很强的键合能力，可以与未配位的Sn 4+}离子结合，钝化与氧空位相关的缺陷，增强SnO ₂ ETLs的电荷传输。同时，掺杂的Rb ⁺和Cl ^-离子可以扩散到钙钛矿晶格中以促进晶粒生长并减少钙钛矿的缺陷。此外，我们使用有机卤化物盐 tBBAI 来钝化钙钛矿并抑制表面缺陷。深能级瞬态光谱 (DLTS) 结果表明，基于 SnO ₂和 SnO ₂ -RbCl 的器件具有更深的空穴陷阱和大的陷阱密度 (Δ E = 0.92 eV, N _T  = 1.10 × 10 ¹⁶ cm ⁻³ ; ΔE  = 0.93 eV, N _T  = 2.16 × 10 ¹⁵ cm ⁻³ ); 而经过tBBAI处理的SnO ₂ -RbCl基器件具有更浅的空穴陷阱和更小的陷阱密度（ΔE  = 0.72 eV, N _T  = 2.44 × 10 ¹³ cm ⁻³）；以及相应的 I _Pb和 I _(MA/FA)还确定了反站点失败。因此，我们的协同策略能够有效地降低缺陷密度并抑制非辐射复合。因此，性能最佳的 MA _0.85 FA _0.15 PbI ₃ PSC 实现了令人印象深刻的 22.54% 的功率转换效率 (PCE) 和 1.16 V 的大开路电压 ( V _{oc )，这是迄今为止 MA 0.85} FA的最高值_0.15 PbI ₃混合阳离子PSC。