Wide-bandgap (WBG) formamidinium–cesium (FA–Cs) hybrid lead iodide–bromide mixed perovskites (∼1.7 eV) have gained great attention with the potential of enabling highly efficient tandem photovoltaics when integrated with crystalline silicon and other low-bandgap solar cells. However, their power conversion efficiencies (PCEs) are still insufficient compared to their methylammonium (MA) counterparts, mainly owing to the high open-circuit voltage (V_OC) deficits (>0.43 V). Here, by incorporating rubidium iodide (RbI) in the FA_0.8Cs_0.2Pb(I_0.75Br_0.25)₃ perovskite precursor, the film crystallinity and bulk defects are significantly optimized. In addition, we propose an all-around interface engineering strategy sequentially constructing a surface heterojunction and using trioctylphosphine oxide (TOPO), which can significantly passivate grain boundaries and undercoordinated defects, as well as optimize the energy band. As a result, the target MA-free WBG n–i–p solar cells at 1.685 eV have achieved a record efficiency of 23.35% and a high V_OC of 1.30 V (with a record voltage deficit of 0.385 V). Most importantly, the unencapsulated solar cells also display impressive air storage stability, operating stability and thermal stability. Moreover, a PCE of 19.54% on a 1 cm² WBG solar cell and a PCE of 21.31% on a 0.04 cm² p–i–n inverted WBG solar cell are also demonstrated.

中文翻译：

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抑制无甲基铵宽带隙钙钛矿薄膜中的电荷复合，用于高性能和稳定的钙钛矿太阳能电池


宽带隙（WBG）甲脒-铯（FA-Cs）混合碘化铅-溴化物混合钙钛矿（∼1.7 eV）受到了极大的关注，当与晶体硅和其他低带隙太阳能集成时，其具有实现高效串联光伏发电的潜力。细胞。然而，与甲基铵 (MA) 同类产品相比，它们的功率转换效率 (PCE) 仍然不足，这主要是由于开路电压 (V _OC ) 不足 (>0.43 V)。这里，通过将碘化铷 (RbI) 掺入 FA _0.8 Cs _0.2 Pb(I _0.75 Br _0.25 ) ₃ （创纪录的电压赤字为 0.385五）。最重要的是，未封装的太阳能电池还表现出令人印象深刻的空气储存稳定性、工作稳定性和热稳定性。此外，还证明了 1 cm ² WBG 太阳能电池上的 PCE 为 19.54%，在 0.04 cm ² p-i-n 倒置 WBG 太阳能电池上的 PCE 为 21.31% 。