All-inorganic perovskite shows great potential for photovoltaic applications due to its excellent solar cell performance and atmospheric stability. Here, a CsPbI_2+xBr_1−x perovskite solar cell with a graded bandgap is explored using CsPbBrI₂ and CsPbI₃ quantum dots as component cells. Four strategies were pursued to boost the device performance. First, CsPbI₂Br film was fabricated as the main absorber, with the component cell showing remarkable power conversion efficiency (PCE) as high as 13.45%. Second, by Mn²⁺ substitution, SCN⁻ capping, and [(NH₂)₂CH]⁺ treatment, stable and high-mobility CsPbI₃ quantum dot (QD) film was attained. Third, a halide-ion-profiled heterojunction was designed at the CsPbBrI₂/CsPbI₃ QD interface to achieve proper band-edge bending as graded bandgap for improved carrier collection. Finally, the CsPbI₃ QD layer was optimized in the graded bandgap structure to achieve maximum overall light harvesting. As a result, the device achieved a PCE of 14.45%. This is the highest efficiency ever reported for inorganic perovskite solar cells.

全无机钙钛矿因其出色的太阳能电池性能和大气稳定性而显示出在光伏应用中的巨大潜力。在此，使用CsPbBrI ₂和CsPbI ₃量子点作为组分电池，探索了具有带隙级差的CsPbI _{2+ x} Br _{1 -x}钙钛矿太阳能电池。采取了四种策略来提高设备性能。首先，制造CsPbI ₂ Br薄膜作为主要吸收体，组成单元的功率转换效率（PCE）高达13.45％，显示出非凡的功率。第二，用Mn ²⁺的取代，SCN ^-封端，和[（NH ₂）₂ CH] ⁺通过处理，获得了稳定且高迁移率的CsPbI ₃量子点（QD）膜。第三，在CsPbBrI ₂ / CsPbI ₃ QD接口处设计了卤离子轮廓异质结，以实现适当的带边弯曲，作为梯度带隙用于改善载流子收集。最后，在渐变带隙结构中优化了CsPbI ₃ QD层，以实现最大的整体光收集。结果，该器件实现了14.45％的PCE。这是有报道的无机钙钛矿太阳能电池的最高效率。