Cesium lead iodide (CsPbl₃) is a promising photo-absorber for perovskite photovoltaics due to its high thermal stability and relatively small bandgap. However, there are many defects in solution processed polycrystalline CsPbl₃ films especially at the grain boundaries (GBs), which limit the power conversion efficiency (PCE) of CsPbl₃ solar cells. in this work, we introduced CsPbBr₃ quantum dots (QDs) on top of the CsPbl₃ film to passivate the defects. As CsPbBr₃ QDs have a small size and a similar crystal structure as the CsPbl₃, they are excellent modifiers to fill in the GBs and heal the defects. Moreover, we find there is an anion exchange reaction between the CsPbBr₃ QDs and CsPbl₃ films, which is evidenced by photoluminescence spectra and grazing incidence X-ray diffraction patterns. The QDs treated films show enhanced carrier lifetime and reduced defect density. Additionally, the ligands on CsPbBr₃ QDs increase the hydrophobicity of the films. As a result, the QDs treated CsPbl₃ solar cells prepared at high temperature obtain PCEs exceeding 16% with high stability.

由于其高热稳定性和相对较小的带隙，碘化铯铅 (CsPbl ₃ ) 是一种很有前途的钙钛矿光伏光吸收剂。然而，溶液加工的多晶CsPbl ₃薄膜存在许多缺陷，特别是在晶界（GBs）处，这限制了CsPbl ₃太阳能电池的功率转换效率（PCE）。在这项工作中，我们在 CsPbl ₃薄膜顶部引入了 CsPbBr ₃量子点 (QD)以钝化缺陷。由于 CsPbBr ₃ QD 具有小尺寸和与 CsPbl ₃相似的晶体结构，它们是填补 GB 和修复缺陷的出色修饰符。此外，我们发现 CsPbBr ₃ QD 和 CsPbl ₃薄膜之间存在阴离子交换反应，光致发光光谱和掠入射 X 射线衍射图证明了这一点。量子点处理的薄膜显示出增强的载流子寿命和降低的缺陷密度。此外，CsPbBr ₃ QD上的配体增加了薄膜的疏水性。结果，在高温下制备的经量子点处理的CsPbl ₃太阳能电池获得了超过16%且具有高稳定性的PCE。