Fullerene-based electron-transporting layers (ETLs) significantly influence the defect passivation and device performance of inverted perovskite solar cells (PSCs). However, the π-cage structures of fullerenes lead to a strong tendency to self-aggregate, which affects the long-term stability of the corresponding PSCs. Experimental results revealed that [6,6]-phenyl-C₆₁-butyric acid methyl ester (PCBM)-based ETLs exhibit a certain degree of self-aggregation that affects the stability of the device, particularly under continuous irradiation stress. To modulate the aggregation behavior, we replaced a methyl hydrogen of PCBM with a phenyl group to yield [6,6]-phenyl-C₆₁-butyric acid benzyl ester (PCBB). As verified through X-ray crystallography, this minor structural modification results in more non-covalent intermolecular interactions, which effectively enhanced the electron-transporting ability of the PCBB-based ETL and led to an efficiency approaching 20%. Notably, the enhanced intermolecular forces of PCBB suppressed its self-aggregation, and the corresponding device showed significantly improved stability, retaining approximately 90% of its initial efficiency after 600 h under one-sun irradiation with maximum power point tracking. These findings provide a viable approach for the design of new fullerene derivatives to tune their intermolecular interactions to suppress self-aggregation within the ETL for high-performance PSCs.

基于富勒烯的电子传输层 (ETL) 显着影响倒置钙钛矿太阳能电池 (PSC) 的缺陷钝化和器件性能。然而，富勒烯的π笼结构导致强烈的自聚集倾向，从而影响相应PSCs的长期稳定性。实验结果表明，基于 [6,6]-苯基-C ₆₁ -丁酸甲酯 (PCBM) 的 ETL 表现出一定程度的自聚集，这会影响器件的稳定性，尤其是在连续辐照应力下。为了调节聚集行为，我们用苯基取代 PCBM 的甲基氢，得到 [6,6]-苯基-C ₆₁-丁酸苄酯 (PCBB)。通过 X 射线晶体学验证，这种微小的结构修饰导致了更多的非共价分子间相互作用，有效地增强了基于 PCBB 的 ETL 的电子传输能力，使效率接近 20%。值得注意的是，增强的 PCBB 分子间力抑制了其自聚集，相应的器件显示出显着提高的稳定性，在最大功率点跟踪的单日光照射下 600 小时后保持其初始效率的约 90%。这些发现为设计新的富勒烯衍生物提供了一种可行的方法，以调整它们的分子间相互作用，从而抑制高性能 PSC 在 ETL 内的自聚集。