Li Xinyue, Xu Zhaowei, Zhao Rongmei, Ge Shifeng, Liu Tingfeng, Cai Bing, Li Mingliang, Zhang Wen-Hua
Southwest United Graduate School, Yunnan Key Laboratory for Micro/Nano Materials &Technology, National Center for International Research on Photoelectric and Energy Materials, School of Materials and Energy, Yunnan University, Kunming, 650504, China.
Adv Mater. 2025 Aug;37(34):e2508352. doi: 10.1002/adma.202508352. Epub 2025 Jun 11.
Interface engineering in inverted perovskite solar cells (PSCs) faces critical challenges arising from nonideal interfacial contact, defect accumulation, impeded carrier transport, and energy-level misalignment between the perovskite and electron transport layer, for example, phenyl-C61-butyric acid methyl ester (PCBM). These interfacial deficiencies collectively induce nonradiative recombination and degrade device stability. Herein, a multifunctional interfacial molecular bridging strategy using (benzhydrylthio)acetic acid (DSA) addresses the upper interfacial issues of inverted PSCs, achieving three synergistic roles. 1) Interfacial stabilization. A stable molecular-bridging layer is constructed with DSA at the perovskite/PCBM interface through carboxylate-Pb⁺ coordination bonds, along with π-π stacking interactions between DSA and PCBM. 2) Defect passivation. Multiple active sites in DSA molecules, such as thioether and carboxylic acid groups, can synchronously achieve chemical passivation with undercoordinated Pb sites. 3) Energy band alignment: DSA induces n-type band bending through electron donation by the thioether, reducing the work function and enhancing the electron-extraction kinetics. As a result, DSA-treated devices achieve a champion power conversion efficiency of 26.08% along with an open-circuit voltage loss of only 53 mV. Finally, the DSA-treated devices demonstrate remarkable operational stability, retaining 96% of the initial efficiency after being tracked at the maximum power point for 2000 h.
倒置钙钛矿太阳能电池（PSCs）中的界面工程面临着诸多严峻挑战，这些挑战源于不理想的界面接触、缺陷积累、载流子传输受阻以及钙钛矿与电子传输层（如苯基-C61-丁酸甲酯，PCBM）之间的能级失配。这些界面缺陷共同导致非辐射复合，并降低器件稳定性。在此，一种使用（二苯甲基硫代）乙酸（DSA）的多功能界面分子桥接策略解决了倒置PSCs的上层界面问题，实现了三种协同作用。1）界面稳定化。通过羧酸盐-Pb⁺配位键以及DSA与PCBM之间的π-π堆积相互作用，在钙钛矿/PCBM界面用DSA构建了一个稳定的分子桥接层。2）缺陷钝化。DSA分子中的多个活性位点，如硫醚和羧酸基团，可以与配位不足的Pb位点同步实现化学钝化。3）能带排列：DSA通过硫醚的电子供体作用诱导n型能带弯曲，降低功函数并增强电子提取动力学。结果，经DSA处理的器件实现了26.08%的最佳功率转换效率，开路电压损失仅为53 mV。最后，经DSA处理的器件表现出卓越的运行稳定性，在最大功率点跟踪2000小时后仍保留初始效率的96%。
