Inductive effects in molecular contacts enable wide-bandgap perovskite cells for efficient perovskite/TOPCon tandems
Yixin Luo, Yuan Tian, Ke‐Qing Zhao, Weiping Mao, Chen Liu, Jiahui Shen, Zhendong Cheng, Caner Değer, Xiaohe Miao, Zhongwei Zhang, Xuechun Sun, Libing Yao, Xu Zhang, Pengju Shi, Donger Jin, J.C. Deng, Mengyuan Tian, İlhan Yavuz, Na Dong, Ruzhang Liu, Rui Wang, Deren Yang, Jingjing Xue
Abstract
Organic molecules that serve as hole-selective contacts, known as self-assembled monolayers (SAMs), play a pivotal role in ensuring high-performance perovskite photovoltaics. Optimal energy alignment between the SAM and the perovskite is essential for desired photovoltaic performance. However, many SAMs are studied in optimal-bandgap perovskites, with limited energy level modification specifically catering to wide-bandgap perovskites. Herein, we demonstrate that the energy level of SAMs can be systematically tuned in a stepwise manner via inductive effects in the conjugated moieties, enabling rational design tailored for specific perovskite bandgaps. The resulting WBG perovskite device based on our tuned SAM achieved a power conversion efficiency (PCE) of 22.8%. Integration with crystalline silicon TOPCon subcells further enabled the construction of a perovskite/TOPCon tandem device with a PCE of 31.1% (certified 30.9%). Self-assembled monolayers targeting wide-bandgap perovskite solar cells are essential to reduce the open-circuit voltage loss. Here, the authors report the stepwise tuning of interfacial energy level through inductive effect, achieving perovskite/TOPCon tandem solar cells with efficiency over 31%.