Split‐Standing Molecular Engineering for Textured Silicon/Perovskite Tandems
Xiaonan Wang, Yuan Tian, Libing Yao, Shaochen Zhang, Qingqing Liu, Ke Zhao, Jiazhe Xu, Jingjing Zhou, Caner Değer, İlhan Yavuz, Jingjing Xue, Rui Wang
Abstract
Abstract To effectively minimize reflection losses and achieve compatibility with industrial‐scale silicon production lines, textured silicon/perovskite tandem solar cells have garnered significant attention in recent research. However, achieving uniform and stable coverage of the textured silicon substrate with hole‐selective layer (HSL) remains a significant challenge. Herein, a HSL material, DPAICz ((indolo[2,3‐a]carbazole‐11,12‐diylbis(ethane‐2,1‐diyl))bis(phosphonic acid)), is reported specifically designed for textured silicon substrate. Compared to the typical HSL material 2PACz, DPAICz features a π‐expanded conjugated core and multiple anchoring groups, forming a split‐standing configuration with anchoring groups positioned on opposite sides, resulting in superior anchoring stability on textured substrate under external stimuli. Moreover, DPAICz exhibited a larger molecular dipole moment and a more pronounced p‐type characteristic, enhancing the interfacial hole extraction efficiency. Consequently, wide‐bandgap (1.68 eV) perovskite solar cells employing DPAICz as the HSL achieved a champion power conversion efficiency (PCE) of 23.42%. Introducing the DPAICz into monolithic silicon/perovskite tandem solar cells greatly improved their performance, achieving a remarkable PCE of 32.55% in 1 cm 2 area. Importantly, the unencapsulated tandems based on DPAICz exhibited significantly enhanced long‐term operational stability, retaining 96% of its initial PCE after 880 h of continuous 1‐sun light soaking at 45 °C under open‐circuit condition.