Improved charge extraction in inverted perovskite solar cells with dual-site-binding ligands

• Published in: Science (American Association for the Advancement of Science) Vol. 384; no. 6692; pp. 189 - 193
• Main Authors: Chen, Hao, Liu, Cheng, Xu, Jian, Maxwell, Aidan, Zhou, Wei, Yang, Yi, Zhou, Qilin, Bati, Abdulaziz S. R., Wan, Haoyue, Wang, Zaiwei, Zeng, Lewei, Wang, Junke, Serles, Peter, Liu, Yuan, Teale, Sam, Liu, Yanjiang, Saidaminov, Makhsud I., Li, Muzhi, Rolston, Nicholas, Hoogland, Sjoerd, Filleter, Tobin, Kanatzidis, Mercouri G., Chen, Bin, Ning, Zhijun, Sargent, Edward H.
• Format: Journal Article
• Language: English
• Published: United States The American Association for the Advancement of Science 12.04.2024; AAAS
• Subjects: Energy conversion efficiency; Fullerenes; Ligands; Perovskites; Photovoltaic cells; Science & Technology - Other Topics; Solar cells
• ISSN: 0036-8075; 1095-9203; 1095-9203
• DOI: 10.1126/science.adm9474

Inverted (pin) perovskite solar cells (PSCs) afford improved operating stability in comparison to their nip counterparts but have lagged in power conversion efficiency (PCE). The energetic losses responsible for this PCE deficit in pin PSCs occur primarily at the interfaces between the perovskite and the charge-transport layers. Additive and surface treatments that use passivating ligands usually bind to a single active binding site: This dense packing of electrically resistive passivants perpendicular to the surface may limit the fill factor in pin PSCs. We identified ligands that bind two neighboring lead(II) ion (Pb 2+ ) defect sites in a planar ligand orientation on the perovskite. We fabricated pin PSCs and report a certified quasi–steady state PCE of 26.15 and 24.74% for 0.05– and 1.04–square centimeter illuminated areas, respectively. The devices retain 95% of their initial PCE after 1200 hours of continuous 1 sun maximum power point operation at 65°C. Ligands that protect perovskite layers from degradation can also increase solar cell resistance. Chen et al . minimized this problem by forcing the ligands to lie flat on the surface. A design study identified 4-chlorobenzenesulfonate as a ligand that would bind two neighboring lead(II) ion defect sites in a planar orientation and also minimize the energy mismatch with the fullerene electron-transfer layer. An inverted solar cell with a 1-square-centimeter illuminated area had a power conversion efficiency of 24.7%, and 95% of that efficiency was maintained for 1200 hours of continuous operation at 65°C. —Phil Szuromi