Suppressing Nonradiative Recombination at the Buried Interface for Highly Efficient n‐i‐p Perovskite Solar Cells with a Multifunctional Dipolar Molecular Bridge
Can Meng, Xinbao Lin, Ran Zhou, Xu Zhao, Zixuan Li, Yanan Liu, Tianci An, Min Li, Zejing Li, Linfeng Cui, Bo Liu
Abstract
Abstract The nonradiative recombination losses at the buried interface, arising from interfacial defects, unfavorable energy level alignment, and residual strain, are the main impediment for perovskite solar cells (PSCs) to achieve superior efficiency and stability. To address this issue, a multifunctional dipolar molecular bridge, 1,4‐phenylenebis(1‐cyanoethene‐2,1‐diyl) bisphosphonic acid (CS‐103), is constructed by symmetric dual anchoring strategy, which can simultaneously interact with both sides at the buried interface of n‐i‐p PSCs. The surface defects of SnO 2 and perovskite are synchronously passivated, while the interfacial energy level alignment is also well optimized due to the high surface potential and large regional dipole moment of CS‐103. Meanwhile, the perovskite crystallization process can also be optimized, thus resulting in relatively high crystallinity, few surface defects, large grain size, and smooth surface. Furthermore, with CS‐103 as the chemically bonded molecular bridge, the residual strain at the buried interface is effectively released. Accordingly, the nonradiative recombination losses at the buried interface are suppressed to the greatest extent, thus resulting in a champion power conversion efficiency (PCE) of 24.77%. The unencapsulated PSCs maintain 91% of initial PCE for more than 1000 h according to ISOS‐D‐1 protocol, presenting notable long‐term stability.