Molecular Dipole Embedding Strategy Empower Antimony Sulfide Indoor Photovoltaics With Efficiency Over 21%

ABSTRACT Indoor photovoltaic (IPV) system harnesses ambient light energy to generate electricity, enabling the sustainable and carbon‐neutral powering of the exponentially expanding ecosystem of Internet of Things (IoT) sensors. Antimony sulfide (Sb 2 S 3 ) has emerged as a promising light harvester for next‐generation IPVs. However, its performance is severely constrained by deep‐level defect‐induced traps at Sb 2 S 3 /charge transport layer interfaces, which largely hamper the charge extraction and spark the nonradiative recombination. Here, we demonstrate a molecular dipole embedding strategy to optimize interfacial structural and electronic landscapes in Sb 2 S 3 photovoltaics. The theoretical and experimental results decipher that the rational construction of molecular dipoles can precisely tailor the interface electric field, heterojunction polarity, and chemical affinity behavior, thereby enabling the pronounced defect healing, optimized energetic arrangement, and reinforced charge extraction. Consequently, a milestone efficiency of 21.13% under LED illumination (1000 lux) is attained, which hits the record high for Sb 2 S 3 ‐based IPVs reported to date.