Interfacial Defect Engineering for Enhanced Polymer Solar Cell Performance

ABSTRACT Plasmonic metal nanoparticles provide a promising strategy to simultaneously modulate optical absorption and charge transport in polymer solar cells. Here, we present a computational investigation of PTB7:PC70BM organic solar cells incorporating metal nanoparticles as active regulators of interfacial energetics and recombination dynamics. Localized surface plasmon resonance (LSPR) is shown to influence device performance not only through enhanced photocarrier generation but also via plasmon‐induced modification of band alignment and defect states. By systematically tuning hole‐acceptor concentration, defect density, and parasitic resistances, we identify the PEDOT:PSS/PTB7:PC70BM interface as a critical control point for plasmon‐mediated charge extraction. Optimized valence band alignment and interfacial defect regulation yield a power conversion efficiency of 8.06%, in close agreement with experiment. These findings establish plasmonic nanostructures as multifunctional tools for coupled optical and electronic optimization in organic photovoltaics.