Hierarchically Enhanced Plasmonic Absorber with Abundant Nanomirrors for Effective Photoelectrochemical Performance

The synergistic combination of plasmonic metals and semiconductors demonstrates marvelous potential for nanocomposite design, particularly in enhancing photoelectrochemical performance through rich interfacial modifications and component properties adjustments. In terms of it, nanocomplexes of metal/insulator or semiconductor/metal have emerged heatedly, commonly depicted as nanomirror structures. In this work, a sandwiched nanomirror structure comprising a core Ag nanorods, a TiO 2 middle nanogap, and dual types of Au and Ag particles outermost is presented, putting forward a novel design idea of rolling the planar complex up to amplify the potential interaction systems. The TiO 2 middle layer enables the intrinsic generation of charge carriers upon light exposure, while the established heterojunctions promote their efficient separation. Additionally, both the inner Ag NRs and outer metal nanoparticles exhibit localized surface plasma resonance effects to realize enhancement of electric fields, where plasmonic coupling between them generates field hotspots within TiO 2 layer, thereby expanding light absorption range and enhancing light capture intensity. Beyond, hot electrons from plasmonic metals traverse Schottky barriers into TiO 2 to participate in further reactions, all of which contribute to heightened PEC performance of the nanostructure. In this work, the path is paved for innovative nanostructure design integrating plasmonic metals with semiconductors, offering promising implications for energy‐related applications.