Hierarchical MoS2/CuS photonic nanostructure accelerating photothermoelectric conversion of bacterial cellulose based phase change materials

Phase change materials (PCMs)-integrated solar-thermal-electric generators (STEGs) have emerged as a promising platform for sustainable solar energy harvesting, yet faces critical challenges including liquid phase instability, insufficient photothermal efficiency, and limited thermoelectric output. Herein, we engineered hierarchical photonic confinement through the assembly of plasmonic CuS nanoparticles, broadband-absorbing MoS 2 nanosheets, and porous bacterial cellulose (BC). In this tripartite architecture, BC matrix provides robust structural integrity and enhances heat transfer via its 3D interconnected nanoporous structure; MoS 2 nanosheets enable extended photon harvesting across the ultraviolet to near-infrared spectrum; CuS nanoparticles amplify near-field optical effects through localized surface plasmon resonance. The optimized composite PCMs achieve a remarkable photothermal conversion efficiency of 93.6 % under 100 mW/cm 2 , along with excellent latent heat retention close to 100 % after 10-day thermal cycles, attributed to the plasmon-phonon coupling between MoS 2 nanosheets and CuS nanoparticles. When integrated with thermoelectric devices, this STEG delivers a high and durable thermoelectric output of 157.0 mV and 44.0 mA under 100 m W/cm 2 irradiation, enabled by the photothermal-thermoelectric coupling effects. This innovative hierarchical photonic confinement design provides a universal platform for next-generation thermal management systems and self-powered photothermal technologies.