Photothermal Conversion Property of (Au Nanocup)-(Cu₂O Nanocube) Hybrids Supported by MXene Nanosheets

Integrating multiple mechanisms to optimize electromagnetic field enhancement and charge transfer is vital for maximizing the photothermal conversion efficiency. In this study, a structurally tunable ternary plasmonic hybrid, with (Au nanocup)-(Cu2O nanocube) hybrids dispersed upon two-dimensional Ti3C2TX MXene ultrathin nanosheets, is prepared and employed for photothermal conversion application. The Au–Cu2O nanostructures are synthesized through a process involving the overgrowth of Cu2O nanocubes, with controlled size and quantity, onto the surface of the Au nanocups. Furthermore, transferring the Au–Cu2O nanostructures onto plasmonic Ti3C2TX nanosheets generates further enhanced electromagnetic field intensity around their interface. The photothermal conversion evaluation indicates that the photothermal conversion performance of the MXene/Au–Cu2O hybrids is significantly improved, achieving a photothermal conversion efficiency of 51.2% under 808 nm laser excitation, which is attributed to the magnetic plasmon resonance of the Au nanocups, the hot hole injection process due to the multisite growth of Cu2O, and the electric field enhancement at the MXene and Au–Cu2O interface. This work provides a promising approach to improve photothermal conversion efficiency through the multisite growth of Cu2O.