Photothermal Conversion Property of (Au Nanocup)-(Cu<sub>2</sub>O Nanocube) Hybrids Supported by MXene Nanosheets

Integrating\nmultiple mechanisms to optimize electromagnetic field\nenhancement and charge transfer is vital for maximizing the photothermal\nconversion efficiency. In this study, a structurally tunable ternary\nplasmonic hybrid, with (Au nanocup)-(Cu<sub>2</sub>O nanocube) hybrids\ndispersed upon two-dimensional Ti<sub>3</sub>C<sub>2</sub>T<sub>X</sub> MXene ultrathin nanosheets, is prepared and employed for photothermal\nconversion application. The Au–Cu<sub>2</sub>O nanostructures\nare synthesized through a process involving the overgrowth of Cu<sub>2</sub>O nanocubes, with controlled size and quantity, onto the surface\nof the Au nanocups. Furthermore, transferring the Au–Cu<sub>2</sub>O nanostructures onto plasmonic Ti<sub>3</sub>C<sub>2</sub>T<sub>X</sub> nanosheets generates further enhanced electromagnetic\nfield intensity around their interface. The photothermal conversion\nevaluation indicates that the photothermal conversion performance\nof the MXene/Au–Cu<sub>2</sub>O hybrids is significantly improved,\nachieving a photothermal conversion efficiency of 51.2% under 808\nnm laser excitation, which is attributed to the magnetic plasmon resonance\nof the Au nanocups, the hot hole injection process due to the multisite\ngrowth of Cu<sub>2</sub>O, and the electric field enhancement at the\nMXene and Au–Cu<sub>2</sub>O interface. This work provides\na promising approach to improve photothermal conversion efficiency\nthrough the multisite growth of Cu<sub>2</sub>O.