Tailoring Plasmon-induced Hot Carriers in 2D Ti3C2 T x MXene via Surface Terminations

Abstract

Ti3C2Tx MXenes are emerging plasmonic materials whose tunable surface terminations provide a route for plasmon engineering. However, termination-dependent plasmonic properties of Ti3C2Tx remain largely unexplored. Using real-time time-dependent density functional theory, we investigate plasmon excitations and hot-carrier generation in Ti3C2Tx terminated by O, F, Cl, and OH. Surface terminations regulate the plasmonic response, leading to distinct energy distributions and spatial localization of hot carriers in Ti3C2Tx. In Ti3C2O2, the highly oxidized Ti drives spatial separation of hot holes and electrons, potentially suppressing their recombination. Ti3C2F2, Ti3C2Cl2, and Ti3C2(OH)2 instead show similar carrier localization, reflecting their comparable electronic structures. Notably, Ti3C2(OH)2 exhibits a larger hot-carrier population, consistent with its greater absorbed energy under the selected excitation conditions. These findings establish surface termination engineering as a strategy for controlling plasmonic hot carriers in MXenes, with implications for plasmon-driven applications.