Photothermal‐Mediated Carrier Dynamics in Ti ₃ C ₂ T _x MXene Revealed by Time‐Resolved Terahertz Spectroscopy

ABSTRACT 2D Ti ₃ C ₂ T _x MXene film exhibits exceptional electrical and thermal properties, yet the interplay between lattice thermal dissipation and carrier dynamics under photo‐excitation remains unresolved. Using time‐resolved terahertz spectroscopy, we systematically investigated photothermal‐mediated carrier relaxation mechanisms in Ti ₃ C ₂ T _x MXene film by precisely varying layers. The slowest relaxation time exhibits a linear dependence on film thickness, mirroring lattice cooling dynamics governed by thermal boundary conductance (TBC). And by engineering interfacial TBC through substrate selection, effective modulation of transient carrier relaxation dynamics was furthermore demonstrated. These findings confirm the universal photothermal mediated carrier relaxation in Ti ₃ C ₂ T _x MXene film due to strong carrier‐phonon coupling. Our insights establish interface engineering as a viable strategy to control the carrier relaxation process in Ti ₃ C ₂ T _x MXene, advancing their design for optoelectronic and energy conversion applications. This work bridges the critical gap between lattice thermal dissipation and carrier kinetics in MXene, offering new insights into heat‐managed quantum material platforms.