Photothermal effects control ultrafast charge transport in titanium carbide MXenes
- Wenhao Zheng
- Hugh Ramsden
- Stefano Ippolito
- Max van Hemert
- Danzhen Zhang
- Teng Zhang
- Dongqi Li
- Guanzhao Wen
- Jaco J. Geuchies
- Minghao Yu
- Xinliang Feng
- Yury Gogotsi
- Klaas-Jan Tielrooij
- Hai I. Wang
2026-01-29
Titanium carbide MXene (Ti₃C₂T ₓ ) is an emerging metallic material with promise for (opto)electronics and thermal management. Yet how photoexcitation—particularly via photogenerated thermal energy—modifies its charge carrier dynamics remains poorly understood. By combining time-resolved terahertz spectroscopy and transient reflectance measurements, we reveal a long-lived, photo-induced suppression of conductivity, which we attribute to efficient lattice heating and slow heat dissipation in Ti₃C₂T x . A systematic variation of pump photon energy reveals that this ‘negative’ photoconductivity can equivalently be induced by lattice temperature increases, indicating a thermal origin. Repetition-rate-dependent transient reflectance measurements further show residual heat persisting over 100 ns, substantially longer than in conventional metals. Our work presents a unified understanding of photothermal effects in Ti₃C₂T ₓ and their influence on non-equilibrium charge transport, underscoring its potential for photothermal electronics and light-to-thermal energy storage applications.