Tuning Thermal Transport Through Atomically Thin Ti 3 C 2 T z MXene by Current Annealing in Vacuum

Abstract

Heat transport across vertical interfaces of heterogeneous 2D materials is usually governed by the weak Van der Waals interactions of the surface-terminating atoms. Such interactions play a significant role in thermal transport across transition metal carbide and nitride (MXene) atomic layers due to their hydrophilic nature and variations in surface terminations. Here, the metallicity of atomically thin Ti 3 C 2 T z MXene, which is also verified by scanning tunneling spectroscopy for the first time, is exploited to develop a self-heating/self-sensing platform to carry out direct-current annealing experiments in high (<10 −8 bar) vacuum, while simultaneously evaluating the interfacial heat transport across a Ti 3 C 2 T z /SiO 2 interface. At room temperature, the thermal boundary conductance (TBC) of this interface is found, on average, to increase from 10 to 27 MW m −2 K −1 upon current annealing up to the breakdown limit. In situ heating X-ray diffraction and X-ray photo-electron spectroscopy reveal that the TBC values are mainly affected by interlayer and interface spacing due to the removal of absorbents, while the effect of surface termination is negligible. This study provides key insights into understanding energy transport in MXene nanostructures and other 2D material systems.