Hydrogen Bond Interaction Promotes Flash Energy Transport at MXene-Solvent Interface
Jiebo Li, Zhen Chi, Ruzhan Qin, Yan Li, Xubo Lin, Mingjun Hu, Guangcun Shan, Hailong Chen, Yuxiang Weng
Abstract
There are emerging applications for photothermal conversion utilizing MXene, but the mechanism under these applications related interfacial energy migration from MXene to the attached surface layer is still unknown. Here, the femtosecond pump–probe spectroscopy is employed to elucidate the ultrafast electronic energy dissipation pathways of MXene (Ti3C2Tx) under plasmonic excitation. The experimental results suggest that in water, nearly 80% energy in MXene gained from the photoexcitation quickly dissipates into surrounding water molecules within 7 ps as a hydrogen bond mediated fast channel, and the remaining energy vanishes with time constant ∼100 ps as a lattice motion mediated slow channel. This flash energy migration results in a prominent interfacial thermal conductance ∼162 MW·m–2·K–1 for the MXene–water interface. Tuning the solvent into ethanol could not only narrow the hydrogen bond mediated energy dissipation channel to 24% but also slow down the lattice motion mediated energy transport rate. Molecular dynamics simulation results further confirm that different solvents have significantly different hydrogen bond forming abilities on MXene surfaces. Our results suggest that the interfacial interaction is crucial for effective hydrogen bond formation on MXene surface to channel the excitation dissipation, providing important insights into the photothermal applications with MXene.