MXene与溶剂界面电子振动耦合现象的直接观测

作为一种新型的二维材料，MXene凭借其各种优异的物理化学性质已受到极为广泛的关注，例如其具有极其出色的光热转换效率. 然而，人们对MXene的光热转换机制仍然知之甚少. 本文通过结合飞秒可见和中红外瞬态吸收光谱技术，对分散在各种溶剂中MXene(Ti₃C₂T_x)纳米片内的电子能量耗散动力学进行了系统的研究. 结果表明，MXene的激发态寿命在很大程度上取决于周围的溶剂环境. 在MXene被超快激光泵浦后，可以直接观察到MXene纳米片与相邻溶剂分子之间的界面电子振动耦合现象. 这些结果表明界面相互作用在MXene的超快能量传输动力学中起着关键的作用. 这一发现可为二维体系光转换性能的改进提供了一条潜在可行的途径.

Direct Observation of Electron-Vibration Coupling at MXene-Solvent Interface

MXenes, a new family of two-dimensional (2D) materials, have received extensive in-terest due to their fascinating physicochemical properties, such as outstanding light-to-heat conversion e ciency. However, the photothermal conversion mechanism of MXenes is still poorly understood. Here, by using femtosecond visible and mid-infrared transient absorption spectroscopy, the electronic energy dissipation dynamics of MXene (Ti₃C₂T_x) nanosheets dispersed in various solvents are carefully studied. Our results indicate that the lifetime of photoexcited MXene is strongly dependent on the surrounding environment. Especially, the interfacial electron-vibration coupling between the MXene nanosheets and the adjacent solvent molecules is directly observed following the ultrafast photoexcitation of MXene. It suggests that the interfacial interactions at the MXene-solvent interface play a critical role in the ultrafast energy transport dynamics of MXene, which offers a potentially feasible route for tailoring the light conversion properties of 2D systems.