Switchable optical nonlinear properties of monolayer V2CTX MXene

The study of the non-linear optical phenomena describing light-matter interactions in two-dimensional (2D) crystalline materials has promoted the widespread application of photonics. In this work, 2D MXene (V2CTx) monolayer nanosheet were synthesized by selective etching of Al from V2AlC at room temperature. The nanosecond Z-scan technique with a broadband of 450–700 nm was used to investigate the non-linear optical properties of V2CTx nanosheets. The z-scan measurements showed that V2CTx nanosheets exhibit saturable absorption most of the time, which was due to the bleaching of the ground state plasma. Especially at 500 nm, the transition from saturated absorption to reverse saturable absorption occurred. The experimental results demonstrate that V2CTx has optical nonlinear properties. The magnitude of the nonlinear absorption of V2CTx is wavelength dependent, and the reverse saturable absorption is due to two-photon absorption. This also indicates that V2CTx nanosheets have great potential for future ultrathin optoelectronic devices.