2D V2C and V2AlC layers: ascendant deep ultraviolet optical limiting materials

Abstract

Two-dimensional (2D) transition metal carbides (MXenes), known for their unique properties, have ignited a surge of extensive interdisciplinary research. However, the broadband nonlinear absorption properties of MXenes have rarely been explored in prior studies, particularly in the deep ultraviolet region. Furthermore, the nonlinear optical properties of the precursor MAX phase are often overlooked. In this study, we synthesized a 2D V₂C multilayer MXene by selectively etching aluminum from V₂AlC. The broadband nonlinear optical behaviors of both V₂AlC and V₂C nanosheets were investigated using open aperture and closed aperture Z-scan techniques, spanning a wide range from the deep ultraviolet to near-infrared wavelengths. Additionally, we employed density functional theory (DFT) calculations to determine the energy band structures. The results reveal that both V₂AlC and V₂C nanosheets exhibit excellent optical limiting properties in the deep ultraviolet range, along with a significantly larger nonlinear refractive index in the visible spectrum. These findings underscore the importance of V₂AlC and V₂C nanosheets as promising materials for optical limiting applications, thereby broadening their potential applications in nonlinear optics.