2D Ta4AlC3 and Ta4C3 nanosheets with excellent ultraviolet optical limiting behavior for laser protection

Abstract

MXenes, a novel two-dimensional (2D) layered material, have been widely studied owing to their unique electronic, chemical and optical properties. However, reports on the nonlinear absorption (NLA) properties of Ta₄C₃ have been rarely found throughout the research on MXenes, especially the optical limiting (OL) effect, which greatly limits its further development in the field of photonics and nonlinear optics. Herein, multilayer Ta₄C₃ MXenes were successfully prepared by etching Ta₄AlC₃ MAX with hydrofluoric acid (HF), and 2D Ta₄AlC₃ and Ta₄C₃ nanosheets were prepared via the ultrasonic-assisted liquid-phase exfoliation (LPE) method. To the best of our knowledge, their broadband NLA properties from the ultraviolet (UV) to infrared (IR) region under picosecond pulsed laser excitation have been systematically studied for the first time using open aperture (OA) Z-scan technique. The results show that Ta₄AlC₃ and Ta₄C₃ exhibit excellent NLA properties in the UV region, especially the very strong OL effects, indicating that they are incomparable candidates for OL materials. Our study reveals the great potential of Ta₄AlC₃ and Ta₄C₃ for laser protection, which benefits their further development in the field of photonics and nonlinear optics.