Characterization and third order non-linear optical properties study of the MXene/PVA composite nanofibers

This study reports the successful synthesis and detailed characterization of MXene/PVA composite nanofibers fabricated via electrospinning, with a focus on their third-order nonlinear optical (NLO) properties. MXene nanosheets (Ti₃C₂Tₓ), derived from Ti₃AlC₂ precursors through hydrofluoric acid etching, were uniformly integrated into a polyvinyl alcohol (PVA) matrix. Structural, chemical and morphological analyses using XRD, FTIR, FE-SEM, and EDS confirmed effective exfoliation, surface functionalization, and homogeneous dispersion of MXene within the polymeric network. Nonlinear optical measurements performed via the Z-scan technique under continuous-wave 532 nm laser irradiation revealed a pronounced third-order response, characterized by a negative nonlinear refractive index (n₂ = −8.08 × 10⁻⁶ cm²/W) and a nonlinear absorption coefficient (β = −0.014 cm/W), indicative of self-defocusing behavior and dominant two-photon absorption (TPA). These optical features, combined with a high linear absorption coefficient (α = 1078 cm⁻¹), may reflect strong light–matter interaction and photothermal potential. The integration of two-dimensional MXene nanosheets within the PVA matrix enhances the optical responsiveness, and functional adaptability of the nanofibers. These results make MXene/PVA composites a promising candidate for intensity-dependent nonlinear optical applications.