Effect of Ti3C2Tx MXene content on the structural properties and optical band gap of PVA/PEG nanocomposite thin films

In this work, Ti 3 C 2 T x MXene was synthesized by selective chemical etching of the Ti 3 AlC 2 MAX phase and incorporated into a poly (vinyl alcohol) (PVA)/poly (ethylene glycol) (PEG) matrix to fabricate nanocomposite thin films with Ti 3 C 2 T x MXene loadings of 0.5–1.5 wt% by using a simple drop-casting technique. The structural, morphological, compositional, and optical characteristics of pure PVA/PEG and Ti 3 C 2 T x MXene/PVA/PEG nanocomposite thin films were systematically investigated using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and UV–Vis spectroscopy. Fourier transform infrared (FTIR) analysis revealed enhanced interfacial interactions between the polymer chains and the surface functional groups of Ti 3 C 2 T x MXenes. XRD and field-emission scanning electron microscopy (FESEM) results confirmed the successful formation of MXene and its incorporation into the polymer matrix. The crystallinity index showed a non-monotonic trend with Ti 3 C 2 T x MXene loading, reaching a maximum at 0.5 wt% Ti 3 C 2 T x MXene with crystallinity indices of 48.01% and 49.87% as determined by XRD and FTIR, respectively, due to the heterogeneous nucleation effect of MXene nanosheets at low filler loading. UV–Vis spectroscopy showed a gradual red shift of the absorption edge as the Ti 3 C 2 T x MXene concentration increased. Both the direct and indirect optical band gap energies decreased from 5.49 to 4.98 eV and from 5.17 to 3.28 eV, respectively, as the Ti 3 C 2 T x MXene content increased from 0.0 to 1.5 wt%. These findings suggest that Ti 3 C 2 T x MXene/PVA/PEG nanocomposite thin films are promising candidates for future investigation in optoelectronic, sensing, and energy-related applications.