Dielectric and optical properties of graphitic carbon nitride-titanium dioxide nanocomposite with enhanced charge seperation

Graphitic carbon nitride (g-C3N4) a polymeric semiconductor material is appealing research topic because of enhanced absorption capability in visible region. g-C3N4-TiO2 composite material was prepared with varying composition (g-C3N4: TiO2) in the range of 0.25:1-2:1 and studied using various characterization techniques including X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) and FTIR spectroscopy for structural and morphological analysis. Optical properties were studied using UV-Vis, and photoluminescence (PL) spectroscopic techniques and dielectric properties were studied using impedance analyser. UV-visible spectra show a shift toward the higher wavelength region in composite owing to the decrease in the band gap value of g-C3N4-TiO2 composites. The dielectric constant was found increased with increasing content of g-C3N4 till the composition of 1.5:1 and decreased for higher content. The optimum composition based on above studies was found to be 1:1 and 1.5:1 with optical absorption in the range of 280-420 nm covering UV and small portion of visible light, and recombination of photogenerated charge carriers were also reduced compared to g-C3N4.