Structural, linear/nonlinear optical and electrical studies on PVP/CMC blend filled with hydrogen titanate nanotubes and TMAI

In this study, the optical and electrical characteristics of a PVP/CMC blend have been improved by doping with hydrogen titanate nanotubes (HTNT) and tetramethylammonium iodide (TMAI) for adaptable eco-friendly applications. Undoped and doped PVP/CMC/HTNT/x wt% TMAI blends were formed using casting procedure, x = 0.0, 0.05, 0.1, 0.15, 0.2. HRTEM micrographs of HTNT manifested a tubular structure. XRD measurements manifested a clear modification in the structure of the PVP/CMC blend owing to HTNT/TMAI doping. Diffuse reflectance and transmittance measurements revealed a big enhancement in absorption, in the range 250-400 nm, with a clear reduction in transmittance of PVP/CMC blend upon loading HTNT/TMAI, especially for x = 0.1. The direct and indirect bandgaps (4.86, 4.36 eV) for PVP/CMC were reduced attaining minimum values (2.87, 3.46) and 2.99 eV for x = 0.15 and 0.1 wt% TMAI, respectively. Also, the refractive index of the blend increased especially for the Vis/IR region (similar to 1.35) getting a maximum value (2.85) for x = 0.1. The influence of HTNT/TMAI doping on the different optical parameters: absorption coefficient, optical density, dielectric constant, optical conductivity, optical surface resistance, thermal emissivity and nonlinear optical parameters has been explored. The fluorescence intensities and CIE chromaticity coordinates of doped blends are affected by the excitation wavelength and the kind of fillers. From dielectric measurements, blends doped with 0.15 and 0.2 wt% TMAI have a higher capacitive nature than the undoped blend. Except for the blend containing 0.1 wt% TMAI, which possesses the highest energy density, all doped blends were found to have the lowest energy density compared to the undoped blend. The AC conductivity reached its highest value as the amount of TMAI doping became 0.15 wt%.