Influence of particle size on band gap and dielectric properties of TiO2 nanomaterials

Abstract

In this work TiO2 nanomaterial of different particle size were synthesized by varying the pH of the solution by hydrolysis and peptization method. These samples were characterized by XRD, UV and SEM. The XRD reveals the formation of anatase phase form of TiO2 nanoparticles having the particle size in the range 15 nm to 35 nm. The calculated band gap values by Tauc plot for the prepared samples increases with decrease in particle size. These samples are pelletized to study the dielectric properties using Impedence Analyzer Interface in the frequency range from 1 Hz to 1 M Hz. From the dielectric studies it was observed that dielectric constant, tanδ and dielectric loss were maximum in lower frequency range, as the frequency increases these dielectric parameters decreases rapidly at low frequency region and almost constant values were recorded at higher frequencies. At lower frequencies, the dielectric parameters (dielectric constant, loss, and tanδ) increases with increase of pH up to pH 8 due to space charge polarization. The value of dielectric constant recorded at pH 10 is almost same as that of pH 8, for slight decrease in the values were recorded for dielectric loss and tan δ at pH 10 due to space charge polarization with the particle size.