Microstructure, electrical and humidity sensing properties of TiO2/polyaniline nanocomposite films prepared by sol–gel spin coating technique

Abstract

High sensitive resistive type humidity sensor based titanium oxide/polyaniline (TiO2/PANI) nanocomposite thin films prepared by a sol–gel spin coating technique on an alumina substrate. The resultant nanocomposites were characterized by using X-ray diffraction (XRD), Field emission electron microscopy, Fourier transform infrared spectroscopy (FTIR), UV–Vis absorbance and energy dispersive spectra analysis. In the XRD patterns of both pure and TiO2/PANI composite confirms the deposition of PANI on TiO2 and the average size of the composite particle was found to be 32 nm. Large number of nano grain surface being covered by PANI, which agrees very well with the results obtained by XRD studies. FTIR and UV–Vis spectra reveal that the PANI component undergoes an electronic structure modification as a result of the TiO2 and PANI interaction. The room temperature resistivity was found to be for TiO2 and TiO2/PANI nanocomposite films 1.42 × 106 and 2.56 × 103 Ω cm respectively. The obtained TiO2/PANI nanocomposites sensor exhibited higher humidity sensing performance such as high sensitivity, fast response (20 s) and recovery time (15 s) and high stability.