Effect of Au nanoparticles in persistent photoconductivity and dielectric relaxations of anatase TiO2

In this research, the TiO2 samples decorated with and without Au NPs were synthesized by the simplest sol-vothermal method. The structural and morphological analysis of the samples were examined by XRD and TEM. Moreover, the dielectric properties highlight the frequency and temperature dependence of dielectric parameters using impedance spectroscopy. The obtained results present a critical dielectric constant of TiO2 decorated with and without Au NPs about 1800, and 3000, respectively, at room temperature. Moreover, the frequency dependent plot of modulus displays a non-Debye relaxation type. Furthermore, I-V characteristics indicate the existence of a persistent photoconductivity (PPC) at room temperature for the Au@TiO2 device. The origin of PPC is credited to the electrons trapped/de-trapped by interface states. The fabricated devices show high sensitivity to 375 nm UV illumination at 7.6 mW. These important dielectric and optoelectronics properties of the as-prepared samples make them fascinating materials for use in UV photodetector.