Improvement physical and photoelectrochemical properties of TiO2 nanorods toward biosensor and optoelectronic applications

Abstract

In this study we examine effect of the solvent ratio on TiO2 physical and photoelectrochemical properties utilizing economical hydrothermal process. Sample properties were examined using XRD, SEM, Raman, UV–vis, PL, photocurrent, Mott–Schottky, and EIS measurements. XRD patterns revealed that TiO2 samples represent a polycrystalline nature with a Tetragonal structure. Peaks at 609, 144, and 443 cm−1 were observed in Raman spectra indicating the production of the TiO2 rutile phase. SEM images showed that TiO2 nanorods formed evenly with square top facets and a tetragonal form. UV–vis results displayed an optical absorption edge between 386 and 405 nm which is associated with the band gap of TiO2 NRs films. The generated TiO2 NRs films exhibit n-type semiconductor behavior according to the photocurrent measurements. Mott-Schottky experiments indicated that the donor density and flat band potential varied with decreased acid ratio from 1.55 × 1018 to 3.33 × 1018 cm−3 and-0.47 to-0.72 V, respectively. As observed by EIS, the resistivity to charge transfer declined, reaching its lowest level at 5:11 ml, indicating improvement of electrochemical activity and structural properties with decreasing the HCl concentration. Additionally, the fabricated TiO2 NRs films was employed as biosensor for glucose where a fast amperometric response and good operating stability were detected.