Photoelectrochemical study of hydrothermally grown vertically aligned rutile TiO2 nanorods

Vertically oriented TiO2 nanorods (NRs) were grown on FTO coated glass substrate using a hydrothermal process without any seed layer. The morphology and crystallinity of the nanorods were analyzed using SEM, TEM, XRD and Raman spectroscopy. The growth mechanism of the TiO2 nanorods has been discussed. The chemical bonds were studied using XPS study. The PEC properties of the TiO2 NRs were investigated in detail. TiO2 NRs photoanode demonstrated photosensing behaviour with an ON/OFF ratio of ∼96.2 and photoconversion efficiency of ∼0.72%. The incident-photon-to-current conversion efficiency (IPCE) at an incident wavelength of 360 nm was ∼31.6%. The carrier decay life time was estimated from the photovoltage decay profile. The carrier concentration, flat band voltage, Debye length and depletion width at the TiO2 NRs/electrolyte interface were estimated from the Mott-Schottky (M−S) plot. The charge transport mechanism at the semiconductor/electrolyte interface was explored from the electrochemical impedance measurements.