Development of dye sensitized TiO2 thin films for efficient energy harvesting

Abstract

In the present investigation, we are reporting development of 3D nanoflower like architecture of TiO2 for dye sensitized solar cell (DSSC). Initially, TiO2 thin films were synthesized by using a simple hydrothermal approach. The effect of deposition time on the optostructural, morphological, compositional and photoelectrochemical properties of TiO2 thin films was studied. The optical study reveals direct and allowed transition with band gap variation in the range of 2.4–3.0 eV. The XRD pattern confirms rutile tetragonal crystal structure with crystallite size ranging from 20 to 50 nm. The morphological analysis shows presence of 1D nanorods assembling to give a 3D nanoflower like architecture. The compositional data confirms the presence of titanium and oxygen in the 1:2 with respective oxidation state. HRTEM images are in good agreement with SEM images confirming single crystalline nature of TiO2 thin films. As deposited TiO2 thin films are sensitized with different concentrations of Betanin dye. This natural dye sensitized TiO2 is used as photoelectrode to determine the photovoltaic performance. The purity and structure of betanin dye was determined by LC-MS and FT-IR. The PEC performance increases from 5.82% to 14.21% with increase in deposition time. Further in order to study the charge transport mechanism EIS is done. The stability study of T-9 sample is done to confirm the stability.