Enhancing the performance of dye-sensitized solar cells based on an organic dye by incorporating TiO 2 nanotube in a TiO 2 nanoparticle film

Abstract

The photoelectrochemical properties of a high molar extinction coefficient charge transfer organic dye containing thienylfluorene segment called FL, and the effect of incorporating TiO 2 nanotube (TiNT) in TiO 2 nanoparticle film along with the above dye on the photovoltaic performance of dye-sensitized solar cells (DSSCs) were investigated. The influence of soaking time of the TiO 2 electrode in dye solution and the effect of varying its concentration, on the solar cell efficiency was also studied. Cyclic voltammetric (CV) analysis revealed the linear relationship between the anodic peak current and the scan rate, indicating a surface-confined diffusion process. The surface morphology of TiNT was characterized using SEM, TEM and XRD. The open-circuit voltage ( V OC) of the DSSC increased with the increase in the wt% of TiNT and shows optimal value at about 5 wt%, which is correlated with the suppression of the electron recombination as found out from the electron lifetime studies. The electrochemical impedance spectroscopy (EIS) technique was employed to quantify the charge transport resistance ( R ct) and electron lifetime under different ratios of the TiNT/nanoparticle. The electron lifetimes of the DSSCs based on FL and N3 dye were very close to one another and the DSSC based on the FL showed respectable photovoltaic performance of ca. 7.8% under the light intensity of 100 mW cm −2 (AM 1.5G).