Study of dye-sensitized solar cells with TiO2 nanoparticles/ nanofibers composite electrode using photovoltic and EIS measurements

Abstract

Increment of the efficiency of dye-sensitized solar cells (DSSC) by an innovative type of photoanode consisting of a composite mixture of conventional P-25 titanium dioxide (P25-TiO2) nanoparticles and electrospun TiO2 nanofibers (EL TiO2 NF) with optimized weight ratio is obtained. This novel composite photoanode harvests sunlight more strongly compared to a DSSC made with conventional photoanode which consists only P25-TiO2. Thus the efficiency of DSSCs made with this novel composite photoanode is significantly higher than the DSSC made with conventional P25-TiO2 photo anode. The TiO2 nanofibers were prepared by the electrospinning technique and the composite photoanode was prepared by using and weight ratios of TiO2 nanofibers in the TiO2 nanofiber: nanoparticle mixture. These cells were characterized by UV-Vis spectroscopy, J-V characteristics, EIS analysis and dark I-V measurements. While the overall efficiency of the DSSC comprising with novel photoanode with nanofibres showed 7.01% under the illumination of 1000 W m-2, the DSSCs with conventional P-25-TiO2 photoanodes showed 5.11% under the same conditions. Therefore , 37.18% enhancement in the overall efficiency is achieved by employing this novel photoanode in the DSSCs. The high efficiency of the solar cell appears to be due to the increased short-circuit photocurrent density by enhanced light harvesting caused by the increased light absorption due to scattering within the composite TiO2 Nano-structure with nanofibres. Keywords : Dye-sensitized solar cells, performance, nanoparticles, nanofibers, electrospinning, UV-VIS spectroscopy, photocurrent, light harvesting, electrolyte.