Using hybrid silica-conjugated TiO2 nanostructures to enhance the efficiency of dye-sensitized solar cells

In this study, hybrid silica-conjugated TiO2 photoelectrodes were developed in order to enhance the efficiency of a dye-sensitized solar cell. The relative changes in surface crystallite size and chemical surface states of TiO2 composites were investigated by XRD, XPS, and UV-vis spectroscopy. Therein, the chemical compositions of the nanostructured photoelectrode surfaces were observed to significantly change when the glass powder Si atoms became chemically bonded with the Ti atoms on the photoelectrode surface without appreciable changes to the crystalline structure of TiO2. Furthermore, a significant conversion of Si-O-x into Si-O at the surface of the photoelectrode was observed following the addition of glass powder, which confirms the covalent bonding of Si and Ti atoms into Ti-O-Si. A maximum cell efficiency (eta from 5.8% to 8.5%) was observed when 2 wt% of the low-temperature glass powder was added to the TiO2 with a constant amount of dye loading. This observed peak in solar cell efficiently is most likely due to an increase in light harvesting, which is a result of an enhancement of light scattering and the coordination between Ti and Si to establish a Ti-O-Si bond. (C) 2010 Elsevier Ltd. All rights reserved.