Photovoltaic efficiency on dye-sensitized solar cells (DSSC) assembled using Ga-incorporated TiO2 materials

This study examined the photoelectric conversion efficiency of DSSC (dye-sensitized solar cell) when nanometer sized Ga (0.25, 0.50, and 1.00 mol%)-TiO2 prepared using a hydrothermal method was employed as a working electrode material. The particle sizes observed in the transmission electron microscopy images were < 20 nm in all samples. However, with increasing Ga concentration, the size increased and the shapes transformed to a stick form. The absorption band was slightly blue-shifted upon the incorporation of gallium ions, but the intensity of the photoluminescence (PL) curves of the Ga-incorporated TiO2 was significantly smaller, with the smallest case being the 0.50 mol% Ga-TiO2. which was related to recombination between the excited electrons and holes. When Ga-TiO2 was applied in DSSC, the energy conversion efficiency was enhanced considerably compared to that using pure TiO2: it was approximately 4.57% with the N3 dye under 100 mW/cm(2) of simulated sunlight. These results are in agreement with an electrostatic force microscopy (EFM) study showing that the electrons were transferred rapidly to the surface of Ga-TiO2 film, compared with that on a pure TiO2 film. (C) 2010 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.