Abstract: Nanoporous TiO₂ thick films for the photoanode of Dye-sensitized Solar Cell (DSC) were prepared by integrating the “chemical dispersion method of nanoparticles” with the “doctor blade” technique. The problems concerning the preparation and storage of TiO₂ slurry in the conventional method were solved, and the better control over the microstructure of TiO₂ thick film was achieved. The crystalline structure, and morphology of the obtained film were characterized by X-ray diffraction, scanning electron microscope, and transmission electron microscope. The effects of coating time, annealing temperature, and sensitization of merbromin on the optical transmittance of TiO₂ films were examined. The prototype DSC devices were fabricated by using merbromin-sensitized TiO₂ nanoporous film as the photoanode. Results show that the novel chemical dispersion technique adopting diluted nitric acid as the dispersant and the low-polymerization PEG as the microstructure-modifier can be used to prepare TiO₂ nanoporous thick film applied in DSC. The obtained film is dense and uniform without pores, defects or delamination, and exhibits typical nanoporous feature. The coating time of slurry, the annealing temperature, and the adsorption of merbromin have significant influence on the optical transmittance of nanoporous film. The prototype DSC device sensitized by merbromin exhibits strong photovoltaic response, and the cells prepared with the photoanode by 12--15 coatings & 500℃ anneal show better performance (V_oc～430mV, I_sc～150--215μA).

Key words: TiO₂, nanoporous, thick film, merbromin, dye-sensitized solar cell