Preparation And Properties Of Dye-sensitized Solar Cell With A Reflective Film Photoanode

Since professor M. Gratzel introduced the nanoporous films into dye-sensitized wide band semiconductor research and made the breakthrough in the photoelectric conversion efficiency. Because of their simple structure, low-cost, simple assemble technology, high efficiency, dye-sensitized solar cells (DSSC) received wide attention from researchers. Semiconductor film, as the anode of the DSSC, is the main component section. Serveing as the role of the dye adsorption,electron transmission and the regeneration of the dye. Semiconductor oxides used in DSSC include TiO2, ZnO, SnO2, Nb2O5, In2O3, and so forth. Due to the resource abundance, nontoxicity, chemical stability, appropriate band gap, superior optical and dielectric effects, TiO2 becomes the best choice for DSSC.In this paper, we pay our attention to the improving the incident light. The transparent TiO2 film was prepared by sol-gel method, the monolayer of PS (polystyrene) spheres were applied on the film, which act as PS template in order to prepare TiO2 shell. The performances of the prepared TiO2 electrodes were studied in detail. The main work and main results are summarized as followings:(1) The PS spheres were prepared by soap-free emulsion polymerization. By choosing styrene as monomer, water as the dispersion medium and ammonium persulfate as initiator, we can obtain monodisperse and morphology uniform PS spheres. Though changing the amount of ammonium persulfate, the different distributions of the PS spheres were obtained. The diameter of PS spheres decreased with increasing the amount of the ammonium persulfate.(2) The large area self-assembled ordered monolayer of template from PS spheres was assembled on water surface. The prepared template was choosed to fabricate large area ordered TiO2 shell, we hve also investigated the prepared conditions such as the preparation of organometallic precursor solution, vertical immersion time, immersion cycle times, we have illustrated the best experiments condition of the prepared ordered shell structure. The The phase and crystallization of the products were characterized by powder X-ray diffraction (XRD), The size and morphology were observed using scanning electron microscope (SEM). The result suggested that the TiO2 shell size is basically the same with the particle size of the PS, on shrinkage phenomena were observed. XRD result showed that the heat-treated TiO2 particles wrer anatase structure.(3) The anatase nanocrystalline TiO2 film was prepared on fluorine-doped tin oxide (FTO) glass by sol-gel method. The TEM image showed that the TiO2 particles size was about 10-20 nm, When sensitized by N719 ethanol solution, Using the PROVA 200 solar cell analyzer measured the I-V curve in sunlight (AM1.5,100 mW/cm2), the nc-TiO2 film based 10-20 nm particles gave a low conversion efficiency of only 2.42%, The low efficiency is attributed to the poor incident light absorption of the transparent titanium dioxide film. The TiO2 shell synthesized by PS template, when combinated with traditional nanocrystal TiO2 film, the short circuit current and conversion efficiency both have been improved, to avoid loss of the incident light, the reason is for this particular shell structure to increase the propagation path of light in the film.