采用“粉末刮涂”与“化学分散”相结合的方法制备了用于染料敏化太阳电池光阳极的纳米多孔TiO2厚膜,解决了传统工艺中TiO2浆料难于制备和保存等问题,同时可对膜层微结构进行精确调控.采用X射线衍射、扫描电镜、透射电镜等表征所得膜层的晶体结构、表面和断面形貌;采用透过光谱考察了涂覆次数、退火温度、汞溴红敏化对TiO2膜光学性质的影响,并以汞溴红敏化TiO2膜为光阳极制作了染料敏化太阳电池原型器件.结果表明,采用以稀硝酸为分散剂、低分子量聚乙二醇为结构调控剂的化学分散技术可以制得满足染料电池要求的TiO2厚膜.所得膜层致密均匀,无孔洞、缺陷以及分层现象,在纳米尺度表现出典型的纳米多孔结构特征.浆料涂覆次数、退火温度、汞溴红吸附对纳米多孔膜层的光学透过率影响显著.采用汞溴红敏化TiO2光阳极制作的染料电池原型器件具有较强的光电响应,经12-15次涂覆、500℃退火工艺制得的膜层显示出较优的电池性能(Voc-430mV,Isc-150-215μA).
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 (Voc -430mV, Isc -150 215μA).