三维有序大/介孔TiO_2反opal光阳极制备及光电性能

Three-dimensional ordered macro/mesoporous TiO_2 inverse opal electrode with enhanced dye-sensitized solar cells' efficiency

通过添加不同含量的造孔剂聚乙二醇2000(PEG2000),在二氧化钛反蛋白石结构(Ti O_2反opal)光阳极骨架结构中引入介孔结构,制备出了三维有序大/介孔Ti O_2反opal光阳极。用SEM和TEM表征了该光阳极的表面形貌,应用紫外可见光谱表征了其染料吸附-脱附性能,测试了基于该光阳极结构的染料敏化太阳能电池的光电转换特性和阻抗特性。结果表明,介孔结构的引入使Ti O_2反opal光阳极染料吸附能力增强,组装为染料敏化太阳能电池(DSSCs)后光电转换效率提高,电池交流阻抗降低。同时,随着PEG2000含量的增加,光电转换性能呈现先增加后减小的趋势,这可能来源于过量的PEG2000可造成宏孔骨架结构的破坏。

Three dimensional（3D） ordered macro/mesoporous titanium dioxide inverse opal（TiO_2-IO） electrodes were fabricated via a sol-gel method with polyethylene glycol（PEG2000） treatment. The effects of PEG2000-treatment on the formation of TiO_2-IO, the photovoltaic parameters and dye sensitized solar cells（DSSCs） efficiency were investigated. Macroporous templates with oval structures were prepared by using the self-assembly of monodispersed polystyrene（PS） microspheres. Titanium alkoxide precursors containing PEG2000（as the mesopore directing agent） were infiltrated into the macroporous templates. 3D ordered macro/mesoporous TiO_2-IO films were obtained after removing the PS and PEG2000 by calcinations. This kind of 3D macro/mesoporous electrode results in a better dye absorbtivity and enhanced DSSC efficiency. The experiments demonstrate that this enhanced efficiency not only results from active sites to adsorb dye, but also may lie in the decreased characteristic impedances of the DSSCs, which is attributed to the introduction of the mesopores in the TiO_2-IO electrode. However, an excessive quantity of PEG2000 results in a drop of photoelectric conversion efficiency because of the damage of the macroporous structure with excessive PEG-treatment.