天然染料作为Zn_2TiO_4太阳能电池敏化剂的研究

Study of natural dyes as photosensitizes for nanocrystalline Zn_2TiO_4 solar cell

从植物的叶、花、果实和果皮中提取出7种天然染料,通过对它们的UV-vis吸收光谱比较发现,从月季叶中提取的染料表现出较好的光响应性。采用溶胶-凝胶法制备了纳米晶Zn2TiO4薄膜电极,并利用X射线衍射(XRD)、扫描电镜(SEM)对其晶相及表面形貌进行了表征;制备了月季叶染料敏化Zn2TiO4电极,并以此为光阳极组装了Zn2TiO4太阳能电池;测定了上述敏化电极的吸收光谱以及电池的工作特性曲线。结果表明,月季叶染料吸附到Zn2TiO4薄膜上与染料在乙醇溶液中相比较,染料的吸收带变宽且最大吸收波长向红外方向发生了移动,月季叶染料在与Zn2TiO4结合后表现出一定的电子转移特性,并能很好地敏化Zn2TiO4电极;在模拟太阳光下,该电池开路电压为94.5 mV,短路电流为11.5μA,填充因子0.285和最大输出功率为0.309μW。

The seven kinds of natural dyes were extracted from flowers,leaves,fruits and peels,and were measured their optical absorption characteristics by U-2001 spectrophotometer.By comparison,it was found that the natural dye extracted from leaves of Chinese rose showed better performance of the light response.Nano-crystalline Zn2TiO4 film electrode were prepared by sol-gel method and were characterized by XRD and SEM.Using the natural dye extracted from leaves of Chinese rose as sensitizers,the natural dye sensitized Zn2TiO4 electrode was prepared,and the natural dye sensitized Zn2TiO4 solar cell device was fabricated.The absorption spectra of the sensitized electrode was characterized by Uv-2550 spectrophotometer,the result showed that the UV-Vis absorption bands of the adsorbed dyes onto Zn2TiO4 film are broadened and the corresponding maxima are red shifted with respect to its solution,and the natural dye presented a little ability of electron transfer and could well sensitize Zn2TiO4 film electrode.Current potential curve for the natural dye sensitized solar cell was tested under simulation sunlight,encouraging results were obtained with the extract of leaves of Chinese rose,achieving an open-circuit voltage of 94.5 mV,a short-circuit photocurrent of 11.5 μA,a fill factor of 0.285 and a maximum power output of 0.309 μW.