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染料敏化太阳电池(DSSC)光阳极的研究
Research of Photoanode in Dye-Sensitized Solar Cells (DSSC)
【作者】 陈东坡;
【作者基本信息】 河北工业大学 , 材料物理与化学, 2011, 硕士
【摘要】 本文以染料敏化太阳电池光阳极的各组成部分(导电玻璃、阻挡层、多孔TiO2薄膜,散射层)为研究对象,以提高该类电池的性价比为最终目标,采用Docter-blade方法制作多孔TiO2薄膜,然后浸染料24小时,加入电解质后和铂对电极组装成电池。采用X射线光电子能谱(XPS)、X射线衍射(XRD)、场发射扫描电子显微镜(FE-SEM)、紫外可见分光分光度计(UV-Vis)以及透射电子显微镜(TEM)对光阳极的性能进行表征,并在AM1.5和暗环境下测试了电池的光电性能,得到了如下结论:(1)用不同浓度的TiCl4水解可以在光阳极导电玻璃基底FTO上获得由TiO2粒子组成的阻挡层薄膜,阻挡层薄膜的形貌、厚度随TiCl4溶液浓度的改变而改变;用0.04mol/L的TiCl4溶液所制备的阻挡层对暗电流的抑制最为明显,此时电池的光电转换效率为7.84%。(2)透明导电薄膜IWO的表面比较平滑,电解液的浸泡不会对形貌产生影响;经高温退火,IWO薄膜的方块电阻变大;可见光范围内,FTO的透过率整体上大于IWO;将FTO和IWO用于染料电池,用FTO所做电池的短路电流、开路电压、填充因子和光电转换效率要比IWO的高。(3) 200nm和400nm的TiO2粒子制做的散射层能提高多孔TiO2薄对光的漫反射、吸收和绒度,用200nm的粒子制作散射层时所得电池的性能更好一点。(4) TiO2粒子分别经过盐酸和硝酸处理后,它的分散性会得到提高;对染料的吸附量增加,表面态发生变化,用处理后的TiO2粒子所做电池的短路电流和效率都会提高,而HCl处理过的电池性能要比HNO3处理过的好。
【Abstract】 In order to improve the cost-effective of dye-sensitized solar cells, every part of photoanode electrodes, including transparent conducting glasses, porous TiO2 thin film, scatting layers, were chosen as our research object in this paper. We utilized the technique of doctor-blade to prepare porous TiO2 film, then dipped it into dye solution for 24 hours, after that, the electrolyte was immersed into TiO2 film, at last, we assembled dye-covered TiO2 electrode and Pt-counter electrode into a DSSC. The performances of photoanode electrodes were characterized by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM), UV-visible spectrophotometer, and transmission electron microscopy (TEM), the photovoltaic performances of dye-sensitized solar cell (DSSC) were measured under AM1.5 illumination and dark conditions, respectively. The conclusions are revealed as follows:The first, blocking layer thin films consisted of TiO2 particles were prepared on a conductive fluorine-doped tin oxide (FTO) substrate by hydrolysis of TiCl 4 solution with different concentrations, Increasing in the concentration of TiCl4 solution leads to an increase in the blocking layer thickness as well as variation of its morphology; the blocking layers prepared by TiCl 4 solution of 0.04 mol/L can suppress the dark current most efficiently and give rise to the highest power conversion efficiency of 7.84% under AM1.5 illumination conditions.The second, the surface of IWO thin films is smoother than FTO’s, when dipped into electrolyte, its surface morphology can’t be affected; the sheet resistance of IWO thin films becomes larger after annealing in the air; the transmittance of FTO is better than the one of IWO in visible region, we use FTO and IWO as the substrate of DSSC, it is revealed that the current density, photo- voltage, fill factor and conversion efficiency of DSSC composed of FTO are higher than the ones of IWO. The third, The scattering layers, composed of 200 nm and 400 nm TiO2 particles, can enhance the reflectance, absorbance of sunlight in porous titanium dioxide thin films, and the haze of them, the photovoltaic performances of the DSSC containing 200nm TiO2 particles are better than that containing 400nm TiO2 particles.The fourth, the dispersion of titanium dioxide particles will be improved, the amount of adsorbed dye molecules is increased, there will be changes in the surface states, when they are treated with hydrochloric acid and nitric acid, separately. The short current density and power conversion efficiency of DSSC composed of these treated particles are inhanced, in addition, it is proved that HCl-treated DSSC is superior to that of the HNO3-treated one.
【Key words】 TiO2 thin films; blocking layers; scattering layers; amount of adsorbed dye molecules; dye-sensitized solar cells;