基于薄膜电极溶胶修饰的染料敏化太阳电池光电特性研究

Photoelectricity performance research based on the sol-modified thin film electrode of dye-sensitized solar cells

染料敏化太阳电池(DSC)中的纳米薄膜电极是决定太阳电池光电转换性能的重要组成部分.为改善薄膜电极特性,采用了不同浓度的TiO_2溶胶对DSC光阳极导电玻璃和纳米TiO_2多孔薄膜进行不同方式的界面处理.利用X射线衍射方法对制备得到的多孔薄膜以及溶胶经高温处理后致密层中纳米TiO_2颗粒的尺寸及晶型进行了测试.采用高分辨透射电子显微镜和场发射扫描电子显微镜观察了纳米颗粒及薄膜微结构形貌.采用强度调制光电流谱/光电压谱分析了TiO_2溶胶的不同处理方式对电子传输和复合的影响.在100 mW·cm^(-2)光强以及暗环境下分别测试了DSC的伏安输出性能以及暗电流.结果表明,不同浓度和处理方式均能较好地抑制暗电流.溶胶处理后光生电子寿命Υ_n延长,电子传输平均时间Td相应缩短.采用浓度为0.10 mol·L^(-1)的溶胶对导电玻璃和多孔膜同时处理,DSC的宏观输出特性最佳,短路电流密度J_(sc)提高了10.9%,光电转换效率η提高了11.9%.

Nanoporous film electrode is a crucial composition of dye-sensitized solar cells, which influences the photoelectric conversion performance. To improve the property of the photoelectrode, different modification methods by using different concentrations of TiO2 sol are investigated. The crystallite size and phase of the nanoporous TiO2 particles and the TiO2 sol after sintering are studied with X-ray diffraction. The microstructure morphologies of the conductive glass and the films are determined by the high resolution transmission electron microscopy and the field emission scanning electron microscopy. The influences on electron lifetime 7n and the electron transit time 7a are analyzed by intensity-modulated photocurrent spectroscopy and photovoltage spectroscopy from the mechanisms of electron transport and back reaction kinetics. It is found that the back reactions are well suppressed under dark conditions after sol modifications. Tn is effectively extended and d is also shorten correspondingly by any kind of sol treatment. The short-current density and the photoelectric conversion efficiency are increased by 10.9% and 11.9% separately, when 0.10 mol.L-1 sol modification is applied both to the conductive glass and to the nanoporous Ti02 film at the same time.