染料敏化太阳能电池中SrCO_3包覆TiO_2电极的界面特性研究

Study on Interfacial Characteristics of TiO_2 Electrode Coated by Strontium Carbonate in Dye Sensitized Solar Cells

用水热法制备TiO2纳米材料,并对TiO2表面进行修饰。通过场发射扫描电子显微镜(SEM)和光电子能谱(XPS)对材料表面结构和成分进行分析。结果表明TiO2薄膜表面包覆了一层粒径较大的SrCO3颗粒,整个电极表面呈现均匀的多孔结构。使用电化学工作站对电池进行光电性能分析和EIS测试,由I-V曲线的结果可得,修饰后的电极性能更优越,短路电流提高了39.9%,光电转化效率提高了38.3%。由电化学阻抗谱(EIS)测试结果可以看出,修饰后TiO2/dye/电解质的界面阻抗大于修饰前,说明包覆层在一定程度上起到了阻碍电荷复合的作用,从而减小了暗电流。

TiO2 nanomaterial was prepared by hydrothermal method. A surface modification was carried out. Surface structure and composition were analyszed by scanning electron microscopy （SEM） and X-ray photoelectron spectroscopy （XPS）. The results showed that a layer of SrCO3 with larger particles was coated on TiO2 thin film and the electrode surface remained homogeneous porous structure. Photoelectric performance and electrochemical impedance spectroscopy （EIS） were tested by electrochemical workstations. The current-voltage （l-V） curve revealed that the short-circuit current and photoelectric conversion efficiency enhanced by 39.9% and 38.3% respectively more than before. The EIS showed that the resistance of TiO2/dye/electrolyte interface of modified electrode was much larger than before. The results indicated that the layer of SrCO3 suppressed charge recombination reactions and reduced the dark current.