title: A detailed study on the working mechanism of a heteropoly acid modified TiO2 photoanode for efficient dye-sensitized solar cells.
abstract: A novel heteropolyacid (HPA) K6SiW11O39Ni(H2O)·xH2O (SiW11Ni) modified TiO2 has been successfully synthesized and introduced into the photoanode of dye-sensitized solar cells (DSSCs). The performance of the cell with the HPA-modified photoanode (SiW11Ni/TiO2), mixed with P25 powder in the ratio of 2 : 8, is better than the cell with a pristine P25 photoanode. An increase of 31% in the photocurrent and 22% improvement in the conversion efficiency are obtained. The effect of the heteropolyacid was well studied by UV-vis spectroscopy, spectro-electrochemical spectroscopy, dark current, intensity-modulated photocurrent spectroscopy and intensity-modulated photovoltage spectroscopy, open-circuit voltage decay and electrochemical impedance spectroscopy. The results show that the interfacial layer modified by SiW11Ni can enhance the injection and transport of electrons, and then retard the recombination of electrons, which results in a longer electron lifetime. What's more, the introduction of SiW11Ni can simultaneously broaden the absorption in the visible region, eventually leading to an efficient increase in energy conversion efficiency.
authors: Department of Chemistry, Harbin Institute of Technology, Harbin, 150001, P. R. China. ylyang@hit.edu.cn fanruiqing@hit.edu.cn.
authors: Yanxia
authors: Y
authors: Jiang
authors: Yulin
authors: Y
authors: Yang
authors: Liangsheng
authors: L
authors: Qiang
authors: Ruiqing
authors: R
authors: Fan
authors: Liang
authors: L
authors: Li
authors: Tengling
authors: T
authors: Ye
authors: Yong
authors: Y
authors: Na
authors: Yan
authors: Y
authors: Shi
authors: Tianzhu
authors: T
authors: Luan
mesh_terms: D004396:Coloring Agents / Q000737:chemistry*; D058266:Dielectric Spectroscopy; D004566:Electrodes; D011789:Quantum Theory; D012993:Solar Energy; D014025:Titanium / Q000737:chemistry*; D017973:Tungsten Compounds / Q000737:chemistry; D000099294:Polyoxometalates
chemical_list: D004396:Coloring Agents; D014025:Titanium; D017973:Tungsten Compounds; C102296:polyoxometalate I; D000099294:Polyoxometalates; C009495:titanium dioxide