Photovoltaic and Interfacial Properties of Heterojunctions Containing Dye-Sensitized Dense TiO2 and Tri-arylamine Derivatives
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- 作者：Erik M. J. Johansson ; Patrik G. Karlsson ; Maria Hedlund ; Declan Ryan ; Hans Siegbahn ; Hå ; kan Rensmo
- 刊名：Chemistry of Materials
- 出版年：2007
- 出版时间：April 17, 2007
- 年：2007
- 卷：19
- 期：8
- 页码：2071 - 2078
- 全文大小：271K
- 年卷期：v.19,no.8(April 17, 2007)
- ISSN：1520-5002
文摘
A series of solid-state heterojunctions comprising a dense TiO2 film electrode as an electron conductor,a ruthenium polypyridine complex (Ru(dcbpy)2(NCS)2) as a light-absorbing dye, and different triarylaminederivatives as hole conductors were prepared, and their photovoltaic properties as well as the molecularand electronic interfacial structures were investigated. The photovoltaic properties were compared tosystems containing the hole conductors dissolved in an organic solvent as well as to a system containinga liquid electrolyte containing the iodide/tri-iodide redox couple. Two of the solid-state heterojunctionsshowed conversion efficiencies close to those of the system containing the iodide/tri-iodide redox couple,while one system was clearly less efficient. To explain the differences in photovoltaic properties theelectronic and molecular interfacial structures of the solid-state heterojunctions were investigated byphotoelectron spectroscopy (PES). By valence level PES the electronic energy levels highest in energyfor the dye and the hole conductors were mapped, and the differences in energy matching partly explainthe trends in photovoltaic properties. Differences in the molecular surface structure of the heterojunctionswere also observed from the N 1s core level measurements. Specifically it was found that the smallerhole conductor, showing low photocurrent yield, is inserted into the dye layer.