Research objectives and content
It is now possible to fabricate electrochemical photovoltaic devices based upon dye sensitised nanocrystalline titanium dioxide films. These novel solar cells are already in industrial production, offering the potential for a five fold drop in production costs compared to conventional silicon PV cells. The function of these composite material devices is based upon an interfacial electron transfer reaction from an optically excited dye molecule into the titanium dioxide, thus sensitising this wide bandgap semiconductor to visible light. However, lack of scientific knowledge about the electronic properties of this interface is limiting further technological development. For example, up to a two fold increase in device efficiency could be achieved by the use of sensitiser dyes with increased long wavelength absorption, but extensive empirical trials have as yet failed to identify any suitable alternative dyes. We therefore propose to conduct a systematic study of the dye sensitisation process in these devices, in order to identify those characteristics of the dye / semiconductor interface which are essential for efficient device function, and leading to the development of higher efficiency electrochemical solar cells. The sensitisation reaction occurs on ultrafast timescales, and therefore a key component of this project will be the application of ultrafast spectroscopic techniques to the elucidation of this problem. Training content (objective, benefit and expected impact)
acquiring a working knowledge of state-of-the-art ultrafast spectroscopy theoretical and experimental understanding of photoelectrochemistry development of independent research skills
Links with industry / industrial relevance (22)
Several European companies have expressed considerable interest in this kind of cells. In particular, this project will involve a collaboration with Johnson Matthey Ltd., U.K. concerning the development of phtalocyanines as sensisting dyes.