Access to primary energy will clearly be a crucial problem already in the next few decades. Since the total solar energy that reaches the Earth exceeds our total energy consumption by a factor of ca 10 000, an attractive solution would be large scaleconversion of solar energy to electricity and fuel. In our group, we are developing new technologies to convert solar energy into either electricity or hydrogen by respective dye sensitized solar cells (DSSCs) and water splitting with inspiration from the active sites of Photosystem II and FeFe-hydrogenases. We draw upon the strong synergies that exist between these two fields of research: similar dye molecules, nanostructured semiconductors and electrolytes. For the solar cells project, we are searching a more profound understanding of how the different components of the DSSC interact, by investigating new types of dyes, semiconductors and electrolytes. We are also designing and synthesizing p-type DSSCs, paving the road for tandem solar cell systems and solid state polymer solar cells. For the water splitting project, we are developing a totally new system by adapting the DSSC technique to two half reactions (water oxidation and proton reduction). For proton reduction, the focus has been on bio-inspired molecular catalysts such as Fe2S2 complexes etc. For catalytic water oxidation, we are focusing on transition metal complexes such as Ru dimers. In addition, our group also conducts research work on supramolecular chemistry based on CBs and CDs in particular the light driven molecular devices.

Fluorescent dyes for the bio-imaging and bio-labeling
Novel fluorescent dyes and their photo-induced electron transfer, charge transfer and proton transfer are investigated. These dyes are used for the conjugation with bio-molecules for DNA sequencing, DNA chips, DNA molecular beacons, immunoassay and peptide analysis, and as selective and sensitive fluorescent intracellular chemosensors for cations (such as Zn2+, Cd2+, Cr3+ or H+), anions (such as F- and CH3CO2-) and small bio-molecules.
Photochemistry of supramolecules: Photo-induced electron transfer, charge transfer, and proton transfer
Supramolecules are designed in which dye is covalently linked to electron donor or acceptor. Photo-induced intermoleculear electron transfer (PET), phtoto-induced intermolecular charge transfer (ICT), and photo-induced proton transfer are used to improve the functional characters of the dyes as recognizing, sensing and reporting molecular devices. For example, ICT provides cyanine dyes large Stokes shift and excellent lightfastness.

Dye-sensitized solar cell based on nanostructure titania
Dye-sensitized solar cells (DSCs) have been attracting much attention due to their high-energy conversion efficiency and as a low-cost alternative to commercial solar cells based on silicon. In order to successfully commercialize DSCs, it is necessary to further improve the energy conversion efficiency and lifetime. Her group interests include the following fields: (1) The study of syntheses of new sensitizers and semiconductor; (2) The improving the efficiency of DSC by the N-doped titania electrodes; (3) The development of new counter electrodes; (4) The study of supermolecular photoelectric devices; (5) The studies of polymer dispersant for the industrial print of the thin film electrodes and the large area DSC; (6) The study of new tandem structure of DSC.
Hydrogen production by solar energy
Solar hydrogen production is very attractive way to harvest and store solar energy. It is well known that a combination process of photovoltaic cell and water electrolysis is a practical way to solar hydrogen production. We study in photocatalytic water splitting using oxide semiconductor powders. We are also carrying out solar hydrogen production using a system composed of an oxide semiconductor photoelectrode and a dye-sensitized solar cell.