0900 - 0940 Michael Gratzel

Optimizing photon harvesting and carrier collection in mesoscopic solar energy conversion systems

The performance of solar energy conversion devices employing mesoscopic photoelectrodes depends critically on the nanostructure. This is evident for the dye sensitized solar cell (DSC) where charge percolation through the nanocrysalline TiO₂ frim to the transparent conductive (TCO) electrodes takes milliseconds. Slow charge extraction increases chances of electron-hole recombination at the mesoporous TiO₂ - electrolyte interface, and limits DSCs to be used with only a handful of electrolytes that offer low recombination rates. These limitations can be overcome with advanced nanostructuring techniques and sensitizer design. Here we describe our latest advances in optimizing the photon harvesting and the charge transport in these mesoscopic energy conversion systems which have reached power conversion efficiencies (PCE) over 12 percent under AM 1.5 standard reporting conditions. Impressive progress has also been made in the cleavage of water into hydrogen and oxygenby visible light on mesoscopic inorganic semiconductor films, in particular iron oxide (hematite) and these rescent results will be presented.

References

M.Grätzel « Recent advances is mesoscopic solar cells » Acc. Chem. Res. 42, 1781-1798 (2009).