Prof Henry Snaith FRS

Abstract:

In-plane 'hole-only' and 'electron-only' devices were fabricated and the the conductivity was selectively measured through the TiO2 and the Spiro-MeOTAD. The hole conductivity through the composite was approximately three times higher than the electron conductivity. The mobility of TiO 2 decreases as the illumination intensity was increased towards intensities comparable with full sunlight. The effective diffusion coefficient for electrons reduced considerably as the light intensity approached solar illumination intensities, with the diffusion length becoming shorter than the film thickness.

Abstract:

We compare a series of molecular sensitizers in dye-sensitized solar cells containing the organic hole transporter 2,2',7,7'-tetrakis(N,N-di-p-methoxypheny-amine)-9,9'-spirobifluorene (spiro-MeOTAD). Charge recombination is reduced by the presence of "ion-coordinating" moieties on the dye, with the longest electron lifetime and highest solar cell efficiency achieved using a novel sensitizer with diblock alkoxy-alkane pendent groups. By further increasing the optical path length in the active layer, we achieve a power conversion efficiency of over 5% under simulated sun light.

Abstract:

This Progress Report highlights recent developments in dye-sensitized solar cells composed of both liquid electrolytes and solid-state hole transport materials. The authors discuss and review the present understanding of and recent developments in the operational processes, such as charge generation, transport, recombination, and charge collection. Also, the merits and challenges of alternative device approaches are discussed, including extremely thin absorber cells, device containing inorganic p-type hole-transporters and non-TiO2 mesoporous metal-oxide electrodes employed in dye-sensitized solar cells. © 2007 WILEY-VCH Verlag GmbH & Co. KGaA.