SOLID-STATE DYE-SENSITIZED MESOPOROUS TIO2 SOLAR-CELLS WITH HIGH PHOTON-TO-ELECTRON CONVERSION EFFICIENCIES

Solar cells based on dye-sensitized mesoporous films of TiO2 are low-c ost alternatives to conventional solid-state devices' Impressive solar -to-electrical energy conversion efficiencies have been achieved with such films when used in conjunction with liquid electrolytes(2), Pract ical advantages may be gained by the replacement of the liquid electro lyte with a solid charge-transport material. Inorganic p-type semicond uctors(3,4) and organic materials(5-9) have been tested in this regard , but in all cases the incident monochromatic photon-to-electron conve rsion efficiency remained low. Here we describe a dye-sensitized heter ojunction of TiO2 with the amorphous organic hole-transport material ( N,N-di-p-methoxyphenyl-amine)9,9'-spirobifluorene (OMeTAD; refs, 10 an d 11). Photoinduced charge-carrier generation at the heterojunction is very efficient, A solar cell based on OMeTAD converts photons to elec tric current with a high yield of 33%.