Facile fabrication of mesoporous TiO2 electrodes for dye solar cells:: chemical modification and repetitive coating

A chemical dispersing technique for preparing a coating paste of TiO2 nanoparticles is disclosed to fabricate mesoporous electrodes for dye-sensitized TiO2 solar cells. The suspension of TiO2 (P-25) powder was stirred in aqueous nitric acid at 80degreesC, and then evaporated to dryness, giving the nitric acid-adsorbed P-25 powder. The coating paste was obtained by mixing the nitric acid-adsorbed P-25 with PEG (M-W 20,000) as a porosity-controlling agent and cellulosic polymer as a thickener. The mesoporous TiO2 films were fabricated on conducting glasses by repetitive coating and calcined at 500degreesC (30 min). The TiO2 film obtained by the five times repetitive coating (20 pm thickness) resulted in the 1.4 times higher energy conversion efficiency of the dye-sensitized solar cells than that of the one time coating TiO2 film (V-OC = 690 mV, J(SC) = 12.2 mA/cm(2), the fill factor = 0.71 and eta = 6.0%). (C) 2002 Elsevier Science B.V. All rights reserved.