Dye-Sensitized Nanocrystalline Titanium-Oxide-Based Solar Cells Prepared by Sputtering: Influence of the Substrate Temperature During Deposition

Nanocryst. titanium oxide films were prepd. by DC magnetron sputtering onto SnO2:F-coated glass substrates kept at temps. in the 50 < τs < 300° range. Dye sensitization in cis-dithiocyanato-bis(2,2'-bipyridyl-4,4'-dicarboxylate) ruthenium(II) yielded solar cells with a conversion efficiency η. The dye incorporation was dependent upon τs, and an optimum value of η = 1.7% was found with ∼ 0.8-μm-thick titanium oxide films prepd. at 250°. The microstructure then displayed a well-defined parallel penniform pattern, and the luminous transmittance was 42%. The crystallite size was substantially enlarged at τs > 250°, and η showed an ensuing decrease.