NOVELTY - A layer configuration (L) comprises a layer of a nano-porous n-type metal oxide semiconductor (A) with a band-gap of greater than 2.7eV, an adsorbed cationic spectral sensitizer (B) and a coadsorber (C). (C) Enhances the adsorption of (B) on (A).    USE - In photovoltaic device and in solar cell (claimed).    ADVANTAGE - The coadsorber enhances the adsorption of cationic spectral sensitizer on the n-type metal oxide semiconductor. Thus the semiconductor layer has an enhanced adsorption of cationic dye sensitizer and enhanced sensitization efficiency. The photovoltaic device containing the nanoporous semiconductor layer achieves a high short circuit current. The solar cell containing the nanoporous semiconductor layer achieves high conversion efficiency. PLACHGLAS AG (RTM; a glass substrate) was ultrasonically cleansed in ethanol for 5 minutes and dried. A layer of nano-TiO2 dispersion (Ti-nanoxide HT) was applied to the glass substrate using a doctor blade coater. The TiO2-coated glass was then heated to 450degreesC for 30 minutes to obtain a highly transparent nano-porous TiO2 layer having a dry layer thickness (mum) of 1.5, 3 or 5. The glass plate was then cooled to 150degreesC by placing the hot plate at 150degreesC for 10 minutes. The plate was then immediately immersed in a solution containing DC-06 (para-toluene sulfonic acid salt of 3-ethyl-2-(3-ethyl-3H-benzothiazol-2-ylidenemethyl)-benzothiazol-3-ium dye and an ortho-dihydroxy-benzene coadsorber for 15 - 17 hours. The layer was then rinsed with acetonitrile to remove non-adsorbed dye and then dried at 50degreesC for several minutes. A comparative nano-porous layer was prepared similarly, but without using the coadsorber. The lambdamax of the dyed TiO2-layer was 426 nm. Absorption spectra of the coated layers were then obtained at 200 - 800 nm. The absorbance at lambdamax of the dyed TiO2 test/comparative layers was found to be 0.72/0.2.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of (L) involving: adsorbing (C) and (B) on a layer of (A).