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In a novel approach, fullerene, C 60 was attached to N3 dye ( cis -bis(4,4′-dicarboxy-2,2′-bipyridine)dithiocyanato ruthenium(II)) via diaminohydrocarbon linkers (L) with different carbon chain lengths. The resulting complexes (each designated as N3-L-C 60 ) were characterized by FT-IR spectra, FE-SEM images, and EDX analysis. The short-circuit photocurrent density ( J sc ) of the dye-sensitized solar cells (DSSCs) using the fullerene-attached sensitizers varied markedly depending on the chain length of the linker. In the case of the linker 1,6-diaminohexane, the J sc , V oc and conversion efficiency of the pertaining cell were found to be 11.75 mA/cm 2 , 0.70 V and 4.5%, respectively, as against the values of 10.55 mA/cm 2 , 0.68 V and 4.0%, respectively, for a DSSC with ordinary N3 dye. The J sc variations are discussed on the basis of effective dye adsorptions on TiO 2 films. The possible favorable effects for V oc enhancement, caused by hydrophobic atmosphere around the TiO 2 particles due to diaminohydrocarbon chains and by the negative shift of the flat band potential of TiO 2 by NH groups, are offset by the mediation of back electron transfer by C 60 ; this phenomenon is seen as the reason for minimal V oc changes. |
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