Ru-dye grafted CdS and reduced graphene oxide Ru/CdS/rGO composite: An efficient and photo tuneable electrode material for solid state dye sensitized polymer solar cells

•CdS/rGO composite was grafted with Ru dyes to make ternary composite (Ru/CdS/rGO).•Carboxylic acid functionality played a key role in the formation of ternary composite.•Grafting of Ru dyes on the surface of CdS/rGO extended absorption to visible region.•Ternary composite boosted the efficiency of fabricated devices.

This article provides a facile one step synthesis of CdS (cadmium sulphide) and CdS/rGO (reduced graphene oxide CdS nanocomposites) using DMF (N, N-Dimethyl formamide) both as a solvent and a reducing agent for the reduction of grapheme oxide. XRD (X-ray diffraction), FESEM (Field emission scanning electron microscopy), EDX (Elemental dispersive X-ray analysis), TEM (Transmission electron microscopy), UV-Vis (UV-visible) and Raman spectroscopy have been employed for the characterization of prepared samples. The prepared nano-composite was photosensitized with three well known Ru (Ruthenium) dyes i.e. N3 [cis-Bis(isothiocyanato) bis(2,2′-bipyridyl-4,4′-dicarboxylato ruthenium(II))], N719 [Di-tetrabutylammoniumcis-bis(isothiocyanato)bis(2,2′-bipyridyl-4,4′-dicarboxylato) ruthenium (II)] and Z907 [cis-Bis(isothiocyanato)(2,2′-bipyridyl-4,4′-dicarboxylato)(4,4′-di-nonyl-2′-bipyridyl)ruthenium(II)]. The effect of concentration and number of anchoring groups on the grafting was extensively studied in order to explore structure-activity relationship. Photosensitization of CdS/rGO nanocomposite was evidenced by UV-Visible, PL (Photoluminiscence), FT-IR (Fourier transform infra-red) spectroscopy and I-V (current-voltage measurements). The prepared samples were found as effective electrode materials for application in SSDSSCs (solid state dye sensitized solar cells) with a maximum output efficiency of 1.01% which is two times higher than the reference device under the same experimental conditions. The components of the synthesized nanohybrid material were found to be capable of providing a uni-directional and cascade path for the flow of electrons and holes in the desired directions.

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