Novel ruthenium multi carboxylic complexes (RMCCs) have been synthesized by using ruthenium nitrosyl nitrate, 1,2,4,5-benzenetetracarboxylic acid (H4btec) and 4,7-diphenyl-1,10-phenanthroline (BPhen) as photosensitizers for titanium dioxide semiconductor solar cells. The complexes were characterized by (1)H-NMR, FT-IR, UV-Vis, ICP and CHN analyses. The reaction details and features were then described. SEM analysis revealed that the penetration of dyes into the pores of the nanocrystalline TiO2 surface was improved by increasing the number of btec units. The solar energy to electricity conversion efficiency of complexes shows that the number of attached carboxylates on a dye has an influence on the photoelectrochemical properties of the dye-sensitized electrode. An incident photon-to-current conversion efficiency (IPCE) of 13% at 510 nm was obtained for ruthenium complexes with three btec units.

The reactions of a zirconium salt with 1,2,4,5-benzenetetracarboxylate (btec), bathophenanthroline (Bphen) and thiocyanate ions were synthesized and studied by changing the mole ratio, the order of reactant and their pH. It is found that the coordination mode of btec acid depends on the control of reaction conditions. Monodentate, bidentate and bridging modes were investigated by FT-IR spectroscopy. The structures of Zr(btec) and Zr(btec)(Bphen) complexes were also characterized by UV-Vis, CHN, ICP-AES, (1)H NMR and cyclic voltammetry. The role of Bphen ligand in the photopysical properties of Zr(btec)(Bphen) complexes was investigated by DFT calculation. The photoluminescence (PL) emission of nine Zr(btec) complexes that have two peaks, a sharp and intense band for the first peak from 320 to 430 nm in comparison to the second peak with a less intensity and broadened in the regions of 650-780 nm. PL spectra of twelve Zr(btec)(Bphen) complexes also showed bands at 450, 550, 625 nm. LED devices with Zr complex as emitter layer and the structure ITO/PEDOT:PSS/PVK:PBD/zirconium complex/Al emitted a broad band centered at 550 and 650 originating from the Zr complexes. The EL spectra of Zr(btec) and Zr(btec)(Bphen) complexes indicated a long red shift rather than PVK:PBD blend. We believe that the electroplex occurring at PVK-Zr complexes interface is responsible for the green-red emission in the EL of the device. These observations suggest an important role for the Bphen ligand to improve EL performance.

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A series of heteroleptic ruthenium(II) complexes from Ru(NO)(NO3)3 as precursor have been designed, synthesized, and characterized by 1H-NMR, FT-IR, UV–Vis, PL, ICP and CHN analyses. The reaction details and features were described in detail. Solar cells involving thin films of anatase TiO2 impregnated with these dyes were prepared using an electrolyte solution of I-/I3- in acetonitrile as the electron mediator, and their photovoltaic performance was evaluated. The system lacking carboxyl moiety as anchoring groups shows poor photovoltaic performance. We found that the efficiency of cell is strongly affected by the presence of carboxyl groups of the sensitizing dye, the efficiency of 1,2,4,5-benzentetracarboxylic acid(btec) ruthenium(II) (with three btec moieties) adsorbed on nanocrystalline TiO2 films being 4 times as large as that of bahtophenathrolin ruthenium(II) (with one nitrato group) adsorbed on the same films . An incident photon-to-current conversion efficiency (IPCE) of 8% at 510 nm was obtained for tris(1,2,4,5-benzentetracarboxylic acid) ruthenium(II) (4)