Synthesis, Structural Characterisation, and Spectroscopic Properties of Copper(I) Complexes and their Applications to Dye-Sensitised Solar Cells

Abstract

Based on the ligand 1,4-bis(2-(diphenylphophino)benzylideneamino)benzene (pbb), two complexes, [Cu2(pbb)(2,2′-bipyridine)2](BF4)2 (1) and [Cu2(pbb)(phen)2](BF4)2 (2), have been prepared and characterised by IR, 1H NMR, 31P NMR, 19F NMR, and 11B NMR spectroscopy and X-ray crystal structure analysis. Structural analysis reveals that complexes 1 and 2 contain 1D infinite chains and 2D supramolecular networks constructed by C–H···π and π···π interactions, and an ordered-layer-lattice of BF4– is located between these 2D networks. The results show that C–H···π and π···π interactions play an important role in the formation of 2D supramolecular networks. The UV-vis absorption peaks of complexes 1 and 2 display intraligand charge transfer and metal to ligand charge transfer (MLCT) absorption. Complexes 1 and 2 display efficient luminescent emission assigned to MLCT excited states, and the maximum emissions of these complexes in acetonitrile solution are different from those of the solid-state samples. In addition, complexes 1 and 2 have been exploited as sensitisers in dye-sensitised solar cells, and efficiencies are also observed.