Rational use of ligand to shift the UV–vis spectrum of Ru-complex sensitiser dyes for DSSC applications

Publication date: August 2019Source: Radiation Physics and Chemistry, Volume 161Author(s): Frederick Backler, Gregory J. Wilson, Feng WangAbstractRadiation is energy travelling through space. Sunlight radiation such as ultraviolet (UV) radiation are higher-energy radiation which are used in medicine and energy industry such as dye sensitized solar cells (DSSCs). We recently designed new Ru-complexes through novel ligands based on a recently synthesised high performance dye, i.e. [(η6-p-cymene)Ru(4,4′,5,5′-H4tcbpy)Cl]Cl [1] (A as L1-Ru-L2) for applications in DSSCs. Two electron rich top-ligands, η6-N, N, N′, N′-tetramethyl-p-phenylenediamine (new dye D) and η6- 1,4 di[(dimethylamino)ethyl] benzene (new dye E) outperform other ligands for the new high performance Ru-complexes. Our time dependent density functional theory (TD-DFT) using the CAM-B3LYP/6-311G+(d)/LANL2DZ functional and basis-set model reveals the apparent enhancement of the major UV–vis bands of metal to ligand charge transfer (MLCT) in the new dyes. The major UV–vis bands of the new dyes D and E are red shifted 35 nm and 78 nm, respectively, from the MLCT band of the reference dye A centred at 433 nm. We further discovered that the electron rich top-ligands (L1) are responsible to lift a cluster of occupied outer valence orbitals such as HOMO, HOMO-1 and HOMO-2 in the new D and E complexes, while the virtual orbitals which concentrate on the lower ligand L2 (4,4′,5,5′ H4 tcbpy) remain al...

Source: Radiation Physics and Chemistry - April 17, 2019 Category: Physics Source Type: research