Novel Ruthenium Complex with Terpyridine Derivative for DSSCs

Abstract

In this work, we designed and investigated theoretically novel ruthenium(II) complex (Bu4N)[Ru(DMFAdctpy)(NCS)(3)]; (DMFAdctpy : 2-(6-(5-(4-(bis(9,9-dimethyl-9H-fluoren-2-yl)amino)phenyl)pyridin-2-yl)-4-carboxypyridin-2-yl)pyridine-4-carboxylic acid) with DMFAdctpy as an anchoring group and a highly conjugated ancillary ligand to increase absorption ability in the long wavelength region compared to the N3 dye([Ru(dcbpy)(2)(NCS)(2)]); (dcbpy (4,4-dicarboxy-2,2-bipyridine)). The density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations were used to gain insight into the factors responsible for photovoltaic properties as dye sensitizer. The absorption spectrum of these dyes with terpyridine derivative is more red-shifted and broad than that of N3, especially, in the region between 400nm and 650nm. This is attributed to the extension of the -conjugated system of insertion terpyridine ligands. Molecular orbital analysis confirmed that the HOMOs of (Bu4N)[Ru(DMFAdctpy)(NCS)(3)] localized over the NCS ligand orbitals. The LUMO, LUMO+1 and LUMO+2 are mainly localized over the dctpy ligand. However, the LUMO+3 is delocalized on the DMFA moiety. Due to the panchromatic and red-shifted absorption spectrum, these novel ruthenium complexes are expected to good candidates as dye sensitizers for DSSCs.