Ruthenium(ii) complexes incorporating carbazole–diazafluorene based bipolar ligands for dye sensitized solar cell applications. (5th June 2017)

• Record Type: Journal Article
• Authors: Sivakumar, Radhakrishnan; Recabarren, Rodrigo; Ramkumar, Sekar; Manivel, Arumugam; Alzate-Morales, Jans; Contreras, David; Manidurai, Paulraj
• Is Part Of: New journal of chemistry. Volume 41:Number 13(2017)
• Page Start: 5605
• Page End: 5612
• Publication Date: 2017-06-05
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/c7nj01019b
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : A new type of ruthenium sensitizers, S3 andS4, consisting of carbazole–diazafluorene based bipolar ancillary ligands have been synthesized and characterized for dye sensitized solar cells. Abstract : In this research work, new types of ruthenium sensitizers used in dye sensitized solar cells (DSSCs), namedS3 andS4, consisting of carbazole–diazafluorene based bipolar ancillary ligands, have been synthesized and characterized by 1 H NMR, UV-vis absorption spectroscopy, and elemental analysis. The energy levels and band gaps of the sensitizers were evaluated using electrochemical measurements and density functional theory (DFT) calculations. Both sensitizers show blue shifted low energy metal to ligand charge transfer bands, which could be ascertained from the relatively large dihedral angle between the secondary electron donor (carbazole) and acceptor (4, 5-diazafluorene) units. The frontier molecular orbital surfaces obtained from DFT calculations revealed that the highest occupied molecular orbitals (HOMOs) of both sensitizers are dominantly populated on the secondary electron donor carbazole antenna, indicating the increased spatial separation of the HOMO away from the TiO2 surface. The DSSC fabricated using sensitizerS4 exhibited a higher photon-to-current conversion efficiency (2.11%) and these results were compared to those obtained with commercial sensitizerN719 . The implications of this study may contribute to the design of new molecular architectures to be applied in DSSCs.