Geometrical Isomerism of RuII Dye-Sensitized Solar Cell Sensitizers and Effects on Photophysical Properties and Device Performances

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Author(s)

  • Fa-Chun Hu
  • Sheng-Wei Wang
  • Neil Robertson
  • Tracy Hewat
  • Yue Hu
  • Shih-Hung Liu
  • Pi-Tai Chou
  • Po-Fan Yang
  • Hao-Wu Lin

Detail(s)

Original languageEnglish
Pages (from-to)1207-1215
Journal / PublicationChemPhysChem
Volume15
Issue number6
Online published13 Feb 2014
Publication statusPublished - 14 Apr 2014
Externally publishedYes

Abstract

To supplement our study on thiocyanate-free ruthenium sensitizers (TFRS) for dye-sensitized solar cells (DSSCs), which belong to a class of RuII-based complexes coordinated by a single 4,4′-dicarboxylic acid-2,2′-bipyridine and two symmetrically arranged functionalized trans-azolate chelates, we carefully isolated and characterized the second and less-abundant stereoisomer, in which the two pyridyl azolate ancillaries are asymetrically cis-arranged to each other. Two distinctive ancillaries, namely: 5-[4-(5-hexyl-2-thienyl)-2-pyridinyl]-3-trifluoromethyl pyrazole and 5-(6-tert-butyl-1-isoquinolinyl)-3-trifluoromethyl pyrazole, were employed in this study, giving a total of four sensitizers, that is, thienyl substituted TFRS-2 a and 2 b, and isoquinolinyl substituted TFRS-52 a and 52 b, in which the suffix b indicates the cis-stereoisomers. To gain insight into their fundamental properties their photophysical, electrochemical, and spectroelectrochemical behavior was investigated by density functional theory. Upon comparison of the correspondingly fabricated DSSCs, the sensitizers TFRS-2 a and 52 a yielded significantly higher conversion efficiencies than their asymmetrical cis-counterparts, TFRS-2 b and 52 b. To rationalize the cell performances charge extraction/photovoltage decay and impedance spectroscopic measurements were carried out to compare the rates of interfacial electron recombination from the TiO2 conduction band to the electrolyte.

Research Area(s)

  • density functional theory, dye-sensitized solar cells, pyrazolates, ruthenium, spectroelectrochemistry

Citation Format(s)

Geometrical Isomerism of RuII Dye-Sensitized Solar Cell Sensitizers and Effects on Photophysical Properties and Device Performances. / Hu, Fa-Chun; Wang, Sheng-Wei; Chi, Yun; Robertson, Neil; Hewat, Tracy; Hu, Yue; Liu, Shih-Hung; Chou, Pi-Tai; Yang, Po-Fan; Lin, Hao-Wu.

In: ChemPhysChem, Vol. 15, No. 6, 14.04.2014, p. 1207-1215.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review