Characterisation of a ruthenium bipyridyl dye showing a long-lived charge-separated state on TiO2 in the presence of I-/I3-

Keri L. McCall, Ana Morandeira, James Durrant, Lesley J. Yellowlees, Neil Robertson

Research output: Contribution to journalArticlepeer-review

Abstract

The control of the loss mechanism in a dye sensitised solar cell (DSSC) via recombination of the injected electron with the oxidised dye was investigated by incorporating a redox-active ligand, 6,7-bis(methylthio)tetrathiafulvalene dithiolate (TTF(SMe)2), into a ruthenium bipyridyl dye. A series of dyes with general formula [Ru(4,4'-R-bpy)2(TTF(SMe)2], where R = H, CO2Et and CO2H, were synthesised and characterised using electrochemistry, absorption and emission spectroscopy, spectroelectrochemistry and hybrid-DFT calculations. In addition, the performance of the acid derivative in a DSSC was investigated using IV measurements, as well as transient absorption spectroscopy. These complexes showed significant TTF-ligand character to the HOMO orbital, as deduced by spectroelectrochemical, emission and computational studies. Upon adsorption of the acid derivative to TiO2 a long-lived charge-separated state of 20 ms was observed via transient absorption spectroscopy. Despite this long-lived charge-separated state, the dye yielded extremely low DSSC efficiencies, attributed to the poor regeneration of the neutral dye by iodide. As a result, the complex forms a novel long-lived charge separated state that persists even under working solar cell electrolyte conditions.

Original languageEnglish
Pages (from-to)4138-4145
Number of pages8
JournalDalton Transactions
Volume39
Issue number17
DOIs
Publication statusPublished - 7 May 2010

Keywords

  • SENSITIZED SOLAR-CELLS
  • RICH DITHIOLATE LIGAND
  • RAY CRYSTAL-STRUCTURE
  • DONOR-ANTENNA DYES
  • ELECTROCHEMICAL PROPERTIES
  • SUPRAMOLECULAR CHEMISTRY
  • PT(II) COMPLEXES
  • TETRATHIAFULVALENES
  • DYNAMICS
  • FILMS

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