Thiocyanate-Free Ru(II) Sensitizers with a 4,4 ′ -Dicarboxyvinyl-2,2 ′ -bipyridine Anchor for Dye-Sensitized Solar Cells

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

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Author(s)

  • Kuan-Lin Wu
  • Wan-Ping Ku
  • Sheng-Wei Wang
  • Aswani Yella
  • Shih-Hung Liu
  • Pi-Tai Chou
  • Mohammad K. Nazeeruddin
  • Michael Grätzel

Detail(s)

Original languageEnglish
Pages (from-to)2285-2294
Journal / PublicationAdvanced Functional Materials
Volume23
Issue number18
Online published10 Dec 2012
Publication statusPublished - 13 May 2013
Externally publishedYes

Abstract

A new class of thiocyanate-free Ru(II) sensitizers with 4,4′-dicarboxyvinyl-2,2′-bipyridine anchor and two trans-oriented pyrid-2-yl pyrazolate (or triazolate) functional chromophores is synthesized, characterized, and evaluated in dye-sensitized solar cells (DSCs). Despite their enhanced red response and absorptivity when compared to the parent sensitizer TFRS-2 that possesses standard 4,4′-dicarboxyl-2,2′-bipyridine anchor and shows the best conversion efficiency of η = 9.82%, the newly synthesized carboxyvinyl-pyrazolate sensitizers, TFRS-11-TFRS-13, exhibit inferior performance characteristics in terms of short-circuit current density (JSC), open-circuit voltage (VOC), and power conversion efficiency (η), the latter being recorded to be in the range 5.60-7.62%. The reduction in device efficiencies is attributed to a combination of poor packing of these sensitizers on the TiO2 surface and less positive ground-state oxidation potentials, which, respectively, increase charge recombination with I3- in electrolytes and impede the regeneration of sensitizers by I- anions. The latter obstacle can be circumvented in part by the replacement of the pyrazolates with triazolates, forming the TFRS-14 sensitizer, which exhibits an improved JSC, VOC, and η of 16.4 mAcm-2, 0.77 V, and 9.02%, respectively. 

Research Area(s)

  • anchoring ligands, dye-sensitized solar cells (DSCs), pyrazole, Ru sensitizers, triazole

Citation Format(s)

Thiocyanate-Free Ru(II) Sensitizers with a 4,4 ′ -Dicarboxyvinyl-2,2 ′ -bipyridine Anchor for Dye-Sensitized Solar Cells. / Wu, Kuan-Lin; Ku, Wan-Ping; Wang, Sheng-Wei; Yella, Aswani; Chi, Yun; Liu, Shih-Hung; Chou, Pi-Tai; Nazeeruddin, Mohammad K.; Grätzel, Michael.

In: Advanced Functional Materials, Vol. 23, No. 18, 13.05.2013, p. 2285-2294.

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