Metal-free photosensitizers based on benzodithienothiophene as π-conjugated spacer for dye-sensitized solar cells

Kai Zhang, Weifeng Zhang, Jianyao Huang, Aiying Pang, Ricky M S WONG*

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

16 Citations (Scopus)


A novel series of metal-free organic photosensitizers based on D-π-A or D-A1-π-A structure motif namely, BD-n, (where n = 1–5) bearing a high hole-transporting benzodithienothiophene as the π-bridge for the first time, carbazole or triarylamine as the electron-donor and benzothiadiazole or quinoxaline as the auxiliary electron-deficient unit was synthesized and investigated for DSSC applications. DSSCs based on these five photosensitizers were also fabricated which exhibited efficiencies ranging from 3.92% to 5.46%. Among these DSSCs, devices based on D-A1-π-A type dye, BD-3 and bidenate dye, BD-5 as a photosensitizer afforded the best efficiencies of 5.34%–5.46%. Our results suggested that an incorporation of a proper auxiliary accepting group (A1) into the D-π-A conjugation system to enhance light harvesting and charge transfer as well as the use of V-shaped di-anchoring strategy to suppress aggregation on the TiO2 surface were found to be useful and effective strategies to enhance the photovoltaic performance of a DSSC. These devices exhibited relatively long electron lifetimes suggesting the slow charge recombination kinetics and thus better DSSC performance. Our findings also suggest that benzodithienothiophene is a promising π-bridge to construct organic photosensitizers for high-efficiency DSSCs.

Original languageEnglish
Pages (from-to)275-283
Number of pages9
JournalOrganic Electronics
Publication statusPublished - 1 Mar 2017

Scopus Subject Areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Chemistry(all)
  • Condensed Matter Physics
  • Materials Chemistry
  • Electrical and Electronic Engineering

User-Defined Keywords

  • Benzodithienothiophene
  • DSSC
  • Organic photosensitizers
  • π-spacer


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