Investigation of electrodeposited cobalt sulphide counter electrodes and their application in next-generation dye sensitized solar cells featuring organic dyes and cobalt-based redox electrolytes

Sanjay Kumar Swami, Neha Chaturvedi, Anuj Kumar, Raman Kapoor, Viresh Dutta, Julien Frey, Thomas Moehl, Michael Grätzel, Simon Mathew, Mohammad Khaja Nazeeruddin

Research output: Contribution to journalArticlepeer-review

63 Scopus citations

Abstract

Cobalt sulphide (CoS) films are potentiodynamically deposited on fluorine-doped tin oxide (FTO) coated glass substrates employing one, three and five sweep cycles (CoS-I, CoS-III and CoS-V respectively). Analysis of the CoS-III film by impedance spectroscopy reveals a lower charge transfer resistance (RCT) than that measured for Pt CE (0.75 ω cm-2 and 0.85 ω cm-2, respectively). The CoS films are used as counter electrodes (CE) in dye-sensitized solar cells (DSSCs) featuring the combination of a high absorption coefficient organic dye (C218) and the cobalt-based redox electrolyte [Co(bpy)3]2/3+. DSSCs fabricated with the CoS-III CE yield the highest short-circuit current density (JSC) of 12.84 mA cm-2, open circuit voltage (VOC) of 805 mV and overall power conversion efficiency (PCE) of 6.72% under AM 1.5G illumination (100 mW cm-2). These values are comparable to the performance of an analogous cell fabricated with the Pt CE (PCE = 6.94%). Owing to relative lower cost (due to the inherit earth abundance of Co) and non-toxicity, CoS can be considered as a promising alternative to the more expensive Pt as a CE material for next-generation DSSCs that utilize organic dyes and cobalt-based redox electrolytes.

Original languageEnglish
Pages (from-to)80-89
Number of pages10
JournalJournal of Power Sources
Volume275
DOIs
StatePublished - 1 Feb 2015
Externally publishedYes

Keywords

  • Cobalt electrolyte
  • Cobalt sulphide
  • Counter electrode
  • Dye sensitized solar cell
  • Organic dye

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology
  • Physical and Theoretical Chemistry
  • Electrical and Electronic Engineering

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