Earth-abundant iron oxysulfide (FeSxOy) for bandgap optimization

X. Han, B. Zhou, Meng Tao

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations

Abstract

Transition metal sulfides with small bandgap are attractive for solar cell applications since most transition metals are abundant and many can be deposited in solution. Pyrite FeS2, with a bandgap of 0.95 eV, is one of the most desirable for solar cell applications. The problem with FeS2 is that its bandgap is ∼0.45 eV smaller than the optimum bandgap for maximum efficiency, which should be ∼1.4 eV. In this paper, we propose the concept of metal oxysulfide as the approach to a low-cost Earth-abundant semiconductor with a direct bandgap of ∼1.4 eV for terawatt-scale solar cells. This is because the bandgap of Fe2O3 is 2.2 eV. By introducing O into FeS2, the bandgap should increase. In our experiments, we use oxidation of electrodeposited FeSx for this purpose. FeSx films were electrodeposited on FTO-coated glass. Post-deposition annealing was carried out in vacuum to make FeSx films denser and more stable in air. SEM and EDX confirm that the as-grown FeSx film is amorphous and the S/Fe ratio in the film is slightly above 1. Oxidation of the FeS x films was performed either in a tube furnace under air or electrochemically in an electrolyte. After oxidation, the bandgap in the resultant FeSxOy is ∼1.3 eV by electrochemical oxidation and ∼1.1 eV by thermal oxidation. Further optimization is expected to produce a FeSxOy with a ∼1.4 eV bandgap.

Original languageEnglish (US)
Title of host publicationProgram - 38th IEEE Photovoltaic Specialists Conference, PVSC 2012
Pages2528-2532
Number of pages5
DOIs
StatePublished - Nov 26 2012
Event38th IEEE Photovoltaic Specialists Conference, PVSC 2012 - Austin, TX, United States
Duration: Jun 3 2012Jun 8 2012

Publication series

NameConference Record of the IEEE Photovoltaic Specialists Conference
ISSN (Print)0160-8371

Other

Other38th IEEE Photovoltaic Specialists Conference, PVSC 2012
CountryUnited States
CityAustin, TX
Period6/3/126/8/12

Keywords

  • bandgap
  • iron sulfide
  • light absorber
  • oxysulfide

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Industrial and Manufacturing Engineering
  • Electrical and Electronic Engineering

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  • Cite this

    Han, X., Zhou, B., & Tao, M. (2012). Earth-abundant iron oxysulfide (FeSxOy) for bandgap optimization. In Program - 38th IEEE Photovoltaic Specialists Conference, PVSC 2012 (pp. 2528-2532). [6318109] (Conference Record of the IEEE Photovoltaic Specialists Conference). https://doi.org/10.1109/PVSC.2012.6318109