Fabrication of CuInS2 films from electrodeposited Cu/In bilayers: effects of preheat treatment on their structural, photoelectrochemical and solar cell properties

Phys Chem Chem Phys. 2011 Apr 14;13(14):6662-9. doi: 10.1039/c0cp02204g. Epub 2011 Mar 7.

Abstract

Polycrystalline CuInS(2) films were fabricated by sulfurization of electrodeposited Cu and In metallic precursor films in a Cu-rich composition at 520 °C in H(2)S (5% in Ar). Structural analyses revealed that the adherence of the thus-formed CuInS(2) film to the Mo substrate was strongly dependent on heating profiles of the Cu/In bilayer film: a CuInS(2) film with poor adherence having many crevices was formed when the Cu/In bilayer film was heated monotonously from room temperature to 520 °C in Ar within 25 min followed by sulfurization, whereas CuInS(2) films with good adherence were obtained when the Cu/In films were pretreated at 110 °C in Ar for 10-60 min just before increasing the temperature up to 520 °C for sulfurization. It was also clarified that the CuInS(2) film obtained without 110 °C pretreatment had pinholes inside the film, whereas the CuInS(2) films formed after 110 °C pretreatment showed no notable pinholes. Photoelectrochemical responses of these CuInS(2) films in an electrolyte solution containing Eu(III) indicated that the CuInS(2) films obtained after 110 °C pretreatment had higher external quantum efficiency (EQE) values than those of films obtained without 110 °C pretreatment, mainly due to better adherence of 110 °C pretreated CuInS(2) films to the Mo substrate than the CuInS(2) film obtained without 110 °C pretreatment. The performance of solar cells with an Al:ZnO/Zn(S,O)/CdS/CuInS(2)/Mo structure also depended on the structural characteristics of the CuInS(2) films, i.e., preliminary conversion efficiencies of ca. 5% were obtained for devices based on the CuInS(2) films obtained after 110 °C pretreatment, whereas the device prepared by the CuInS(2) film without 110 °C pretreatment showed the conversion efficiency less than 1.5%.

MeSH terms

  • Chemical Phenomena
  • Copper / chemistry*
  • Electric Power Supplies*
  • Electrochemistry
  • Electroplating*
  • Hot Temperature*
  • Indium / chemistry*
  • Molybdenum / chemistry
  • Optical Phenomena
  • Photochemical Processes*
  • Selenium / chemistry*
  • Solar Energy*
  • Sulfur / chemistry

Substances

  • copper indium diselenide
  • Indium
  • Sulfur
  • Copper
  • Molybdenum
  • Selenium