Stability and Electronic Structures of CuxS Solar Cell Absorbers: Preprint

Suhuai Wei

Research output: Contribution to conferencePaper

Abstract

CuxS is one of the most promising solar cell absorber materials that has the potential to replace the leading thin-film solar cell material Cu(In,Ga)Se2 for high efficiency and low cost. In the past, solar cells based on CuxS have reached efficiency as high as 10%, but it also suffers serious stability issues. To further improve its efficiency and especially the stability, it is important tounderstand the stability and electronic structure of CuxS. However, due to the complexity of their crystal structures, no systematic theoretical studies have been carried out to understand the stability and electronic structure of the CuxS systems. In this work, using first-principles method, we have systematically studied the crystal and electronic band structures of CuxS (1.25 < x </= 2).For Cu2S, we find that all the three chalcocite phases, i.e., the low-chalcocite, the high-chalcocite, and the cubic-chalcocite phases, have direct bandgaps around 1.3-1.5 eV, with the low-chalcocite being the most stable one. However, Cu vacancies can form spontaneously in these compounds, causing instability of Cu2S. We find that under Cu-rich condition, the anilite Cu1.75S is the most stablestructure. It has a predicted bandgap of 1.4 eV and could be a promising solar cell absorber.
Original languageAmerican English
Number of pages5
StatePublished - 2012
Event2012 IEEE Photovoltaic Specialists Conference - Austin, Texas
Duration: 3 Jun 20128 Jun 2012

Conference

Conference2012 IEEE Photovoltaic Specialists Conference
CityAustin, Texas
Period3/06/128/06/12

NREL Publication Number

  • NREL/CP-5900-54143

Keywords

  • absorbers
  • anilite
  • band structure method
  • chalcocite
  • Cu vacancies
  • CuxS
  • first-principles method
  • PV
  • stability

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