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 language | American English |
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Number of pages | 5 |
State | Published - 2012 |
Event | 2012 IEEE Photovoltaic Specialists Conference - Austin, Texas Duration: 3 Jun 2012 → 8 Jun 2012 |
Conference
Conference | 2012 IEEE Photovoltaic Specialists Conference |
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City | Austin, Texas |
Period | 3/06/12 → 8/06/12 |
NREL Publication Number
- NREL/CP-5900-54143
Keywords
- absorbers
- anilite
- band structure method
- chalcocite
- Cu vacancies
- CuxS
- first-principles method
- PV
- stability