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- Kumar, Mukesh, et al.
(författare)
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Ternary Cu3BiY3 (Y = S, Se, and Te) for thin-film solar cells
- 2013
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Ingår i: Mater Res Soc Symp Proc. - : Springer Science and Business Media LLC. - 9781605115153 ; , s. 235-240
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Konferensbidrag (refereegranskat)abstract
- Very recently, Cu3BiS3 has been suggested as an alternative material for photovoltaic (PV) thin-film technologies. In this work, we analyze the electronic and optical properties of Cu3BiY 3 with the anion elements Y = S, Se, and Te, employing a first-principles approach within the density function theory. We find that the three Cu2BiY3 compounds have indirect band gaps and the gap energies are in the region of 1.2-1.7 eV. The energy dispersions of the lowest conduction bands are small, and therefore the direct gap energies are only ∼0.1 eV larger than the fundamental gap energies. The flat conduction bands are explained by the presence of localized Bi p-states in the band gap region. Flat energy dispersion implies a large optical absorption, and the calculations reveal that the absorption coefficient of Cu3BiY 3 is larger than 105 cm-1 for photon energies of ∼2.5 eV. The absorption is stronger than other Cu-S based materials like CuInS2 and Cu2ZnSnS4. Thereby, Cu 3BiY3 has the potential to be a suitable material in thin-film PV technologies.
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