Impact of a RbF Postdeposition Treatment on the Electronic Structure of the CdS/Cu(In,Ga)Se2 Heterojunction in High-Efficiency Thin-Film Solar Cells
ACS Energy Letters
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Recently, a world-record efficiency of 22.6% was achieved by applying a RbF postdeposition treatment (PDT) on a Cu(In,Ga)Se2 (CIGSe) thin-film solar cell absorber surface. Here, we study the impact of this RbF-PDT on the electronic structure of the CIGSe surface and the CdS/CIGSe interface using ultraviolet and X-ray photoelectron spectroscopy (UPS and XPS), as well as inverse photoemission spectroscopy (IPES). After RbF-PDT, we find a small downward shift of the band edges, while the surface band gap value itself is not affected. In addition, a further downward band bending in the CIGSe absorber is observed upon formation of the RbF-PDT CdS/CIGSe interface. We derive a flat conduction band alignment between the RbF-PDT CIGSe absorber and the CdS buffer, commensurate with the high efficiencies of solar cell devices prepared with RbF-PDT. © 2017 American Chemical Society.
Kreikemeyer Lorenzo, D.,
Friedlmeier, T. M.,
Impact of a RbF Postdeposition Treatment on the Electronic Structure of the CdS/Cu(In,Ga)Se2 Heterojunction in High-Efficiency Thin-Film Solar Cells.
ACS Energy Letters, 2(10),