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Natural band alignments and band offsets of Sb2Se3 solar cells

DOI: 10.1021/acsaem.0c01477 DOI Help

Authors: Huw Shiel (University of Liverpool) , Oliver S. Hutter (University of Liverpool; Northumbria University) , Laurie J. Phillips (University of Liverpool) , Jack E. N. Swallow (University of Liverpool) , Leanne A. H. Jones (University of Liverpool) , Thomas J. Featherstone (University of Liverpool) , Matthew J. Smiles (University of Liverpool) , Pardeep K. Thakur (Diamond Light Source) , Tien-lin Lee (Diamond Light Source) , Vinod R. Dhanak (University of Liverpool) , Jonathan D. Major (University of Liverpool) , Tim D. Veal (University of Liverpool)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Acs Applied Energy Materials

State: Published (Approved)
Published: December 2020
Diamond Proposal Number(s): 23160

Abstract: Sb2Se3 is a promising material for use in photovoltaics, but the optimum device structure has not yet been identified. This study provides band alignment measurements between Sb2Se3, identical to that used in high-efficiency photovoltaic devices, and its two most commonly used window layers, namely, CdS and TiO2. Band alignments are measured via two different approaches: Anderson’s rule was used to predict an interface band alignment from measured natural band alignments, and the Kraut method was used in conjunction with hard X-ray photoemission spectroscopy to directly measure the band offsets at the interface. This allows examination of the effect of interface formation on the band alignments. The conduction band minimum (CBM) of TiO2 is found by the Kraut method to lie 0.82 eV below that of Sb2Se3, whereas the CdS CBM is only 0.01 eV below that of Sb2Se3. Furthermore, a significant difference is observed between the natural alignment- and Kraut method-determined offsets for TiO2/Sb2Se3, whereas there is little difference for CdS/Sb2Se3. Finally, these results are related to device performance, taking into consideration how these results may guide the future development of Sb2Se3 solar cells and providing a methodology that can be used to assess band alignments in device-relevant systems.

Journal Keywords: Sb2Se3; band alignments; window layer; photovoltaics; photoemission; HAXPES

Subject Areas: Materials, Chemistry, Energy

Instruments: I09-Surface and Interface Structural Analysis