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Ab‐Initio Investigation of the Band Alignment Between Cu 2 ZnSnS 4 and Different Buffer Materials (Al 2 ZnO 4 , CeO 2 , ZnSnO 3 )
Author(s) -
Albar Arwa,
Schwingenschlögl Udo
Publication year - 2019
Publication title -
physica status solidi (rrl) – rapid research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.786
H-Index - 68
eISSN - 1862-6270
pISSN - 1862-6254
DOI - 10.1002/pssr.201800649
Subject(s) - czts , materials science , conduction band , band offset , optoelectronics , ab initio , buffer (optical fiber) , solar cell , band gap , valence band , electron , electrical engineering , chemistry , physics , organic chemistry , engineering , quantum mechanics
Limited efficiency of Cu 2 ZnSnS 4 (CZTS) solar cells due to high recombination rates at the CZTS–buffer interface calls for alternative buffer materials to enhance the open circuit voltage and, therefore, the device performance. By means of ab‐initio hybrid functional calculations, the authors investigate the interfaces between the p ‐type absorber CZTS and the n ‐type buffer materials Al 2 ZnO 4 , CeO 2 , or ZnSnO 3 to evaluate the band alignment. Strong hole confinement is predicted for the CZTS/Al 2 ZnO 4 and CZTS/ZnSnO 3 interfaces. A small conduction band offset of 0.31 eV is obtained for the CZTS/ZnSnO 3 interface, indicating that ZnSnO 3 should be considered for improving the efficiency of CZTS solar cells.