Premium
Enhancing the Hydrogen Evolution Properties of Kesterite Absorber by Si‐Doping in the Surface of CZTS Thin Film
Author(s) -
Vishwakarma Manoj,
Kumar Mukesh,
Hendrickx Mylène,
Hadermann Joke,
Singh Aadesh P.,
Batra Yogita,
Mehta B. R.
Publication year - 2021
Publication title -
advanced materials interfaces
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.671
H-Index - 65
ISSN - 2196-7350
DOI - 10.1002/admi.202002124
Subject(s) - czts , kesterite , materials science , photocurrent , doping , thin film , band bending , band gap , semiconductor , fermi level , grain boundary , analytical chemistry (journal) , optoelectronics , nanotechnology , electron , metallurgy , microstructure , physics , chemistry , chromatography , quantum mechanics
In this work, the effects of Si‐doping in Cu 2 ZnSnS 4 are examined computationally and experimentally. The density functional theory calculations show that an increasing concentration of Si (from x = 0 to x = 1) yields a band gap rise due to shifting of the conduction band minimum towards higher energy states in the Cu 2 Zn(Sn 1− x Si x )S 4 . CZTSiS thin film prepared by co‐sputtering process shows Cu 2 Zn(Sn 1− x Si x )S 4 (Si‐rich) and Cu 2 ZnSnS 4 (S‐rich) kesterite phases on the surface and in the bulk of the sample, respectively. A significant change in surface electronic properties is observed in CZTSiS thin film. Si‐doping in CZTS inverts the band bending at grain‐boundaries from downward to upward and the Fermi level of CZTSiS shifts upward. Further, the coating of the CdS and ZnO layer improves the photocurrent to ≈ 5.57 mA cm −2 at − 0.41 V RHE in the CZTSiS/CdS/ZnO sample, which is 2.39 times higher than that of pure CZTS. The flat band potential increases from CZTS ≈ 0.43 V RHE to CZTSiS/CdS/ZnO ≈ 1.31 V RHE indicating the faster carrier separation process at the electrode–electrolyte interface in the latter sample. CdS/ZnO layers over CZTSiS significantly reduce the charge transfer resistance at the semiconductor–electrolyte interface.