Improved performance of Cd-free CZTS thin-film solar cells by using CZTS0.4Se0.6 BSF layer

Cu2ZnSnS4 (CZTS) thin film solar cells (TFSCs) have received great attention from the solar cell industry for their environment, price, high absorption coefficient and great electronic properties. This work provides a strategy to prompt the photoelectric conversion efficiency (η) of CdS/CZTS-based T...

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Bibliographic Details
Published in:Journal of physics. Conference series 2023-02, Vol.2418 (1), p.012002
Main Authors: Zhang, Wenchao, You, Chengwu, Dan, Zhiying, Wang, Weizhe, Dong, Ruibing
Format: Article
Language:English
Subjects:
Absorptivity
Buffer layers
Conduction bands
Copper zinc tin sulfide
Energy conversion efficiency
Photoelectricity
Photovoltaic cells
Physics
Selenium
Semiconductor materials
Solar cells
Thin films
Titanium dioxide
Wide bandgap semiconductors
Zinc sulfide
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Summary:Cu2ZnSnS4 (CZTS) thin film solar cells (TFSCs) have received great attention from the solar cell industry for their environment, price, high absorption coefficient and great electronic properties. This work provides a strategy to prompt the photoelectric conversion efficiency (η) of CdS/CZTS-based TFSCs via introducing the back surface field (BSF) layer and wxAMPS to simulate the results. Meanwhile, the optimum ratio of sulfur to selenium in the BSF layer material CZTSSe has been also studied, and a new device structure has been constructed. Beneficial from the introduction of CZTSSe as a BSF layer, the interface recombination is suppressed and leads to an enhanced Voc. Subsequently, MoO3, ZnS, WO3, TiO2 and In2S3 as candidates to substitute for the toxic Cd buffer layer are investigated. The results demonstrate that In2S3/CZTSSe exhibits the best performance with 28.59 % and 0.99 V, ascribed to a superior spike-like value. It was found that the presence of a spike-like conduction band (CB) at the In2S3/CZTSSe interface and a more suitable conduction band offset (CBO) value could suppress the interfacial complexation. Therefore, In2S3 performs best as a buffer layer material. However, due to the cost of indium, this paper recommends the utilization of wide bandgap semiconductor materials MoO3 and ZnS, which also have good stability and conversion efficiencies that can reach 28.38% and 28.41%, respectively. The work of this paper provides important guidance for researchers to manufacture CZTS TFSCs.
ISSN:1742-6588
1742-6596
DOI:10.1088/1742-6596/2418/1/012002