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Theoretical study on the Cs/Cs-O adsorbed graphene/semiconductor heterojunction anode for thermionic converters

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Abstract

Graphene/semiconductor heterojunction anodes can significantly enhance the output voltage by the photovoltaic effect. However, a significant challenge arises from the high intrinsic work function of heterojunction surfaces, which limits efficient electron emission. In this study, we explored the potential of low work function materials modified by Cs/Cs-O adsorption as anodes for thermionic (TI) converters through first principles calculations. The results demonstrate that the work functions of the graphene/MoS2 and the graphene/n-type Si surfaces with only Cs coating can decrease to 1.48 eV and 2.46 eV, respectively. The multiple Cs-O atoms co-adsorption enhances the dipole moment, resulting in a further reduction of the work function of the graphene/MoS2 surface to 1.25 eV. In addition, the impact of work function on the performance of TI converters is revealed by using concentrated solar energy as heat source. The highest conversion efficiency achieves 15.25% for the Cs-4O: Gr/MoS2 anode. This study establishes a robust foundation for further advancement of the TI converters with graphene/semiconductor heterojunction anodes.

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The data that support the findings of this study are available from the corresponding author, Gang Xiao, upon reasonable request.

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Funding

This work was supported by the National Natural Science Foundation of China (No. 52325605), the Zhejiang Provincial Natural Science Foundation (No. LR20E060001) and the Fundamental Research Funds for the Central Universities (No. 2022ZFJH004).

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Authors and Affiliations

  1. Key Laboratory of Clean Energy and Carbon Neutrality of Zhejiang Province, Zhejiang University, Hangzhou, 310027, Zhejiang, China

    Weiting Sun, Haoran Xu, Hao Qiu & Gang Xiao

  2. State Key Laboratory of Clean Energy Utilization, Zhejiang University, 38 Zheda Road, Hangzhou, 310027, Zhejiang, China

    Weiting Sun, Haoran Xu, Hao Qiu & Gang Xiao

  3. School of Energy and Power Engineering, Shandong University, Jinan, 250061, Shandong, China

    Hao Qiu

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  1. Weiting Sun
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  2. Haoran Xu
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  4. Gang Xiao
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Contributions

All authors contributed to the study conception and design. Weiting Sun: Conceptualization, Methodology, Investigation, Software, Validation, Formal analysis, Visualization, Data curation, Writing-original draft, Writing-review & editing. Haoran Xu: Writing-review & editing. Hao Qiu: Writing-review & editing. Gang Xiao: Supervision, Funding acquisition, Project administration.

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Correspondence to Gang Xiao.

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Sun, W., Xu, H., Qiu, H. et al. Theoretical study on the Cs/Cs-O adsorbed graphene/semiconductor heterojunction anode for thermionic converters. Waste Dispos. Sustain. Energy (2024). https://doi.org/10.1007/s42768-024-00191-5

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