High open-circuit voltage in transition metal dichalcogenide solar cells

Svatek, Simon A.; Bueno-Blanco, Carlos; Lin, Der-Yuh; Kerfoot, James; Mac�as, Carlos; Zehender, Marius H.; Tob�as, Ignacio; Garc�a-Linares, Pablo; Taniguchi, Takashi; Watanabe, Kenji; Beton, Peter; Antol�n, Elisa

Abstract

The conversion efficiency of ultra-thin solar cells based on layered materials has been limited by their open-circuit voltage, which is typically pinned to a value under 0.6 V. Here we report an open-circuit voltage of 1.02 V in a 120 nm-thick vertically stacked homojunction fabricated with substitutionally doped MoS2. This high open-circuit voltage is consistent with the band alignment in the MoS2 homojunction, which is more favourable than in widely-used TMDC heterostructures. It is also attributed to the high performance of the substitutionally doped MoS2, in particular the p-type material doped with Nb, which is demonstrated by the observation of electroluminescence from tunnelling graphene/BN/MoS2 structures in spite of the indirect nature of bulk MoS2. We find that illuminating the TMDC/metal contacts decreases the measured open-circuit voltage in MoS2 van der Waals homojunctions because they are photoactive, which points to the need of developing low-resistance, ohmic contacts to doped MoS2 in order to achieve high efficiency in practical devices. The high open-circuit voltage demonstrated here confirms the potential of layered transition-metal dichalcogenides for the development of highly efficient, ultra-thin solar cells.

Citation

Svatek, S. A., Bueno-Blanco, C., Lin, D.-Y., Kerfoot, J., Macías, C., Zehender, M. H., …Antolín, E. (2021). High open-circuit voltage in transition metal dichalcogenide solar cells. Nano Energy, 79, Article 105427. https://doi.org/10.1016/j.nanoen.2020.105427

• Journal Article Type: Article
• Acceptance Date: Sep 17, 2020
• Online Publication Date: Sep 25, 2020
• Publication Date: Jan 1, 2021
• Deposit Date: Oct 23, 2020
• Publicly Available Date: Sep 26, 2021
• Journal: Nano Energy
• Print ISSN: 2211-2855
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 79
• Article Number: 105427
• DOI: https://doi.org/10.1016/j.nanoen.2020.105427
• Keywords: Renewable Energy, Sustainability and the Environment; Electrical and Electronic Engineering; General Materials Science
• Public URL: https://nottingham-repository.worktribe.com/output/4986231
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S221128552031003X