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High-Efficiency WSe2 Photovoltaic Devices with Electron-Selective Contacts
Kwan-Ho Kim1,2, Maksim Andreev1, Soodon Choi1
1Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon 16419, Korea.
ACS Nano
|April 18, 2022
Summary
Researchers developed a new vertical tungsten diselenide (WSe2) photovoltaic device achieving a 5.44% power conversion efficiency. This breakthrough overcomes previous limitations in van der Waals materials for solar energy applications.
Area of Science:
- Materials Science
- Renewable Energy
- Semiconductor Physics
Background:
- Growing global energy demand necessitates advanced renewable energy solutions.
- Van der Waals materials show promise for thin, efficient photovoltaic (PV) devices.
- Achieving high power conversion efficiencies (PCEs) above 5% in these PV devices remains a challenge.
Purpose of the Study:
- To demonstrate a vertical WSe2 PV device with enhanced PCE.
- To investigate the role of a tungsten oxide layer in improving PV performance.
- To overcome Fermi-level pinning limitations at WSe2 interfaces.
Main Methods:
- Fabrication of a vertical WSe2 PV device.
- Integration of a tungsten oxide layer and monolayer graphene as an electron-selective contact.
- Development of an optimized bottom contact scheme.
- Performance testing under one-sun AM1.5G illumination.
Main Results:
- Achieved a high PCE of 5.44% in the vertical WSe2 PV device.
- The tungsten oxide layer enhanced the internal electric field and acted as an electron-selective contact.
- Contact engineering significantly improved the PCE by over five times compared to previous benchmarks.
Conclusions:
- The developed vertical WSe2 PV device represents a significant advancement in van der Waals photovoltaics.
- Tungsten oxide and graphene heterostructures offer a promising strategy for efficient electron extraction.
- This contact engineering approach provides a simple yet effective pathway to high-performance, thin-film solar cells.
