Reactive DC Sputtered TiO 2 Electron Transport Layers for Cadmium‐Free Sb 2 Se 3 Solar Cells

Don, Christopher H.; Shalvey, Thomas P.; Sindi, Daniya A.; Lewis, Bradley; Swallow, Jack E. N.; Bowen, Leon; Fernandes, Daniel F.; Kubart, Tomas; Biswas, Deepnarayan; Thakur, Pardeep K.; Lee, Tien‐Lin; Major, Jonathan D.

Abstract

The evolution of Sb2Se3 heterojunction devices away from CdS electron transport layers (ETL) to wide bandgap metal oxide alternatives is a critical target in the development of this emerging photovoltaic material. Metal oxide ETL/Sb2Se3 device performance has historically been limited by relatively low fill factors, despite offering clear advantages with regards to photocurrent collection. In this study, TiO2 ETLs are fabricated via direct current reactive sputtering and tested in complete Sb2Se3 devices. A strong correlation between TiO2 ETL processing conditions and the Sb2Se3 solar cell device response under forward bias conditions is observed and optimized. Numerical device models support experimental evidence of a spike‐like conduction band offset, which can be mediated, provided a sufficiently high conductivity and low interfacial defect density can be achieved in the TiO2 ETL. Ultimately, a SnO2:F/TiO2/Sb2Se3/P3HT/Au device with the reactively sputtered TiO2 ETL delivers an 8.12% power conversion efficiency (η), the highest TiO2/Sb2Se3 device reported to‐date. This is achieved by a substantial reduction in series resistance, driven by improved crystallinity of the reactively sputtered anatase‐TiO2 ETL, whilst maintaining almost maximum current collection for this device architecture.

Citation

Don, C. H., Shalvey, T. P., Sindi, D. A., Lewis, B., Swallow, J. E. N., Bowen, L., Fernandes, D. F., Kubart, T., Biswas, D., Thakur, P. K., Lee, T., & Major, J. D. (2024). Reactive DC Sputtered TiO 2 Electron Transport Layers for Cadmium‐Free Sb 2 Se 3 Solar Cells. Advanced Energy Materials, 14(34), Article 2401077. https://doi.org/10.1002/aenm.202401077

• Journal Article Type: Article
• Acceptance Date: May 1, 2024
• Online Publication Date: Jun 11, 2024
• Publication Date: Sep 13, 2024
• Deposit Date: Jun 18, 2024
• Publicly Available Date: Jun 18, 2024
• Journal: Advanced Energy Materials
• Print ISSN: 1614-6832
• Electronic ISSN: 1614-6840
• Publisher: Wiley-VCH Verlag
• Peer Reviewed: Peer Reviewed
• Volume: 14
• Issue: 34
• Article Number: 2401077
• DOI: https://doi.org/10.1002/aenm.202401077
• Keywords: sputtering, antimony, selenide, Sb2Se3, photovoltaics, TiO2, solar
• Public URL: https://durham-repository.worktribe.com/output/2483999
• Additional Information: Estimated acceptance date