Understanding the Role of Organic Hole Transport Layers on Pinhole Blocking and Performance Improvement in Sb 2 Se 3 Solar Cells

Shalvey, Thomas P.; Don, Christopher H.; Bowen, Leon; Veal, Tim D.; Major, Jonathan D.

Abstract

Sb2Se3 is an emerging semiconductor which has shown promise for low‐cost photovoltaic applications. After successive record‐efficiencies using a range of device structures, spiro‐OMeTAD has emerged as the default hole transport material (HTM), however, the function of HTM layers remains poorly understood. Here, thin‐film Sb2Se3 solar cells are fabricated with which three organic HTM layers ‐ namely P3HT, PCDTBT, and spiro‐OMeTAD are investigated. By comparing these against one another, and to a reference device, their role in the device stack are clarified. These organic HTM layers are found to serve a dual purpose, increasing both the average and peak efficiency by simultaneously blocking pinholes and improving the band alignment at the back contact, with marginal differences in performance between the different HTMs. This produced a champion device of 7.44% using P3HT, resulting from an improvement in all performance parameters. A more complex processing route, run‐to‐run variability, and lower overall device performance compared to the other organics challenge the assumption that spiro‐OMeTAD is the optimal HTM for Sb2Se3 devices. A Schottky barrier at the Au‐Sb2Se3 contact despite the deep work function of gold implies Fermi level pinning due to a defective interface, which each of the organic HTMs are equally capable of alleviating.

Citation

Shalvey, T. P., Don, C. H., Bowen, L., Veal, T. D., & Major, J. D. (online). Understanding the Role of Organic Hole Transport Layers on Pinhole Blocking and Performance Improvement in Sb 2 Se 3 Solar Cells. Advanced Materials Interfaces, Article 2400394. https://doi.org/10.1002/admi.202400394

• Journal Article Type: Article
• Acceptance Date: Sep 21, 2024
• Online Publication Date: Oct 19, 2024
• Deposit Date: Oct 30, 2024
• Publicly Available Date: Oct 30, 2024
• Journal: Advanced Materials Interfaces
• Electronic ISSN: 2196-7350
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Article Number: 2400394
• DOI: https://doi.org/10.1002/admi.202400394
• Keywords: back contact, pinhole blocking, hole transport, organic, Sb2Se3, uniformity, Schottky barrier
• Public URL: https://durham-repository.worktribe.com/output/2983954