Self-assembled molecules for hole-selective electrodes in highly stable and efficient inverted perovskite solar cells with ultralow energy loss

Li, W., Cariello, M. , Méndez, M., Cooke, G. and Palomares, E. (2023) Self-assembled molecules for hole-selective electrodes in highly stable and efficient inverted perovskite solar cells with ultralow energy loss. ACS Applied Energy Materials, 6(3), pp. 1239-1247. (doi: 10.1021/acsaem.2c02880) (PMID:36817750) (PMCID:PMC9930087)

Abstract

Good selective contacts are necessary for solar cells that are efficient and have long-term stability. Since 1998, with the advent of solid-state dye sensitized solar cells (DSSC), Spiro-OMeTAD has become the reference hole-transporting material. Yet, for efficient solar cells Spiro-OMeTAD must be partially oxidized with chemical dopants, which compromises the long-term stability of the solar cell. Alternatively, semiconductor polymers such as PTAA have been also studied, matching or improving the solar cell characteristics. However, PTAA-based devices lack long-term stability. Moreover, both Spiro-OMeTAD and PTAA are expensive materials to synthesize. Hence, approaches toward increasing the solar cell stability without compromising the device efficiency and decreasing the manufacturing cost are very desirable. In this work we have modified Spiro-OMeTAD, by an easy-to-use methodology, by introducing a carboxylic acid anchoring group (Spiro-Acid), thereby allowing the formation of self-assembled monolayers (SAMs) of the hole-transporting material in dopant-free p–i–n hybrid perovskite solar cells (iPSCs). The resulting device showed a champion efficiency of 18.15% with ultralow energy loss, which is the highest efficiency among Spiro-OMeTAD-based iPSCs, and a remarkable fill factor of over 82%, as well as excellent long-term illumination stability. Charge transfer and charge carrier dynamics are studied by using advanced transient techniques to understand the interfacial kinetics. Our results demonstrate that the Spiro-OMeTAD-based SAMs have a great potential in producing low-cost iPSC devices, due to lower material usage, good long-term stability, and high performance.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Cooke, Professor Graeme and Cariello, Dr Michele
• Authors: Li, W., Cariello, M., Méndez, M., Cooke, G., and Palomares, E.
• College/School: College of Science and Engineering > School of Chemistry
• Journal Name: ACS Applied Energy Materials
• Publisher: American Chemical Society
• ISSN: 2574-0962
• ISSN (Online): 2574-0962
• Published Online: 13 January 2023
• Copyright Holders: Copyright © 2023 The Authors
• First Published: First published in ACS Applied Energy Materials 6(3): 1239-1247
• Publisher Policy: Reproduced under a Creative Commons License

Project Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
141731		Physical organic chemistry - opportunities in synthesis, materials and pharmaceuticals	Graeme Cooke	Engineering and Physical Sciences Research Council (EPSRC)	EP/E036244/1	Chemistry