Organic Solar Cells with 20.12% Efficiency Enabled by Monosubstituted Carbazole-Based Self-Assembled Monolayers
Carbazole-derived self-assembled monolayer (SAM) materials as hole transport layers are widely used in organic photovoltaics, yet the role of subtle substituent effects on interfacial structure and device performance remains underexplored. Here, we systematically investigate monosubstituted carbazole SAMs (1X-2PACz, X = F, Cl, Br, I, CF<inf>3</inf>) on indium tin oxide (ITO) and their device performance. Fluorine substitution achieves the highest surface coverage but poor interfacial order, while bulky 1CF<inf>3</inf>-2PACz introduces interfacial disorder. In contrast, Cl-, Br-, and I-substituted SAMs exhibit favorable packing and work-function alignment, enabling efficiencies of up to 19.03% in PM6:L8-BO and 20.12% in D18:L8-BO based solar cells. Crucially, cross-sectional scanning transmission electron microscopy provides the first direct visualization of the nonideal SAM morphologies on ITO, revealing molecular aggregates in ITO valleys, mono- or multilayers on flat regions, and incomplete surface coverage. These findings establish how substituents and processing critically govern interfacial packing and photovoltaic efficiency, guiding SAM-based interfacial design.
Authors
- C. Moysés Araújo (ORCID: https://orcid.org/0000-0001-5192-0016)
- Kangbo Sun (ORCID: https://orcid.org/0000-0002-6223-6751)
- Leandro R. Franco (ORCID: https://orcid.org/0000-0002-8692-3396)
- Maureen Gumbo (ORCID: https://orcid.org/0000-0001-7018-4595)
- Eva Olsson (ORCID: https://orcid.org/0000-0002-3791-9569)
- Ergang Wang (ORCID: https://orcid.org/0000-0002-4942-3771)
- Alexandre Holmes (ORCID: https://orcid.org/0009-0003-1340-4602)
- Mailde S. Ozório (ORCID: https://orcid.org/0000-0003-3966-8908)
- Lars Öhrström (ORCID: https://orcid.org/0000-0002-6420-2141)
- Donghong Yu (ORCID: https://orcid.org/0000-0002-3035-5035)
- Xianjie Liu (ORCID: https://orcid.org/0000-0002-3190-2774)
- Mats Fahlman (ORCID: https://orcid.org/0000-0001-9879-3915)
- Qiaonan Chen (ORCID: https://orcid.org/0000-0002-1788-9454)
- Lunjie Zeng (ORCID: https://orcid.org/0000-0002-4564-7217)
- Yufei Wang (ORCID: https://orcid.org/0000-0002-1960-3413)
- Jingnan Wu (ORCID: https://orcid.org/0000-0002-9868-3721)
- Renqiang Yang
Institutions
- Linköping University (SE)
- Uppsala University (SE)
- University of Copenhagen (DK)
- Jianghan University (CN)
- Zhengzhou University (CN)
- Integrated Optoelectronics (Norway) (NO)
- Sino-Danish Centre for Education and Research (CN)
- Department of Science and Technology and Biotechnology (IN)
- Astronomy and Space (AU)
- Shenzhen Technology University (CN)
- Karlstad University (SE)
- Chalmers University of Technology (SE)
- Aalborg University (DK)
Publication Details
- Journal
- ACS Energy Letters
- Published
- 2025-10-21
- DOI
- https://doi.org/10.1021/acsenergylett.5c02585
- Citations
- 4
- Primary Topic
- Organic Electronics and Photovoltaics
- Type
- article
- Field-Weighted Citation Impact
- 2.92
Funders
- National Research Foundation
- Stiftelsen för Strategisk Forskning
- Danmarks Grundforskningsfond
- National Natural Science Foundation of China
- Svenska Forskningsrådet Formas
- National Science Council
- Vetenskapsrådet
- Sino-Danish Center
- Basic and Applied Basic Research Foundation of Guangdong Province