Organic Solar Cells with 20.12% Efficiency Enabled by Monosubstituted Carbazole-Based Self-Assembled Monolayers
Journal article, 2025
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, CF3) on indium tin oxide (ITO) and their device performance. Fluorine substitution achieves the highest surface coverage but poor interfacial order, while bulky 1CF3-2PACz 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.
Author
Qiaonan Chen
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Jingnan Wu
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Maureen Gumbo
Chemistry and Biochemistry Phd Students and Postdocs
Leandro Rezende Franco
Applied Chemistry 8.2
Karlstad University
Kangbo Sun
Shenzhen Technology University
Lunjie Zeng
Chalmers, Physics, Nano and Biophysics
X. J. Liu
Linköping University
Yufei Wang
Shenzhen Technology University
Donghong Yu
Aalborg University
Zhengzhou University
Sino-Danish Center for Education and Research Denmark
Lars Öhrström
Chalmers, Chemistry and Chemical Engineering
Mailde S. Ozório
University of Copenhagen
Alexandre Holmes
Applied Chemistry 8.2
C. Moyses Araujo
Uppsala University
Karlstad University
Eva Olsson
Chalmers, Physics, Nano and Biophysics
M. Fahlman
Linköping University
Renqiang Yang
Jianghan University
Ergang Wang
Zhengzhou University
Chalmers, Chemistry and Chemical Engineering
ACS Energy Letters
23808195 (eISSN)
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Swedish Foundation for Strategic Research (SSF) (RIF21-0026), 2022-09-01 -- 2027-12-31.
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Subject Categories (SSIF 2025)
Materials Chemistry
Condensed Matter Physics
Physical Chemistry
DOI
10.1021/acsenergylett.5c02585