Alleviating non-radiative losses in organic solar cells through side-chain regulation of low-bandgap non-fullerene acceptors

Feng Qi; Qian Li; Hao Lu; Rui Zhang; Shuzhe Liu; Werner Kaminsky; Yaoyao Wei; Qunping Fan; Hongna Zhang; Dangyuan Lei; Francis R. Lin; Zhishan Bo; Alex K.-Y. Jen

doi:10.1038/s41467-025-67351-x

Alleviating non-radiative losses in organic solar cells through side-chain regulation of low-bandgap non-fullerene acceptors

Feng Qi (Co-first Author), Qian Li (Co-first Author), Hao Lu^*, Rui Zhang, Shuzhe Liu, Werner Kaminsky, Yaoyao Wei, Qunping Fan, Hongna Zhang, Dangyuan Lei, Francis R. Lin^*, Zhishan Bo^*, Alex K.-Y. Jen^*

^*Corresponding author for this work

Research output: Journal Publications and Reviews › RGC 21 - Publication in refereed journal › peer-review

Abstract

Non-radiative losses present a significant hurdle limiting the performance of organic solar cells (OSCs). Selenium substitution in non-fullerene acceptors (NFAs) is an effective approach for tuning intermolecular stacking and energy levels in state-of-the-art near-infrared absorbing OSCs. However, the inter-system crossing (ISC) induced by selenium may enhance the formation of triplet excitons in NFAs, aggravating non-radiative losses in OSCs. Herein, we have structurally engineered selenium-containing NFAs through introducing achiral N-alkyl substituents with varied branching sites at C2 or C3 position onto the pyrrole moiety of NFA core. We find that the C2-branched ones in our material system exhibit more intimate molecular packing, improved luminescence efficiency and reduced triplet exciton generation in both neat and blend films, reflected as improved external quantum efficiencies and open-circuit voltages in higher-performance devices. We utilize the best-performing NFA as a ternary component into the benchmark D18:L8-BO absorber to realize a high efficiency of 20.4% (certified as 19.88%). This work shows how precisely regulating the microstructure of NFAs by side-chain modification can reduce the non-radiative losses of OSCs. © The Author(s) 2026.

Original language	English
Article number	712
Number of pages	10
Journal	Nature Communications
Volume	17
Online published	10 Jan 2026
DOIs	https://doi.org/10.1038/s41467-025-67351-x
Publication status	Published - 2026

Funding

F.Q. thanks the support from the National Natural Science Foundation of China (22409108), the Shandong Province Natural Science Foundation of (ZR2024QE324), the Taishan Scholars Program (NO.tsqnz20240815), and the Natural Science Foundation of Qingdao City (24-4-4-zrjj-22-jch). H.L acknowledges the support from the National Natural Science Foundation of China (52403234) and the Shandong Province Natural Science Foundation of (ZR2024QB194). R.Z. thanks the support from the Jiangsu Specially Appointed Professorship (SR21400224), and the Collaborative Innovation Center of Suzhou Nano Science & Technology, the 111 Project, Suzhou Key Laboratory of Surface and Interface of Intelligent Matter (SZS2022011). H.Z. thanks the support from the Shandong Province Natural Science Foundation (2023HWYQ-085) and the Taishan Scholars Program (NO.tsqnz20221137). Z.B. acknowledges the support of the Taishan Scholars Program (NO.tstp20221121). D.L. thanks the financial support from the Research Grants Council of the Hong Kong through a Collaborative Research Equipment Grant (C1015-21EF). A.K.Y.J. thanks the sponsorship of the Lee Shau-Kee Chair Professor (Materials Science), and the support from the APRC Grants (9380086, 9610419, 9610440, 9610492, 9610508) of the City University of Hong Kong, the MHKJFS Grant (MHP/054/23), TCFS grant (GHP/121/22SZ) and MRP Grant (MRP/040/21X) from the Innovation and Technology Commission of Hong Kong, the Green Tech Fund (202020164) from the Environment and Ecology Bureau of Hong Kong, and the GRF grants (11304424, 11307621, 11316422) and CRS grants (CRS_CityU104/23, CRS_HKUST203/23) from the Research Grants Council of Hong Kong. This work was partially financially supported by City University of Hong Kong (9610739) for the project “Fostering Innovation for Resilience and Sustainable Transformation,” officially endorsed by the United Nations Educational, Scientific and Cultural Organization (UNESCO) under the International Decade of Sciences for Sustainable Development (2024–2033).

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

SDG 7 Affordable and Clean Energy

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This full text is made available under CC-BY-NC-ND 4.0. https://creativecommons.org/licenses/by-nc-nd/4.0/

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title = "Alleviating non-radiative losses in organic solar cells through side-chain regulation of low-bandgap non-fullerene acceptors",

abstract = "Non-radiative losses present a significant hurdle limiting the performance of organic solar cells (OSCs). Selenium substitution in non-fullerene acceptors (NFAs) is an effective approach for tuning intermolecular stacking and energy levels in state-of-the-art near-infrared absorbing OSCs. However, the inter-system crossing (ISC) induced by selenium may enhance the formation of triplet excitons in NFAs, aggravating non-radiative losses in OSCs. Herein, we have structurally engineered selenium-containing NFAs through introducing achiral N-alkyl substituents with varied branching sites at C2 or C3 position onto the pyrrole moiety of NFA core. We find that the C2-branched ones in our material system exhibit more intimate molecular packing, improved luminescence efficiency and reduced triplet exciton generation in both neat and blend films, reflected as improved external quantum efficiencies and open-circuit voltages in higher-performance devices. We utilize the best-performing NFA as a ternary component into the benchmark D18:L8-BO absorber to realize a high efficiency of 20.4% (certified as 19.88%). This work shows how precisely regulating the microstructure of NFAs by side-chain modification can reduce the non-radiative losses of OSCs. {\textcopyright} The Author(s) 2026.",

author = "Feng Qi and Qian Li and Hao Lu and Rui Zhang and Shuzhe Liu and Werner Kaminsky and Yaoyao Wei and Qunping Fan and Hongna Zhang and Dangyuan Lei and Lin, {Francis R.} and Zhishan Bo and Jen, {Alex K.-Y.}",

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AU - Qi, Feng

AU - Li, Qian

AU - Lu, Hao

AU - Zhang, Rui

AU - Liu, Shuzhe

AU - Kaminsky, Werner

AU - Wei, Yaoyao

AU - Fan, Qunping

AU - Zhang, Hongna

AU - Lei, Dangyuan

AU - Lin, Francis R.

AU - Bo, Zhishan

AU - Jen, Alex K.-Y.

PY - 2026

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AB - Non-radiative losses present a significant hurdle limiting the performance of organic solar cells (OSCs). Selenium substitution in non-fullerene acceptors (NFAs) is an effective approach for tuning intermolecular stacking and energy levels in state-of-the-art near-infrared absorbing OSCs. However, the inter-system crossing (ISC) induced by selenium may enhance the formation of triplet excitons in NFAs, aggravating non-radiative losses in OSCs. Herein, we have structurally engineered selenium-containing NFAs through introducing achiral N-alkyl substituents with varied branching sites at C2 or C3 position onto the pyrrole moiety of NFA core. We find that the C2-branched ones in our material system exhibit more intimate molecular packing, improved luminescence efficiency and reduced triplet exciton generation in both neat and blend films, reflected as improved external quantum efficiencies and open-circuit voltages in higher-performance devices. We utilize the best-performing NFA as a ternary component into the benchmark D18:L8-BO absorber to realize a high efficiency of 20.4% (certified as 19.88%). This work shows how precisely regulating the microstructure of NFAs by side-chain modification can reduce the non-radiative losses of OSCs. © The Author(s) 2026.

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Alleviating non-radiative losses in organic solar cells through side-chain regulation of low-bandgap non-fullerene acceptors

Abstract

Funding

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GRF: Development of Multifunctional Redox Mediators to Mitigate Halide Segregation in Wide-Bandgap Perovskites for Perovskite Based Tandem Solar Cells

ITF: Development of Commercializable Perovskite-Organic Tandem Solar Cells with High Efficiency and Stability

ITF: Innovative Technology and Critical Materials for Developing Flexible Tandem Solar Cells with Ultra-high Specific Power

Cite this

Alleviating non-radiative losses in organic solar cells through side-chain regulation of low-bandgap non-fullerene acceptors

Abstract

Funding

UN SDGs

Publisher's Copyright Statement

RGC Funding Information

Access Output

Other Access Options

Permanent Link

Other Files and Links

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Projects

GRF: Development of Multifunctional Redox Mediators to Mitigate Halide Segregation in Wide-Bandgap Perovskites for Perovskite Based Tandem Solar Cells

ITF: Development of Commercializable Perovskite-Organic Tandem Solar Cells with High Efficiency and Stability

ITF: Innovative Technology and Critical Materials for Developing Flexible Tandem Solar Cells with Ultra-high Specific Power

Cite this