Recycling of spin-triplet excitons in organic photovoltaics

Qian Li; Lingchen Kong; Le Mei; Shanchao Ouyang; Yiwen Ji; Baobing Fan; Huanhuan Gao; Wei Gao; Feng Qi; Zhiqiang Guan; Nan Zhang; Hin-Lap Yip; Chun-Sing Lee; Dangyuan Lei; Chunfeng Zhang; Sai-Wing Tsang; Xian-Kai Chen; Francis R. Lin; Alex K.-Y. Jen

doi:10.1038/s41586-026-10419-5

Recycling of spin-triplet excitons in organic photovoltaics

Qian Li (Co-first Author)
, Lingchen Kong (Co-first Author)
, Le Mei (Co-first Author)
, Shanchao Ouyang
, Yiwen Ji
, Baobing Fan
, Huanhuan Gao
, Wei Gao
, Feng Qi
, Zhiqiang Guan
, Nan Zhang
, Hin-Lap Yip
, Chun-Sing Lee
, Dangyuan Lei
, Chunfeng Zhang
, Sai-Wing Tsang
, Xian-Kai Chen^*
, Francis R. Lin^*
, Alex K.-Y. Jen^*

^*Corresponding author for this work

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

4 Citations (Scopus)

Abstract

Non-geminate recombination in organic photovoltaics (OPVs) forms low-energy spin-triplet excitons (T₁) that are known to result in irreversible, non-radiative relaxations^{1, 2, 3, 4–5}. Here we experimentally show in an OPV system incorporating a non-fullerene acceptor with a narrowed singlet–triplet gap that T₁ excitons can be redissociated through the interfacial charge-transfer state to form free carriers. We corroborate this by identifying the increased population of free carriers following triplet sensitization of the acceptor in an OPV blend, and illustrate the way in which this mechanism alters the evolution of T₁ and free carrier populations. We reveal how the distribution of orbitals in the molecule and exciton delocalization in aggregates affect the singlet–triplet energetics of the acceptor in the condensed phase, rendering the traffic between T₁ and the spin-triplet charge-transfer state controllable. By introducing this acceptor as a ternary component into other host OPV systems, we manage to recover the triplet-mediated losses and improve OPV efficiencies by maximizing the number of extractable photocarriers. This study deepens our understanding of the fundamentals of OPVs, and shows how to develop future organic optoelectronics by demonstratating the recovery of low-energy T₁ excitons into usable charges for electricity or light generation instead of heat. © The Author(s), under exclusive licence to Springer Nature Limited 2026.

Original language	English
Pages (from-to)	1204-1210
Journal	Nature
Volume	652
Issue number	8112
Online published	29 Apr 2026
DOIs	https://doi.org/10.1038/s41586-026-10419-5
Publication status	Published - 30 Apr 2026

Funding

A.K.Y.J. is grateful for sponsorship by the Lee Shau-Kee Chair Professorship in Materials Science, and support from APRC grants (grant nos. 9380086, 9610419, 9610440, 9610492, 9610508) of the City University of Hong Kong; MHKJFS, TCFS and MRP (grant nos. MHP/054/23, GHP/121/22SZ, MRP/040/21X, respectively) grants from the Innovation and Technology Commission of Hong Kong; and GRF (grant nos. 11307621, 11316422, 11308625) and CRS (grant nos. CRS_CityU104/23 and CRS_HKUST203/23) grants from the Research Grants Council of Hong Kong. This work was partially financially supported by City University of Hong Kong (grant no. 9610739) via the ‘Fostering Innovation for Resilience and Sustainable Transformation’ project, which is officially endorsed by the United Nations Educational, Scientific and Cultural Organization, under the International Decade of Sciences for Sustainable Development (2024–2033). D.L. is grateful for support from the Collaborative Research Equipment Grant (grant no. C1015-21EF) via the Research Grants Council of Hong Kong. C.S.L. is grateful for support from the General Research Fund from the Research Grants Council of the Hong Kong Special Administrative Region (grant no. CityU 11303923). S.W.T. is grateful for the support from the National Natural Science Foundation of China (grant no. 62474151). X.K.C. gratefully acknowledges financial support from the National Key Research and Development Program of China (grant no. 2022YFB4200600), the National Natural Science Foundation of China (grant nos. W2511063 and 52473190), the Natural Science Foundation of Jiangsu Province (grant no. BK20240042), the Science and Technology Project of Suzhou (grant no. ZXL2024394), the Suzhou Key Laboratory of Functional Nano and Soft Materials, Collaborative Innovation Center of Suzhou Nano Science and Technology, and the 111 Project. We also gratefully acknowledge Y. Li, Y. Wang, Z. Yue and T. Xia from the City University of Hong Kong for their assistance with ultraviolet photoelectron spectroscopy, photoluminescence and electroluminescence measurements, and cell characterizations; M. Yan from the Nanjing University for their assistance with spectroscopic measurements; R. Walia from the Soochow University for their assistance with theoretical calculations; and S.-H. Jang from the University of Washington for their assistance with writing the manuscript.

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title = "Recycling of spin-triplet excitons in organic photovoltaics",

abstract = "Non-geminate recombination in organic photovoltaics (OPVs) forms low-energy spin-triplet excitons (T1) that are known to result in irreversible, non-radiative relaxations1, 2, 3, 4–5. Here we experimentally show in an OPV system incorporating a non-fullerene acceptor with a narrowed singlet–triplet gap that T1 excitons can be redissociated through the interfacial charge-transfer state to form free carriers. We corroborate this by identifying the increased population of free carriers following triplet sensitization of the acceptor in an OPV blend, and illustrate the way in which this mechanism alters the evolution of T1 and free carrier populations. We reveal how the distribution of orbitals in the molecule and exciton delocalization in aggregates affect the singlet–triplet energetics of the acceptor in the condensed phase, rendering the traffic between T1 and the spin-triplet charge-transfer state controllable. By introducing this acceptor as a ternary component into other host OPV systems, we manage to recover the triplet-mediated losses and improve OPV efficiencies by maximizing the number of extractable photocarriers. This study deepens our understanding of the fundamentals of OPVs, and shows how to develop future organic optoelectronics by demonstratating the recovery of low-energy T1 excitons into usable charges for electricity or light generation instead of heat. {\textcopyright} The Author(s), under exclusive licence to Springer Nature Limited 2026.",

author = "Qian Li and Lingchen Kong and Le Mei and Shanchao Ouyang and Yiwen Ji and Baobing Fan and Huanhuan Gao and Wei Gao and Feng Qi and Zhiqiang Guan and Nan Zhang and Hin-Lap Yip and Chun-Sing Lee and Dangyuan Lei and Chunfeng Zhang and Sai-Wing Tsang and Xian-Kai Chen and Lin, \{Francis R.\} and Jen, \{Alex K.-Y.\}",

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AU - Li, Qian

AU - Kong, Lingchen

AU - Mei, Le

AU - Ouyang, Shanchao

AU - Ji, Yiwen

AU - Fan, Baobing

AU - Gao, Huanhuan

AU - Gao, Wei

AU - Qi, Feng

AU - Guan, Zhiqiang

AU - Zhang, Nan

AU - Yip, Hin-Lap

AU - Lee, Chun-Sing

AU - Lei, Dangyuan

AU - Zhang, Chunfeng

AU - Tsang, Sai-Wing

AU - Chen, Xian-Kai

AU - Lin, Francis R.

AU - Jen, Alex K.-Y.

PY - 2026/4/30

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N2 - Non-geminate recombination in organic photovoltaics (OPVs) forms low-energy spin-triplet excitons (T1) that are known to result in irreversible, non-radiative relaxations1, 2, 3, 4–5. Here we experimentally show in an OPV system incorporating a non-fullerene acceptor with a narrowed singlet–triplet gap that T1 excitons can be redissociated through the interfacial charge-transfer state to form free carriers. We corroborate this by identifying the increased population of free carriers following triplet sensitization of the acceptor in an OPV blend, and illustrate the way in which this mechanism alters the evolution of T1 and free carrier populations. We reveal how the distribution of orbitals in the molecule and exciton delocalization in aggregates affect the singlet–triplet energetics of the acceptor in the condensed phase, rendering the traffic between T1 and the spin-triplet charge-transfer state controllable. By introducing this acceptor as a ternary component into other host OPV systems, we manage to recover the triplet-mediated losses and improve OPV efficiencies by maximizing the number of extractable photocarriers. This study deepens our understanding of the fundamentals of OPVs, and shows how to develop future organic optoelectronics by demonstratating the recovery of low-energy T1 excitons into usable charges for electricity or light generation instead of heat. © The Author(s), under exclusive licence to Springer Nature Limited 2026.

AB - Non-geminate recombination in organic photovoltaics (OPVs) forms low-energy spin-triplet excitons (T1) that are known to result in irreversible, non-radiative relaxations1, 2, 3, 4–5. Here we experimentally show in an OPV system incorporating a non-fullerene acceptor with a narrowed singlet–triplet gap that T1 excitons can be redissociated through the interfacial charge-transfer state to form free carriers. We corroborate this by identifying the increased population of free carriers following triplet sensitization of the acceptor in an OPV blend, and illustrate the way in which this mechanism alters the evolution of T1 and free carrier populations. We reveal how the distribution of orbitals in the molecule and exciton delocalization in aggregates affect the singlet–triplet energetics of the acceptor in the condensed phase, rendering the traffic between T1 and the spin-triplet charge-transfer state controllable. By introducing this acceptor as a ternary component into other host OPV systems, we manage to recover the triplet-mediated losses and improve OPV efficiencies by maximizing the number of extractable photocarriers. This study deepens our understanding of the fundamentals of OPVs, and shows how to develop future organic optoelectronics by demonstratating the recovery of low-energy T1 excitons into usable charges for electricity or light generation instead of heat. © The Author(s), under exclusive licence to Springer Nature Limited 2026.

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SN - 0028-0836

VL - 652

SP - 1204

EP - 1210

JO - Nature

JF - Nature

IS - 8112

ER -

Recycling of spin-triplet excitons in organic photovoltaics

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GRF: Molecular Engineering of Polyoxometalate (POM) and Self-Assembled Monolayer (SAM) Composites for Improving Efficiency and Stability of Organic and Perovskite 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

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Recycling of spin-triplet excitons in organic photovoltaics

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Projects

GRF: Molecular Engineering of Polyoxometalate (POM) and Self-Assembled Monolayer (SAM) Composites for Improving Efficiency and Stability of Organic and Perovskite 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