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Sayner T, Ruseckas A, Harwell JR, Samuel IDW. Exciton Diffusion to Low Energy Sites of the Acceptor Drives Charge Photogeneration in D18:Y6 Solar Cells. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2024; 128:19319-19328. [PMID: 39564142 PMCID: PMC11571220 DOI: 10.1021/acs.jpcc.4c06706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2024] [Revised: 10/06/2024] [Accepted: 10/09/2024] [Indexed: 11/21/2024]
Abstract
We have investigated charge generation pathways in efficient organic photovoltaic blends of the polymer donor D18 and the small-molecule acceptor Y6 using transient absorption and time-resolved fluorescence spectroscopies. We find that energy transfer from D18 to Y6 outcompetes electron transfer and is followed by exciton diffusion from regions of the disordered Y6 phase to Y6 aggregates before hole transfer to D18. Aggregation of Y6 molecules increases their ionization energy by ∼0.3 eV and provides a driving force for hole transfer from Y6 excitons and spontaneously generated charge pairs to D18. We observed ultrafast depolarization of the Y6 ground-state bleaching in <200 fs, which indicates delocalization of primary excitons in Y6 aggregates. This delocalization can explain the spontaneous generation of charge pairs in neat Y6 films and Y6-rich blends. Our results show that subtle aggregation control of the low-energy absorber can be used for balancing photocurrent generation with low voltage loss in photovoltaic blends.
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Affiliation(s)
- Thomas Sayner
- Organic Semiconductor Centre, SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9SS, U.K
| | - Arvydas Ruseckas
- Organic Semiconductor Centre, SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9SS, U.K
| | - Jonathon R Harwell
- Organic Semiconductor Centre, SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9SS, U.K
| | - Ifor D W Samuel
- Organic Semiconductor Centre, SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9SS, U.K
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Sun Y, Wu L, Zhu L, Baryshnikov GV, Zhang F, Li X. Recent Advances in Thermally Activated Delayed Fluorescence-Based Organic Afterglow Materials. SMALL METHODS 2024:e2400982. [PMID: 39460397 DOI: 10.1002/smtd.202400982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2024] [Revised: 09/07/2024] [Indexed: 10/28/2024]
Abstract
Thermally activated delayed fluorescence (TADF)-based materials are attracting widespread attention for different applications owing to their ability of harvesting both singlet and triplet excitons without noble metals in their structures. As compared to the conventional fluorescence and room-temperature phosphorescence pathways, TADF originates from the reverse intersystem crossing process from the excited triplet state (T1) to the singlet state (S1). Therefore, TADF emitters enabling activated and long lifetime T1 excitons are potential candidates for generating long-lived afterglow emission, an effect that can still be observed for a while by the naked eye after the removal of the excitation light source. Recently, TADF-based organic afterglow materials featuring high photoluminescence quantum yields and long lifetimes above 100 ms under ambient conditions, have emerged for advanced information security, high-contrast biological imaging, optoelectronic devices, and intelligent sensors, whereas the related systematic review is still lacking. Herein, the recent progress in TADF-based organic afterglow materials is summarized and an overview of the photophysical mechanism, design strategies, and the performances for relevant applications is given. In addition, the challenge and perspective of this area are given at the end of the review.
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Affiliation(s)
- Yuyu Sun
- College of Energy Materials and Chemistry, Inner Mongolia University, Hohhot, 010020, P. R. China
| | - Leiying Wu
- College of Energy Materials and Chemistry, Inner Mongolia University, Hohhot, 010020, P. R. China
| | - Liangliang Zhu
- Department of Macromolecular Science, State Key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai, 200438, China
| | - Glib V Baryshnikov
- Laboratory of Organic Electronics, Department of Science and Technology, Linköping University, Norrköping, SE-601 74, Sweden
| | - Fan Zhang
- College of Energy Materials and Chemistry, Inner Mongolia University, Hohhot, 010020, P. R. China
- Department of Chemistry, State Key Laboratory of Molecular Engineering of Polymers, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials and iChem, Fudan University, Shanghai, 200433, P. R. China
| | - Xuping Li
- College of Energy Materials and Chemistry, Inner Mongolia University, Hohhot, 010020, P. R. China
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Ding P, Yang D, Yang S, Ge Z. Stability of organic solar cells: toward commercial applications. Chem Soc Rev 2024; 53:2350-2387. [PMID: 38268469 DOI: 10.1039/d3cs00492a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2024]
Abstract
Organic solar cells (OSCs) have attracted a great deal of attention in the field of clean solar energy due to their advantages of transparency, flexibility, low cost and light weight. Introducing them to the market enables seamless integration into buildings and windows, while also supporting wearable, portable electronics and internet-of-things (IoT) devices. With the development of photovoltaic materials and the optimization of fabrication technology, the power conversion efficiencies (PCEs) of OSCs have rapidly improved and now exceed 20%. However, there is a significant lack of focus on material stability and device lifetime, causing a severe hindrance to commercial applications. In this review, we carefully review important strategies employed to improve the stability of OSCs over the past three years from the perspectives of material design and device engineering. Furthermore, we analyze and discuss the current important progress in terms of air, light, thermal and mechanical stability. Finally, we propose the future research directions to overcome the challenges in achieving highly stable OSCs. We expect that this review will contribute to solving the stability problem of OSCs, eventually paving the way for commercial applications in the near future.
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Affiliation(s)
- Pengfei Ding
- Zhejiang Engineering Research Center for Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China.
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Daobin Yang
- Zhejiang Engineering Research Center for Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China.
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shuncheng Yang
- Zhejiang Engineering Research Center for Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China.
| | - Ziyi Ge
- Zhejiang Engineering Research Center for Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China.
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
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Lüer L, Wang R, Liu C, Dube H, Heumüller T, Hauch J, Brabec CJ. Maximizing Performance and Stability of Organic Solar Cells at Low Driving Force for Charge Separation. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2305948. [PMID: 38039433 PMCID: PMC10853714 DOI: 10.1002/advs.202305948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 10/19/2023] [Indexed: 12/03/2023]
Abstract
Thanks to the development of novel electron acceptor materials, the power conversion efficiencies (PCE) of organic photovoltaic (OPV) devices are now approaching 20%. Further improvement of PCE is complicated by the need for a driving force to split strongly bound excitons into free charges, causing voltage losses. This review discusses recent approaches to finding efficient OPV systems with minimal driving force, combining near unity quantum efficiency (maximum short circuit currents) with optimal energy efficiency (maximum open circuit voltages). The authors discuss apparently contradicting results on the amount of exciton binding in recent literature, and approaches to harmonize the findings. A comprehensive view is then presented on motifs providing a driving force for charge separation, namely hybridization at the donor:acceptor interface and polarization effects in the bulk, of which quadrupole moments (electrostatics) play a leading role. Apart from controlling the energies of the involved states, these motifs also control the dynamics of recombination processes, which are essential to avoid voltage and fill factor losses. Importantly, all motifs are shown to depend on both molecular structure and process conditions. The resulting high dimensional search space advocates for high throughput (HT) workflows. The final part of the review presents recent HT studies finding consolidated structure-property relationships in OPV films and devices from various deposition methods, from research to industrial upscaling.
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Affiliation(s)
- Larry Lüer
- Institute of Materials for Electronics and Energy Technology (i‐MEET)Friedrich‐Alexander‐Universität Erlangen‐NürnbergMartensstrasse 791058ErlangenGermany
| | - Rong Wang
- Institute of Materials for Electronics and Energy Technology (i‐MEET)Friedrich‐Alexander‐Universität Erlangen‐NürnbergMartensstrasse 791058ErlangenGermany
- Erlangen Graduate School in Advanced Optical Technologies (SAOT)Paul‐Gordan‐Straße 691052ErlangenGermany
| | - Chao Liu
- Institute of Materials for Electronics and Energy Technology (i‐MEET)Friedrich‐Alexander‐Universität Erlangen‐NürnbergMartensstrasse 791058ErlangenGermany
| | - Henry Dube
- Department Chemistry and PharmacyFriedrich‐Alexander‐Universität Erlangen‐NürnbergNikolaus‐Fiebiger‐Straße 1091058ErlangenGermany
| | - Thomas Heumüller
- Institute of Materials for Electronics and Energy Technology (i‐MEET)Friedrich‐Alexander‐Universität Erlangen‐NürnbergMartensstrasse 791058ErlangenGermany
| | - Jens Hauch
- Helmholtz‐Institute Erlangen‐Nürnberg (HI‐ERN)Immerwahrstraße 291058ErlangenGermany
| | - Christoph J. Brabec
- Institute of Materials for Electronics and Energy Technology (i‐MEET)Friedrich‐Alexander‐Universität Erlangen‐NürnbergMartensstrasse 791058ErlangenGermany
- Helmholtz‐Institute Erlangen‐Nürnberg (HI‐ERN)Immerwahrstraße 291058ErlangenGermany
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Park K, Kim JH, Jin JS, Moon H, Oh J, Lee S, Ki T, Jeong HS, Jeong S, Jang SY, Kang H, Lee K. Overcoming the Interfacial Photocatalytic Degradation of Nonfullerene Acceptor-Based Organic Photovoltaics by Introducing a UV-A-Insensitive Titanium Suboxide Layer. ACS APPLIED MATERIALS & INTERFACES 2024; 16:3778-3785. [PMID: 38268146 DOI: 10.1021/acsami.3c15801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2024]
Abstract
Although recent dramatic advances in power conversion efficiencies (PCEs) have resulted in values over 19%, the poor photostability of organic photovoltaics (OPVs) has been a serious bottleneck to their commercialization. The photocatalytic effect, which is caused by incident ultraviolet-A (UV-A, 320-400 nm) light in the most commonly used zinc oxide (ZnOX) electron transport layer (ETL), significantly deteriorates the photostability of OPVs. In this work, we develop a new and facile method to enhance the photostability of nonfullerene acceptor-based OPVs by introducing UV-A-insensitive titanium suboxide (TiOX) ETL. Through an in-depth analysis of mass information at the interface between the ETL and photoactive layer, we confirm that the UV-A-insensitive TiOX suppresses the photocatalytic effect. The resulting device employing the TiOX ETL shows excellent photostability, obtaining 80% of the initial PCE for up to 200 h under 1 sun illumination, which is 10 times longer than that of the conventional ZnOX system (19 h).
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Affiliation(s)
- Kiyoung Park
- School of Materials Science and Engineering (SMSE), Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
- Heeger Center for Advanced Materials (HCAM) and Research Institute for Solar and Sustainable Energies (RISE), Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| | - Ju-Hyeon Kim
- School of Materials Science and Engineering (SMSE), Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
- Heeger Center for Advanced Materials (HCAM) and Research Institute for Solar and Sustainable Energies (RISE), Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| | - Jong Sung Jin
- Korea Basic Science Institute (KBSI), Busan 46742, Republic of Korea
| | - Heehun Moon
- Korea Basic Science Institute (KBSI), Busan 46742, Republic of Korea
| | - Juhui Oh
- School of Materials Science and Engineering (SMSE), Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
- Heeger Center for Advanced Materials (HCAM) and Research Institute for Solar and Sustainable Energies (RISE), Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| | - Sanseong Lee
- School of Materials Science and Engineering (SMSE), Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
- Heeger Center for Advanced Materials (HCAM) and Research Institute for Solar and Sustainable Energies (RISE), Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| | - Taeyoon Ki
- School of Materials Science and Engineering (SMSE), Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
- Heeger Center for Advanced Materials (HCAM) and Research Institute for Solar and Sustainable Energies (RISE), Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| | - Hyeon-Seok Jeong
- Heeger Center for Advanced Materials (HCAM) and Research Institute for Solar and Sustainable Energies (RISE), Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| | - Soyeong Jeong
- Heeger Center for Advanced Materials (HCAM) and Research Institute for Solar and Sustainable Energies (RISE), Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| | - Soo-Young Jang
- Heeger Center for Advanced Materials (HCAM) and Research Institute for Solar and Sustainable Energies (RISE), Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| | - Hongkyu Kang
- Heeger Center for Advanced Materials (HCAM) and Research Institute for Solar and Sustainable Energies (RISE), Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| | - Kwanghee Lee
- School of Materials Science and Engineering (SMSE), Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
- Heeger Center for Advanced Materials (HCAM) and Research Institute for Solar and Sustainable Energies (RISE), Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
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