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Su N, Chen B, Ding J. Two Birds with One Stone: Polymerized Thermally Activated Delayed Fluorescence Small Molecules. Chemistry 2024; 30:e202304095. [PMID: 38246880 DOI: 10.1002/chem.202304095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 01/15/2024] [Accepted: 01/18/2024] [Indexed: 01/23/2024]
Abstract
Thermally activated delayed fluorescence (TADF) polymers show a great potential in low-cost, large-area and flexible full-color flat-panel displays. One of the most promising design rules is based on TADF+Linker, where a small molecular TADF unit is bonded to each other by a simple linker. Unlike the expensive vacuum deposition for small molecules, these polymerized TADF small molecules (Poly-TADF-SMs) are capable of cost-effective solution processing. Meanwhile, the good luminescent property of small molecular TADF emitters can be well inherited by Poly-TADF-SMs so as to bridge the efficiency gap between small molecules and polymers. Herein, we will highlight the recent progress of Poly-TADF-SMs, together with emphasis on their molecular design, photophysical and electroluminescence properties.
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Affiliation(s)
- Ning Su
- School of Chemical Science and Technology, Yunnan University, Kunming, 650091, P. R. China
| | - Bitian Chen
- School of Chemical Science and Technology, Yunnan University, Kunming, 650091, P. R. China
- Southwest United Graduate School, Kunming, 650092, P. R. China
| | - Junqiao Ding
- School of Chemical Science and Technology, Yunnan University, Kunming, 650091, P. R. China
- Southwest United Graduate School, Kunming, 650092, P. R. China
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2
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Hodée M, Massue J, Achelle S, Fihey A, Tondelier D, Ulrich G, Guen FRL, Katan C. Styrylpyrimidine chromophores with bulky electron-donating substituents: experimental and theoretical investigation. Phys Chem Chem Phys 2023; 25:32699-32708. [PMID: 38014523 DOI: 10.1039/d3cp03705c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Styrylpyrimidines with bulky 9,9-dimethylacridan, phenoxazine and phenothiazine electron-donating fragments were designed. Thermally activated delayed fluorescence (TADF) properties were expected for these structures. These chromophores exhibit peculiar emission properties. For 9,9-dimethylacridan and phenoxazine derivatives, a single emission highly sensitive to the polarity is observed in solution whereas for phenothiazine derivative a dual emission is observed in solution and is attributed to the coexistence of quasi-axial (Qax) and quasi-equatorial (Qeq) conformers. This study intends to understand through theoretical and experimental works, why the studied chromophores do not exhibit TADF properties, contrary to what was expected. The absence of phosphorescence both at room temperature and 77 K tends to indicate the impossibility to harvest triplet states in these systems. Wave-function based calculations show that for both conformers of the three chromophores the S1-T1 splitting is significantly larger than 0.2 eV. The second triplet state T2 of Qeq conformers is found very close in energy to the singlet S1 state, but S1 and T2 states possess similar charge transfer characters. This prevents efficient spin-orbit coupling between the states, which is consistent with the absence of TADF.
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Affiliation(s)
- Maxime Hodée
- Univ Rennes, ENSCR, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, F-35000 Rennes, France.
| | - Julien Massue
- Institut de Chimie et Procédés pour l'Energie, l'Environnement et la Santé (ICPEES), UMR CNRS 7515, Equipe Chimie Organique pour la Biologie, les Matériaux et l'Optique (COMBO) 25 Rue Becquerel, 67087 Strasbourg, Cedex 02, France.
| | - Sylvain Achelle
- Univ Rennes, ENSCR, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, F-35000 Rennes, France.
| | - Arnaud Fihey
- Univ Rennes, ENSCR, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, F-35000 Rennes, France.
| | - Denis Tondelier
- Laboratoire de Physique des Interfaces et des Couches Minces (LPICM), CNRS, Ecole Polytechnique, IP Paris, Palaiseau Cedex, France
- Université Paris-Saclay, CEA, CNRS, NIMBE, LICSEN, Gif-sur-Yvette, France
| | - Gilles Ulrich
- Institut de Chimie et Procédés pour l'Energie, l'Environnement et la Santé (ICPEES), UMR CNRS 7515, Equipe Chimie Organique pour la Biologie, les Matériaux et l'Optique (COMBO) 25 Rue Becquerel, 67087 Strasbourg, Cedex 02, France.
| | - Françoise Robin-le Guen
- Univ Rennes, ENSCR, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, F-35000 Rennes, France.
| | - Claudine Katan
- Univ Rennes, ENSCR, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, F-35000 Rennes, France.
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Xu L, Mo Y, Su N, Shi C, Sun N, Zhang Y, Duan L, Lu ZH, Ding J. D-O-A based organic phosphors for both aggregation-induced electrophosphorescence and host-free sensitization. Nat Commun 2023; 14:1678. [PMID: 36966127 PMCID: PMC10039947 DOI: 10.1038/s41467-023-37414-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 03/16/2023] [Indexed: 03/27/2023] Open
Abstract
Pure organic phosphors capable of room-temperature phosphorescence show a great potential in organic light-emitting diodes, while it is limited by the big challenge to realize efficient electroluminescence under electric excitation. Herein, we develop a class of organic phosphors based on acridine as the electron donor, triazine as the electron acceptor and oxygen as the bridge between them. Benefitting from the characteristic donor-oxygen-acceptor geometry, these compounds are found to behave an exciting aggregation-induced organic room-temperature electrophosphorescence, and achieve a record-high external quantum efficiency of 15.8% for non-doped devices. Furthermore, they can sensitize multi-resonant emitters in the absence of any additional wide bandgap host, leading to an effective narrowband emission with a peak external quantum efficiency of 26.4% and a small full-width at half maximum of 26 nm. The results clearly indicate that donor-oxygen-acceptor geometry is a promising strategy to design organic phosphors suitable for organic light-emitting diodes.
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Affiliation(s)
- Lulin Xu
- School of Chemical Science and Technology, Yunnan University, 650091, Kunming, People's Republic of China
| | - Yuhang Mo
- School of Chemical Science and Technology, Yunnan University, 650091, Kunming, People's Republic of China
| | - Ning Su
- School of Chemical Science and Technology, Yunnan University, 650091, Kunming, People's Republic of China
| | - Changshen Shi
- School of Physics and Astronomy, Yunnan University, 650091, Kunming, People's Republic of China.
| | - Ning Sun
- School of Physics and Astronomy, Yunnan University, 650091, Kunming, People's Republic of China
| | - Yuewei Zhang
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, 100084, Beijing, People's Republic of China.
| | - Lian Duan
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, 100084, Beijing, People's Republic of China
| | - Zheng-Hong Lu
- School of Physics and Astronomy, Yunnan University, 650091, Kunming, People's Republic of China
- Department of Materials Science and Engineering, University of Toronto, Toronto, ON, Canada
| | - Junqiao Ding
- School of Chemical Science and Technology, Yunnan University, 650091, Kunming, People's Republic of China.
- Southwest United Graduate School, 650092, Kunming, People's Republic of China.
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4
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Shizu K, Ren Y, Kaji H. Promoting Reverse Intersystem Crossing in Thermally Activated Delayed Fluorescence via the Heavy-Atom Effect. J Phys Chem A 2023; 127:439-449. [PMID: 36602533 DOI: 10.1021/acs.jpca.2c06287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Thermally activated delayed fluorescence (TADF) molecules are promising for realizing durable organic light-emitting diodes in all color regions. Fast reverse intersystem crossing (RISC) is a way of improving the device lifetime of TADF-based organic light-emitting diodes. To date, RISC rate constants (kRISC) of 108 s-1 have been reported for metal-free TADF molecules. Here, we report the heavy-atom effect on TADF and a molecular design for further promoting RISC. First, we reproduced all the relevant rate constants of a sulfur-containing TADF molecule (with kRISC of 108 s-1) via density functional theory. The role of the heavy-atom effect on the rapid RISC process was clarified. Our calculations also predicted that much larger kRISC (>1010 s-1) will be obtained for selenium- and tellurium-containing TADF molecules. However, a polonium-containing molecule promotes phosphorescence without exhibiting TADF, indicating that a too strong heavy-atom effect is unfavorable for achieving both rapid RISC and efficient TADF.
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Affiliation(s)
- Katsuyuki Shizu
- Institute for Chemical Research, Kyoto University, Uji, Kyoto611-0011, Japan
| | - Yongxia Ren
- Institute for Chemical Research, Kyoto University, Uji, Kyoto611-0011, Japan
| | - Hironori Kaji
- Institute for Chemical Research, Kyoto University, Uji, Kyoto611-0011, Japan
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A theoretical analysis on the electron and energy transfer between host and guest materials in phosphor–doped OLED. J Photochem Photobiol A Chem 2022. [DOI: 10.1016/j.jphotochem.2022.114058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Zou Y, Hu J, Yu M, Miao J, Xie Z, Qiu Y, Cao X, Yang C. High-Performance Narrowband Pure-Red OLEDs with External Quantum Efficiencies up to 36.1% and Ultralow Efficiency Roll-Off. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2201442. [PMID: 35588162 DOI: 10.1002/adma.202201442] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 04/28/2022] [Indexed: 06/15/2023]
Abstract
High-color-purity blue and green organic light-emitting diodes (OLEDs) have been resolved thanks to the development of B/N-based polycyclic multiple resonance (MR) emitters. However, due to the derivatization limit of B/N polycyclic structures, the design of red MR emitters remains challenging. Herein, a series of novel red MR emitters is reported by para-positioning N-π-N, O-π-O, B-π-B pairs onto a benzene ring to construct an MR central core. These emitters can be facilely and modularly synthesized, allowing for easy fine-tuning of emission spectra by peripheral groups. Moreover, these red MR emitters display excellent photophysical properties such as near-unity photoluminescence quantum yield (PLQY), fast radiative decay rate (kr ) up to 7.4 × 107 s-1 , and most importantly, narrowband emission with full-width at half-maximum (FWHM) of 32 nm. Incorporating these MR emitters, pure red OLEDs sensitized by phosphor realize state-of-the-art device performances with external quantum efficiency (EQE) exceeding 36%, ultralow efficiency roll-off (EQE remains as high as 25.1% at the brightness of 50 000 cd m-2 ), ultrahigh brightness over 130 000 cd m-2 , together with good device lifetime.
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Affiliation(s)
- Yang Zou
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, P. R. China
| | - Jiahao Hu
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, P. R. China
| | - Mingxin Yu
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, P. R. China
| | - Jingsheng Miao
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, P. R. China
| | - Ziyang Xie
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, P. R. China
| | - Yuntao Qiu
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, P. R. China
| | - Xiaosong Cao
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, P. R. China
| | - Chuluo Yang
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, P. R. China
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Sun Y, Qu H, Zhang J, Duan X, Zhang X. Room temperature phosphorescence, thermally activated delayed fluorescence and multicolor mechanochromic luminescence of emitters through molecular interaction and conformational modulations. Tetrahedron 2022. [DOI: 10.1016/j.tet.2022.132692] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Li M, Chen CF. TADF-Sensitized Fluorescent Enantiomers: A New Strategy for High-Efficiency Circularly Polarized Electroluminescence*. Chemistry 2021; 28:e202103550. [PMID: 34799883 DOI: 10.1002/chem.202103550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Indexed: 11/10/2022]
Abstract
A promising strategy of thermally activated delayed fluorescence (TADF) sensitized circularly polarized luminescence (CPL) has been proposed for improving the electroluminescence efficiencies of circularly polarized fluorescent emitters. Compared with chiral TADF emitters which suffer from the dilemma of small ΔEST accompanied by small kr , the TADF-sensitized CPL (TSCP) strategy using TADF molecules as sensitizers and CP-FL molecules as emitters might be the most promising method to construct high-performance circularly polarized organic light-emitting diodes (CP-OLEDs). Consequently, by taking advantage of the theoretically 100 % exciton utilization of TADF sensitizers, especially, by designing CP-FL emitters with high PLQY, narrow FWHM and large glum values, TSCP-type CP-OLEDs with excellent overall performances can be realized.
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Affiliation(s)
- Meng Li
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Chuan-Feng Chen
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China.,University of Chinese Academy of Sciences, Beijing, 100049, China
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9
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Polgar AM, Hudson ZM. Thermally activated delayed fluorescence materials as organic photosensitizers. Chem Commun (Camb) 2021; 57:10675-10688. [PMID: 34569578 DOI: 10.1039/d1cc04593h] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Photosensitizer molecules play a crucial role in materials and life sciences. Efforts to improve their performance and reduce the associated costs are therefore vital for advancing environmentally friendly light-driven technologies. In this Feature Article, we describe the use of photosensitizers that make use of thermally activated delayed fluorescence (TADF), their benefits compared to conventional fluorescent and phosphorescent sensitizers, and the efforts of our group and others to develop emitters with application-tailored properties. The key feature is the diversity of accessible excited state pathways, which may be tuned by molecular and supramolecular approaches to suit a particular problem. This unique property has allowed TADF emitters to become competitive for applications including TADF-sensitized fluorescence in light emitting diodes and chemical sensing, organic long persistent luminescence, photodynamic therapy, and non-coherent photon upconversion.
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Affiliation(s)
- Alexander M Polgar
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, V6T 1Z1, Canada.
| | - Zachary M Hudson
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, V6T 1Z1, Canada.
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Li J, Gong H, Zhang J, Liu H, Tao L, Wang Y, Guo Q. Efficient Exciplex-Based Deep-Blue Organic Light-Emitting Diodes Employing a Bis(4-fluorophenyl)amine-Substituted Heptazine Acceptor. Molecules 2021; 26:5568. [PMID: 34577041 PMCID: PMC8466596 DOI: 10.3390/molecules26185568] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Revised: 09/03/2021] [Accepted: 09/10/2021] [Indexed: 11/25/2022] Open
Abstract
The realization of a deep-blue-emitting exciplex system is a herculean task in the field of organic light-emitting diodes (OLEDs) on account of a large red-shifted and broadened exciplex emission spectrum in comparison to those of the corresponding single compounds. Herein, 2,5,8-tris(di(4-fluorophenyl)amine)-1,3,4,6,7,9,9b-heptaazaphenalene (HAP-3FDPA) was designed as an electron acceptor by integrating three bis(4-fluorophenyl)amine groups into a heptazine core, while 1,3-di(9H-carbazol-9-yl)benzene (mCP) possessing two electron-donating carbazole moieties was chosen as the electron donor. Excitingly, the exciplex system of 8 wt% HAP-3FDPA:mCP exhibited deep-blue emission and a high photoluminescence quantum yield of 53.2%. More importantly, an OLED containing this exciplex system as an emitting layer showed deep-blue emission with Commission Internationale de l'Eclairage coordinates of (0.16, 0.12), a peak luminance of 15,148 cd m-2, and a rather high maximum external quantum efficiency of 10.2% along with a low roll-off. This study not only reports an efficient exciplex-based deep-blue emitter but also presents a feasible pathway to construct highly efficient deep-blue OLEDs based on exciplex systems.
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Affiliation(s)
- Jie Li
- College of Optoelectronic Engineering, Chengdu University of Information Technology, Chengdu 610225, China; (J.L.); (H.G.); (J.Z.); (H.L.); (L.T.)
| | - Heqi Gong
- College of Optoelectronic Engineering, Chengdu University of Information Technology, Chengdu 610225, China; (J.L.); (H.G.); (J.Z.); (H.L.); (L.T.)
| | - Jincheng Zhang
- College of Optoelectronic Engineering, Chengdu University of Information Technology, Chengdu 610225, China; (J.L.); (H.G.); (J.Z.); (H.L.); (L.T.)
| | - Hui Liu
- College of Optoelectronic Engineering, Chengdu University of Information Technology, Chengdu 610225, China; (J.L.); (H.G.); (J.Z.); (H.L.); (L.T.)
| | - Li Tao
- College of Optoelectronic Engineering, Chengdu University of Information Technology, Chengdu 610225, China; (J.L.); (H.G.); (J.Z.); (H.L.); (L.T.)
| | - Yanqing Wang
- College of Polymer Science and Engineering, Sichuan University, Chengdu 610065, China;
| | - Qiang Guo
- College of Optoelectronic Engineering, Chengdu University of Information Technology, Chengdu 610225, China; (J.L.); (H.G.); (J.Z.); (H.L.); (L.T.)
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Poisson J, Polgar AM, Fromel M, Pester CW, Hudson ZM. Preparation of Patterned and Multilayer Thin Films for Organic Electronics via Oxygen‐Tolerant SI‐PET‐RAFT. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202107830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Jade Poisson
- Department of Chemistry The University of British Columbia 2036 Main Mall Vancouver British Columbia V6T 1Z1 Canada
| | - Alexander M. Polgar
- Department of Chemistry The University of British Columbia 2036 Main Mall Vancouver British Columbia V6T 1Z1 Canada
| | - Michele Fromel
- Department of Chemical Engineering Department of Chemistry Department of Materials Science and Engineering The Pennsylvania State University University Park PA 16802 USA
| | - Christian W. Pester
- Department of Chemical Engineering Department of Chemistry Department of Materials Science and Engineering The Pennsylvania State University University Park PA 16802 USA
| | - Zachary M. Hudson
- Department of Chemistry The University of British Columbia 2036 Main Mall Vancouver British Columbia V6T 1Z1 Canada
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12
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Polgar AM, Poisson J, Christopherson CJ, Hudson ZM. Enhancement of Red Thermally Assisted Fluorescence in Bottlebrush Block Copolymers. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c01524] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Alexander M. Polgar
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada V6T 1Z1
| | - Jade Poisson
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada V6T 1Z1
| | - Cheyenne J. Christopherson
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada V6T 1Z1
| | - Zachary M. Hudson
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada V6T 1Z1
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13
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Li M, Wang M, Wang Y, Feng L, Chen C. High‐Efficiency Circularly Polarized Electroluminescence from TADF‐Sensitized Fluorescent Enantiomers. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202108011] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Meng Li
- Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Molecular Recognition and Function Institute of Chemistry Chinese Academy of Sciences Beijing 100190 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Mei‐Ying Wang
- School of Chemistry and Chemical Engineering Department Shanxi University Taiyuan 030006 China
| | - Yin‐Feng Wang
- Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Molecular Recognition and Function Institute of Chemistry Chinese Academy of Sciences Beijing 100190 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Liheng Feng
- School of Chemistry and Chemical Engineering Department Shanxi University Taiyuan 030006 China
| | - Chuan‐Feng Chen
- Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Molecular Recognition and Function Institute of Chemistry Chinese Academy of Sciences Beijing 100190 China
- University of Chinese Academy of Sciences Beijing 100049 China
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14
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Li M, Wang MY, Wang YF, Feng L, Chen CF. High-Efficiency Circularly Polarized Electroluminescence from TADF-Sensitized Fluorescent Enantiomers. Angew Chem Int Ed Engl 2021; 60:20728-20733. [PMID: 34288304 DOI: 10.1002/anie.202108011] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/16/2021] [Indexed: 01/01/2023]
Abstract
A couple of fluorescent enantiomers, which are suitable for the emitters of high-efficiency TADF-sensitized CP-OLEDs, have been developed. The enantiomers show configurational stability, high PLQY of 98 %, large kr of 7.8×107 s-1 , and intense CPL activities with |glum | values of about 2.5×10-3 . Notably, by using matchable TADF sensitizer, the enantiomers were then exploited as emitter to fabricate CP-OLEDs. The TADF-sensitized CP-OLEDs not only show mirror-image CPEL activities with gEL values of +1.8×10-3 and -1.4×10-3 , but also display fast start-up featuring with low VT of 3.0 V as well as driving voltage of 4.8 V at 10 000 cd m-2 . Meaningfully, the TADF-sensitized fluorescent devices show high EQEmax of 21.5 % and extremely low efficiency roll-off, whose EQEs are 21.2 % and 15.3 % at 1000 and 10 000 cd m-2 , respectively. The obtained EQEs are comparable to those of CP-TADF emitters, which provides a promising perspective to break through the EL efficiency limit of CP-FL emitters.
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Affiliation(s)
- Meng Li
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Mei-Ying Wang
- School of Chemistry and Chemical Engineering Department, Shanxi University, Taiyuan, 030006, China
| | - Yin-Feng Wang
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Liheng Feng
- School of Chemistry and Chemical Engineering Department, Shanxi University, Taiyuan, 030006, China
| | - Chuan-Feng Chen
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
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15
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Poisson J, Polgar AM, Fromel M, Pester CW, Hudson ZM. Preparation of Patterned and Multilayer Thin Films for Organic Electronics via Oxygen-Tolerant SI-PET-RAFT. Angew Chem Int Ed Engl 2021; 60:19988-19996. [PMID: 34337845 DOI: 10.1002/anie.202107830] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Indexed: 11/10/2022]
Abstract
An oxygen-tolerant approach is described for preparing surface-tethered polymer films of organic semiconductors directly from electrode substrates using polymer brush photolithography. A photoinduced electron transfer-reversible addition-fragmentation chain transfer (PET-RAFT) approach was used to prepare multiblock polymer architectures with the structures of multi-layer organic light-emitting diodes (OLEDs), including electron-transport, emissive, and hole-transport layers. The preparation of thermally activated delayed fluorescence (TADF) and thermally assisted fluorescence (TAF) trilayer OLED architectures are described. By using direct photomasking as well as a digital micromirror device, we also show that the surface-initiated (SI)-PET-RAFT approach allows for enhanced control over layer thickness, and spatial resolution in polymer brush patterning at low cost.
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Affiliation(s)
- Jade Poisson
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, V6T 1Z1, Canada
| | - Alexander M Polgar
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, V6T 1Z1, Canada
| | - Michele Fromel
- Department of Chemical Engineering, Department of Chemistry, Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Christian W Pester
- Department of Chemical Engineering, Department of Chemistry, Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Zachary M Hudson
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, V6T 1Z1, Canada
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Efficient Deep-Blue Electroluminescence Employing Heptazine-Based Thermally Activated Delayed Fluorescence. PHOTONICS 2021. [DOI: 10.3390/photonics8080293] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We report an efficient deep-blue organic light-emitting diode (OLED) based on a heptazine-based thermally activated delayed fluorescent (TADF) emitter, 2,5,8-tris(diphenylamine)-tri-s-triazine (HAP-3DPA). The deep-blue-emitting compound, HAP-3DPA, was designed and synthesized by combining the relatively rigid electron-accepting heptazine core with three electron-donating diphenylamine units. Due to the rigid molecular structure and intramolecular charge transfer characteristics, HAP-3DPA in solid state presented a high photoluminescence quantum yield of 67.0% and obvious TADF nature with a short delayed fluorescent lifetime of 1.1 μs. Most importantly, an OLED incorporating HAP-3DPA exhibited deep-blue emission with Commission Internationale de l’Eclairage (CIE) coordinates of (0.16, 0.13), a peak luminance of 10,523 cd/m−2, and a rather high external quantum efficiency of 12.5% without any light out-coupling enhancement. This finding not only reports an efficient deep-blue TADF molecule, but also presents a feasible pathway to construct high-performance deep-blue emitters and devices based on the heptazine skeleton.
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Dubey DK, Thakur D, Yadav RAK, Ram Nagar M, Liang TW, Ghosh S, Jou JH. High-Throughput Virtual Screening of Host Materials and Rational Device Engineering for Highly Efficient Solution-Processed Organic Light-Emitting Diodes. ACS APPLIED MATERIALS & INTERFACES 2021; 13:26204-26217. [PMID: 34048214 DOI: 10.1021/acsami.1c04015] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The appropriate choice of host and electron-transporting material (ETM) plays a very crucial role in the generation and collection of radiative excitons in the desired recombination zone of organic light-emitting diodes (OLEDs). Due to the sustainable development of material organic chemistry, there is a big library of functional materials that leads to uncountable combinations of device structures, which might achieve a desirable high device performance. However, there is no appropriate methodology available for the fast virtual screening of organic materials and designing a suitable device structure. Here, we have used the electrical software package SETFOS 4.5 for high-throughput virtual screening of host materials and developed a highly efficient multistack OLED device structure. To further enhance the device performance, a co-host approach has been used, and the final device structure has also been optimized with two different ETMs. The best-optimized Ir(ppy)3-based solution-processed green OLED device exhibited a maximum power efficiency (PE) of 83.20 lm/W and brightness of 61,362 cd/m2 with a driving voltage of 2.1 V without using any light extraction outcoupling techniques, which is the best among the OLEDs in its own category. The developed device structure has also been utilized to fabricate highly efficient blue hazard-free low-color temperature OLEDs for a physiologically friendly light at night. The resultant 2083 K OLED device displayed a maximum PE of 51.4 lm/W and luminance of 44,548 cd/m2 with a turn-on voltage of 2.1 V that is also 42 and 104 times safer in terms of retinal protection and ∼4 and ∼11 times safer in terms of melatonin generation when compared with those of a real candle and incandescent bulb, respectively. The observed excellent device performance may be attributed to the balanced charge carrier in the recombination zone, broader emissive layer due to a mixed-host system, less accumulation of charges at the injecting surfaces, well-aligned triplet energy and molecular orbital energy level of the host and guest, and high electron mobility and enhanced hole blocking ability of the employed ETM in the designed OLED device structure.
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Affiliation(s)
- Deepak Kumar Dubey
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan, Republic of China
| | - Diksha Thakur
- School of Basic Sciences, IIT Mandi, Mandi, Himachal Pradesh 175005, India
| | - Rohit Ashok Kumar Yadav
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan, Republic of China
| | - Mangey Ram Nagar
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan, Republic of China
| | - Tzu-Wei Liang
- Global Science Instruments Co., New Taipei City 23144, Taiwan, Republic of China
| | - Subrata Ghosh
- School of Basic Sciences, IIT Mandi, Mandi, Himachal Pradesh 175005, India
| | - Jwo-Huei Jou
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan, Republic of China
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Polgar AM, Tonge CM, Christopherson CJ, Paisley NR, Reyes AC, Hudson ZM. Thermally Assisted Fluorescent Polymers: Polycyclic Aromatic Materials for High Color Purity and White-Light Emission. ACS APPLIED MATERIALS & INTERFACES 2020; 12:38602-38613. [PMID: 32846499 DOI: 10.1021/acsami.0c07892] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Thermally activated delayed fluorescence (TADF) sensitization of fluorescence is a promising strategy to improve the color purity and operational lifetime of conventional TADF organic light-emitting diodes (OLEDs). Here, we propose a new design strategy for TADF-sensitized fluorescence based on acrylic polymers with a pendant energy-harvesting host, a TADF sensitizer, and fluorescent emitter monomers. Fluorescent emitters were rationally designed from a series of homologous polycyclic aromatic amines, resulting in efficient and color-pure polymeric fluorophores capable of harvesting both singlet and triplet excitons. Macromolecular analogues of blue, green, and yellow fourth-generation OLED emissive layers were prepared in a facile manner by Cu(0) reversible deactivation radical polymerization, with emission quantum yields up to 0.83 in air and narrow emission bands with full width at half-maximum as low as 57 nm. White-light emission can easily be achieved by enforcing incomplete energy transfer between a deep blue TADF sensitizer and yellow fluorophore to yield a single white-emissive polymer with CIE coordinates (0.33, 0.39) and quantum yield 0.77. Energy transfer to the fluorescent emitters occurs at rates of 1-4 × 108 s-1, significantly faster than deactivation caused by internal conversion or intersystem crossing. Rapid energy transfer facilitates high triplet exciton utilization and efficient sensitized emission, even when TADF emitters with a low quantum yield are used as photosensitizers. Our results indicate that a broad library of untapped polymers exhibiting efficient TADF-sensitized fluorescence should be readily accessible from known TADF materials, including many monomers previously thought unsuitable for use in OLEDs.
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Affiliation(s)
- Alexander M Polgar
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Christopher M Tonge
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Cheyenne J Christopherson
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Nathan R Paisley
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Annelie C Reyes
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Zachary M Hudson
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
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Abstract
Thermally activated delayed fluorescence (TADF) and TADF-organic light-emitting diodes (OLEDs) systems are being given increasing attention in research nowadays. Much more work has been done for organic-based materials in this field, but the use of TADF organometallic systems has also emerged in recent years. In particular, TADF-based gold compounds have not been particularly well-explored, with a higher number of examples of Au(I)-molecules and fewer for the higher oxidation state Au(III) derivatives. Nevertheless, the novelty and observed results deserve attention. A careful analysis has been performed in this review by classifying the reported compounds into two different groups regarding the oxidation state of the metal, and within each group, the ancillary ligands. Specific examples to illustrate their potential applications are included in the different sections.
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Liu J, Zhou K, Wang D, Deng C, Duan K, Ai Q, Zhang Q. Pyrazine-Based Blue Thermally Activated Delayed Fluorescence Materials: Combine Small Singlet-Triplet Splitting With Large Fluorescence Rate. Front Chem 2019; 7:312. [PMID: 31165054 PMCID: PMC6536661 DOI: 10.3389/fchem.2019.00312] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 04/18/2019] [Indexed: 01/21/2023] Open
Abstract
Metal-free thermally activated delayed fluorescence (TADF) emitters have emerged as promising candidate materials for highly efficient and low-cost organic light-emitting diodes (OLEDs). Here, a novel acceptor 2-cyanopyrazine is selected for the construction of blue TADF molecules via computer-assisted molecular design. Both theoretical prediction and experimental photophysical data indicate a small S1-T1 energy gap (ΔEST) and a relative large fluorescence rate (kF) in an o-phenylene-bridged 2-cyanopyrazine/3,6-di-tert-butylcarbazole compound (TCzPZCN). The kF value of 3.7 × 107 s−1 observed in a TCzPZCN doped film is among the highest in the TADF emitters with a ΔEST smaller than 0.1 eV. Blue TADF emission is observed in a TCzPZCN doped film with a short TADF lifetime of 1.9 μs. The OLEDs using TCzPZCN as emitter exhibit a maximum external quantum efficiency (EQE) of 7.6% with low-efficiency roll-off. A sky-blue device containing a derivative of TCzPZCN achieves an improved EQE maximum of 12.2% by suppressing the non-radiative decay at T1.
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Affiliation(s)
- Junyuan Liu
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, China
| | - Keren Zhou
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, China
| | - Dan Wang
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, China
| | - Chao Deng
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, China
| | - Ke Duan
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, China
| | - Qi Ai
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, China
| | - Qisheng Zhang
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, China
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