1
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Gou Q, Guan J, Zhang L, Ai X. Phenyl Derivatives Modulate the Luminescent Properties and Stability of CzBTM-Type Radicals. Molecules 2024; 29:2900. [PMID: 38930965 PMCID: PMC11206717 DOI: 10.3390/molecules29122900] [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: 05/21/2024] [Revised: 06/15/2024] [Accepted: 06/16/2024] [Indexed: 06/28/2024] Open
Abstract
The distinctive electron structures of luminescent radicals offer considerable potential for a diverse array of applications. Up to now, the luminescent properties of radicals have been modulated through the introduction of electron-donating substituents, predominantly derivatives of carbazole and polyaromatic amines with more and more complicated structures and redshifted luminescent spectra. Herein, four kinds of (N-carbazolyl)bis(2,4,6-tirchlorophenyl)-methyl (CzBTM) radicals, Ph2CzBTM, Mes2CzBTM, Ph2PyIDBTM, and Mes2PyIDBTM, were synthesized and characterized by introducing simple phenyl and 2,4,6-trimethylphenyl groups to CzBTM and PyIDBTM. These radicals exhibit rare blueshifted emission spectra compared to their parent radicals. Furthermore, modifications to CzBTM significantly enhanced the photoluminescence quantum yields (PLQYs), with a highest PLQY of 21% for Mes2CzBTM among CzBTM-type radicals. Additionally, the molecular structures, photophysical properties of molecular orbitals, and stability of the four radicals were systematically investigated. This study provides a novel strategy for tuning the luminescent color of radicals to shorter wavelengths and improving thermostability.
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Affiliation(s)
- Quanquan Gou
- School of Materials Science and Engineering, Hainan University, No 58, Renmin Avenue, Haikou 570228, China
| | - Jiahao Guan
- School of Materials Science and Engineering, Hainan University, No 58, Renmin Avenue, Haikou 570228, China
| | - Lintao Zhang
- School of Materials Science and Engineering, Hainan University, No 58, Renmin Avenue, Haikou 570228, China
- Collaborative Innovation Center of Marine Science and Technology, Hainan University, No 58, Renmin Avenue, Haikou 570228, China
| | - Xin Ai
- School of Materials Science and Engineering, Hainan University, No 58, Renmin Avenue, Haikou 570228, China
- Collaborative Innovation Center of Marine Science and Technology, Hainan University, No 58, Renmin Avenue, Haikou 570228, China
- Collaborative Innovation Center of Information Technology, Hainan University, No 58, Renmin Avenue, Haikou 570228, China
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2
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Arnold ME, Schoeneburg L, Lamla M, Kuehne AJC. Water-Soluble Trityl Radicals for Fluorescence Imaging. Molecules 2024; 29:995. [PMID: 38474507 DOI: 10.3390/molecules29050995] [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: 02/03/2024] [Revised: 02/21/2024] [Accepted: 02/22/2024] [Indexed: 03/14/2024] Open
Abstract
Stable tris(trichlorophenyl)methyl radicals have gained interest as all-organic bioimaging agents combining fluorescent and paramagnetic properties. However, cellular uptake has so far only been reported for nanoparticles, because molecular hydrophobic trityl radicals are not soluble in aqueous media. Here, we report the synthesis and characterization of new water-soluble tris(trichlorophenyl)methyl radical derivatives exhibiting red doublet emission. Solubility in water is achieved through functionalization with oligoethylene glycol (OEG) chains. The emission behavior of OEG functionalized trityl radicals is studied in polar environments. Donor-functionalization with carbazole evokes a charge-transfer excited state that is efficiently quenched in polar solvents. In contrast, click-reaction mediated attachment of OEG-azide and trityl acetylene furnishes a triazole functionalized radical with locally excited states and emission in water. Confocal fluorescence microscopy proves successful uptake of the material by macrophages in cell culture, showing the potential of our water soluble trityl radical for fluorescence bioimaging.
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Affiliation(s)
- Mona E Arnold
- Institute of Macromolecular and Organic Chemistry, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Larissa Schoeneburg
- Institute of Macromolecular and Organic Chemistry, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Markus Lamla
- Institute of Macromolecular and Organic Chemistry, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Alexander J C Kuehne
- Institute of Macromolecular and Organic Chemistry, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
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3
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Li H, Lei H, Ma S, Song T, Li Y, Yu H. Capturing Doublet Intermediate Emitters by Chemically Crosslinking Confinement towards Spatiotemporal Encryption. Angew Chem Int Ed Engl 2024; 63:e202312185. [PMID: 37985243 DOI: 10.1002/anie.202312185] [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: 08/21/2023] [Revised: 11/16/2023] [Accepted: 11/17/2023] [Indexed: 11/22/2023]
Abstract
Photoluminescence is one of the most meticulous ways to manipulate light energy. Typical photoluminescent emitters are mostly stable substances with a pure photophysical process of spontaneous photon-emission from their excited states. Intermediate emitters are elusive attributing to their synchronous energy transfer process including photophysical and incomplete photochemical pathways. An intermediate emitter containing radicals is more difficult to be observed due to its inherent chemical reactivity. Here, these challenges are overcome by spontaneously formed space limitations in polymer crosslinking networks meanwhile chemically active intermediates are captured. These doublet intermediates exhibit unique long-wavelength emissions under chemically crosslinking confinement conditions, and their luminous mechanism provides a novel perspective for designing intermediate emitters with liquid-crystal character and photoresponsive features towards spatiotemporal encryption, promising for the detection of photochemical reactions and the development of fascinating luminescent systems.
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Affiliation(s)
- Haomin Li
- School of Materials Science and Engineering, Beijing Advanced Innovation Centre for Biomedical Engineering, Beihang University, Beijing, 100191, China
- School of Materials Science and Engineering, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Peking University, Beijing, 100871, China
| | - Huanyu Lei
- South China Advanced Institute for Soft Matter Science and Technology, School of Molecular Science and Engineering, South China University of Technology, Guangzhou, 510641, China
| | - Shudeng Ma
- School of Materials Science and Engineering, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Peking University, Beijing, 100871, China
| | - Tianfu Song
- School of Materials Science and Engineering, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Peking University, Beijing, 100871, China
| | - Yan Li
- School of Materials Science and Engineering, Beijing Advanced Innovation Centre for Biomedical Engineering, Beihang University, Beijing, 100191, China
| | - Haifeng Yu
- School of Materials Science and Engineering, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Peking University, Beijing, 100871, China
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4
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Wang X, Wu C, Wang Z, Liu W. When do tripdoublet states fluoresce? A theoretical study of copper(II) porphyrin. Front Chem 2023; 11:1259016. [PMID: 38025061 PMCID: PMC10667454 DOI: 10.3389/fchem.2023.1259016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 10/23/2023] [Indexed: 12/01/2023] Open
Abstract
Open-shell molecules rarely fluoresce, due to their typically faster non-radiative relaxation rates compared to closed-shell ones. Even rarer is the fluorescence from states that have two more unpaired electrons than the open-shell ground state, since they involve excitations from closed-shell orbitals to vacant-shell orbitals, which are typically higher in energy compared to excitations from or out of open-shell orbitals. States that are dominated by the former type of excitations are known as tripdoublet states when they can be described as a triplet excitation antiferromagnetically coupled to a doublet state, and their description by unrestricted single-reference methods (e.g., U-TDDFT) is notoriously inaccurate due to large spin contamination. In this work, we applied our spin-adapted TDDFT method, X-TDDFT, and the efficient and accurate static-dynamic-static second order perturbation theory (SDSPT2), to the study of the excited states as well as their relaxation pathways of copper(II) porphyrin; previous experimental works suggested that the photoluminescence of some substituted copper(II) porphyrins originate from a tripdoublet state, formed by a triplet ligand π → π* excitation antiferromagnetically coupled with the unpaired d electron. Our results demonstrated favorable agreement between the X-TDDFT, SDSPT2 and experimental excitation energies, and revealed noticeable improvements of X-TDDFT compared to U-TDDFT, not only for vertical excitation energies but also for adiabatic energy differences. These suggest that X-TDDFT is a reliable tool for the study of tripdoublet state fluorescence. Intriguingly, we showed that the aforementioned tripdoublet state is only slightly above the lowest doublet excited state and lies only slightly higher than the lowest quartet state, which suggests that the tripdoublet of copper(II) porphyrin is long-lived enough to fluoresce due to a lack of efficient non-radiative relaxation pathways; an explanation for this unusual state ordering is given. Indeed, thermal vibration correlation function (TVCF)-based calculations of internal conversion, intersystem crossing, and radiative transition rates confirm that copper(II) porphyrin emits thermally activated delayed fluorescence (TADF) and a small amount of phosphorescence at low temperature (83 K), in accordance with experiment. The present contribution is concluded by a few possible approaches of designing new molecules that fluoresce from tripdoublet states.
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Affiliation(s)
- Xingwen Wang
- Qingdao Institute for Theoretical and Computational Sciences, Shandong University, Qingdao, China
| | - Chenyu Wu
- Qingdao Institute for Theoretical and Computational Sciences, Shandong University, Qingdao, China
| | - Zikuan Wang
- Qingdao Institute for Theoretical and Computational Sciences, Shandong University, Qingdao, China
- Max-Planck-Institut für Kohlenforschung, Mülheim an der Ruhr, Germany
| | - Wenjian Liu
- Qingdao Institute for Theoretical and Computational Sciences, Shandong University, Qingdao, China
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5
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Fei LR, Wang J, Bai FQ, Wang SP, Hu B, Kong CP, Zhang HX. Investigating the influence of substituent groups in TTM based radicals for the excitation process: a theoretical study. Phys Chem Chem Phys 2023; 25:25871-25879. [PMID: 37725156 DOI: 10.1039/d3cp01248d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/21/2023]
Abstract
Tri-(2,4,6-trichlorophenyl)methyl (TTM) based radicals can be promising in providing relatively high fluorescence quantum efficiency. In this study, we have evaluated the photoluminescence properties of a series of TTM-based radicals by means of DFT and TD-DFT methods. The optimized structures of the ground states (D0) and the first excited states (D1) of all the radicals are calculated and the computed emission bands are comparable with previous experimental results. knr is determined from transition dipole moments (μ12) and the energy gaps between D0 and D1 (ΔE), both of which can be regulated by the conjugated structures from the substituent groups. knr was derived from the mode-averaging method and is consistent with the experimental results. Factors influencing kr and knr, including the potential energy differences (ΔG0), the vibrational reorganization energies (λ) and the electron coupling term (Hab), are discussed. By comparing kr and knr in solvents with different polarities (cyclohexane, toluene, and chloroform), TTM based radicals in cyclohexane exhibit the most promising fluorescence efficiencies. Besides, two substituted radicals, namely 2Br-TTM-3PCz and 2F-TTM-3PCz, have been fabricated. The results show that fluorine atoms are able to increase ΔG0 and a considerably small knr has been predicted. We expect that our calculation can benefit the design of light-emitting molecules in further experiments.
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Affiliation(s)
- Lu-Ran Fei
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical, Chemistry, College of Chemistry, Jilin University, 130023 Changchun, P. R. China.
| | - Jian Wang
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical, Chemistry, College of Chemistry, Jilin University, 130023 Changchun, P. R. China.
| | - Fu-Quan Bai
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical, Chemistry, College of Chemistry, Jilin University, 130023 Changchun, P. R. China.
| | - Shi-Ping Wang
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical, Chemistry, College of Chemistry, Jilin University, 130023 Changchun, P. R. China.
| | - Bin Hu
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical, Chemistry, College of Chemistry, Jilin University, 130023 Changchun, P. R. China.
| | - Chui-Peng Kong
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical, Chemistry, College of Chemistry, Jilin University, 130023 Changchun, P. R. China.
| | - Hong-Xing Zhang
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical, Chemistry, College of Chemistry, Jilin University, 130023 Changchun, P. R. China.
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6
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Gao S, Cui Z, Li F. Doublet-emissive materials for organic light-emitting diodes: exciton formation and emission processes. Chem Soc Rev 2023; 52:2875-2885. [PMID: 37052349 DOI: 10.1039/d2cs00772j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
Doublet-emission is mainly discovered in stable radicals, lanthanide-metal complexes with an f1 electron configuration and transition-metal complexes with a low-spin d5 electron configuration, and has a distinct radiation mechanism from closed-shell luminescent molecules and thus technology opportunities. There exists an unpaired electron in the frontier molecular orbitals which enables efficient nanosecond-scale luminescence in these materials due to the spin-allowed transitions between doublet-spin states. In this review, we summarize recent advances in these materials and their application in organic light emitting diodes (OLEDs). The photoluminescence and electroluminescence mechanisms of different doublet-emissive molecular systems are discussed, in addition to the photophysical phenomena arising from doublet states. We also outline the current challenges faced by each molecular system, and the potential outlook on the future research trends in this field.
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Affiliation(s)
- Shengxiang Gao
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, P. R. China.
| | - Zhiyuan Cui
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, P. R. China.
| | - Feng Li
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, P. R. China.
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7
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Kandrashkin YE, van der Est A. A two-site triplet exciton hopping model: Application to 3P 700. J Chem Phys 2022; 157:224109. [PMID: 36546793 DOI: 10.1063/5.0132157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
A model is presented describing the effect on spin-polarized transient EPR signals caused by incoherent state hopping between two sites. It is shown that the size of the spin state space can be reduced by half to the subspace described by the site-average Hamiltonian and that the dynamics of the system results in a redistribution of the population between its eigenstates. Analytical expressions for the rates of population redistribution and the line shape are derived for the general case in which the back-and-forth rates are unequal. The EPR signals calculated using these expressions are in very good agreement with those obtained by direct numerical solution of the density matrix rate equations. The model is then used to investigate the influence of exciton hopping on triplet state transient EPR spectra. Using the triplet state of the primary donor of Photosystem I as an example, it is shown that the influence of unequal hopping rates becomes more pronounced in the spectrum at longer delay times after the laser flash.
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Affiliation(s)
- Yuri E Kandrashkin
- Zavoisky Physical-Technical Institute, FRC Kazan Scientific Center of RAS, Sibirsky Tract 10/7, Kazan 420029, Russia
| | - Art van der Est
- Department of Chemistry, Brock University, St. Catharines, Ontario L2S 3A1, Canada
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8
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Abroshan H, Winget P, Kwak HS, Brown CT, Halls MD. Organic radical emitters: nature of doublet excitons in emissive layers. Phys Chem Chem Phys 2022; 24:16891-16899. [PMID: 35788234 DOI: 10.1039/d2cp00592a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Organic radical emitters have received significant attention as a new route to efficient organic light-emitting diodes (OLEDs). The electronic structure of radical emitters allows bypassing the triplet harvesting issue in current OLED devices. However, the nature of doublet excited states remains elusive due to the complex nature of emissive layers. To date, the computational efforts have treated radical carrying materials as isolated entities in the gas phase. However, OLED materials are applied as thin solid films where intermolecular interactions significantly impact optoelectronic properties of the devices. Here, we combine molecular dynamics simulations and quantum chemical calculations to evaluate the effect of emitter-host interactions on the performance of radical-based emissive layers. Results demonstrate that intermolecular interactions remarkably modulate the electronic properties of the radicals in the thin solid films. The doublet excitons of isolated emitters demonstrate a hybrid character of charge-transfer (CT) and local-excitation (LE), while the emitter-host clusters present a significant CT character. Further, the impact of static and dynamic disorders on the hole-electron recombination is studied. Although the host-emitter interactions simultaneously decrease radiative rates and increase non-radiative rates, the latter rates are 100 times smaller than the former rates, allowing internal quantum efficiency to reach 100% for the doublet-based emission process. The results of this study highlight the significant impact of host-emitter interactions on radiative and non-radiative recombination processes and offer guidelines to tune these interactions for advancing radical-based OLEDs.
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9
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Fluorescent Organic π‐Radicals Stabilized with Boron: Featuring a SOMO–LUMO Electronic Transition. Angew Chem Int Ed Engl 2022; 61:e202201965. [DOI: 10.1002/anie.202201965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Indexed: 11/07/2022]
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10
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Green JD, Fuemmeler EG, Hele TJH. Inverse molecular design from first principles: tailoring organic chromophore spectra for optoelectronic applications. J Chem Phys 2022; 156:180901. [DOI: 10.1063/5.0082311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The discovery of molecules with tailored optoelectronic properties such as specific frequency and intensity of absorption or emission is a major challenge in creating next-generation organic light-emitting diodes (OLEDs) and photovoltaics. This raises the question: how can we predict a potential chemical structure from these properties? Approaches that attempt to tackle this inverse design problem include virtual screening, active machine learning and genetic algorithms. However, these approaches rely on a molecular database or many electronic structure calculations, and significant computational savings could be achieved if there was prior knowledge of (i) whether the optoelectronic properties of a parent molecule could easily be improved and (ii) what morphing operations on a parent molecule could improve these properties. In this perspective we address both of these challenges from first principles. We firstly adapt the Thomas-Reiche-Kuhn sum rule to organic chromophores and show how this indicates how easily the absorption and emission of a molecule can be improved. We then show how by combining electronic structure theory and intensity borrowing perturbation theory we can predict whether or not the proposed morphing operations will achieve the desired spectral alteration, and thereby derive widely-applicable design rules. We go on to provide proof-of-concept illustrations of this approach to optimizing the visible absorption of acenes and the emission of radical OLEDs. We believe this approach can be integrated into genetic algorithms by biasing morphing operations in favour of those which are likely to be successful, leading to faster molecular discovery and greener chemistry.
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11
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Ito M, Shirai S, Xie Y, Kushida T, Ando N, Soutome H, Fujimoto KJ, Yanai T, Tabata K, Miyata Y, Kita H, Yamaguchi S. Fluorescent Organic π‐Radicals Stabilized with Boron: Featuring a SOMO–LUMO Electronic Transition. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202201965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Masato Ito
- Nagoya University: Nagoya Daigaku Graduate School of Science JAPAN
| | - Shusuke Shirai
- Nagoya University: Nagoya Daigaku Graduate School of Science JAPAN
| | - Yongfa Xie
- Nagoya University: Nagoya Daigaku Graduate School of Science JAPAN
| | | | - Naoki Ando
- Nagoya University: Nagoya Daigaku Graduate School of Science JAPAN
| | - Hiroki Soutome
- Nagoya University: Nagoya Daigaku Graduate School of Science JAPAN
| | - Kazuhiro J. Fujimoto
- Nagoya University: Nagoya Daigaku Institute of Transformative Bio-Molecules JAPAN
| | - Takeshi Yanai
- Nagoya University: Nagoya Daigaku Institute of Transformative Bio-Molecules JAPAN
| | | | | | | | - Shigehiro Yamaguchi
- Nagoya University Department of Chemistry Graduate School of Science Furo, Chikusa 464-8602 Nagoya JAPAN
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12
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Zhou HP, Wu SX, Duan YC, Gao FW, Pan QQ, Kan YH, Su ZM. A theoretical study on the donor ability adjustment of tris(2,4,6-trichlorophenyl)methyl-triarylamine (TTM-TPA) radicals aiming to develop better organic luminescent materials. NEW J CHEM 2022. [DOI: 10.1039/d2nj01548j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Spin-unrestricted DFT and spin-unrestricted TDDFT calculations were performed to systematically investigate the correlation between the electron donating ability of donors and photophysical properties in D–A luminescent radicals.
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Affiliation(s)
- Hai-Ping Zhou
- Key Laboratory of Electrochemical Energy Storage and Energy Conversion of Hainan Province, School of Chemistry & Chemical Engineering, Hainan Normal University, Haikou 571158, China
- School of Chemistry and Environmental Engineering, Jilin Provincial Science and Technology Innovation Center of Optical Materials and Chemistry, Changchun University of Science and Technology, 7989 Weixing Road, Changchun 130012, China
| | - Shui-Xing Wu
- Key Laboratory of Electrochemical Energy Storage and Energy Conversion of Hainan Province, School of Chemistry & Chemical Engineering, Hainan Normal University, Haikou 571158, China
| | - Ying-Chen Duan
- School of Chemistry and Environmental Engineering, Jilin Provincial Science and Technology Innovation Center of Optical Materials and Chemistry, Changchun University of Science and Technology, 7989 Weixing Road, Changchun 130012, China
| | - Feng-Wei Gao
- School of Chemistry and Environmental Engineering, Jilin Provincial Science and Technology Innovation Center of Optical Materials and Chemistry, Changchun University of Science and Technology, 7989 Weixing Road, Changchun 130012, China
| | - Qing-Qing Pan
- School of Chemistry and Environmental Engineering, Jilin Provincial Science and Technology Innovation Center of Optical Materials and Chemistry, Changchun University of Science and Technology, 7989 Weixing Road, Changchun 130012, China
| | - Yu-He Kan
- Jiangsu Province Key Laboratory for Chemistry of Low-Dimensional Materials, School of Chemistry and Chemical Engineering, Huaiyin Normal University, Huai'an 223300, China
| | - Zhong-Min Su
- School of Chemistry and Environmental Engineering, Jilin Provincial Science and Technology Innovation Center of Optical Materials and Chemistry, Changchun University of Science and Technology, 7989 Weixing Road, Changchun 130012, China
- Institute of Functional Material Chemistry, Faculty of Chemistry & National & Local United Engineering Laboratory for Power Battery, Northeast Normal University, Changchun 130024, China
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13
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Zhou HP, Wu SX, Duan YC, Gao FW, Pan QQ, Kan YH, Su ZM. The combination of skeleton-engineering and periphery-engineering: a design strategy for organic doublet emitters. Phys Chem Chem Phys 2022; 24:26853-26862. [DOI: 10.1039/d2cp03948f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A series of radicals based on tris(2,4,6-trichlorophenyl)methyl (TTM) were theoretically designed and evaluated by combining skeleton-engineering and periphery-engineering strategies.
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Affiliation(s)
- Hai-Ping Zhou
- School of Chemistry and Environmental Engineering, Jilin Provincial Science and Technology Innovation Center of Optical Materials and Chemistry, Changchun University of Science and Technology, Changchun 130012, China
| | - Shui-Xing Wu
- Key Laboratory of Electrochemical Energy Storage and Energy Conversion of Hainan Province, School of Chemistry & Chemical Engineering, Hainan Normal University, Haikou 571158, China
| | - Ying-Chen Duan
- School of Chemistry and Environmental Engineering, Jilin Provincial Science and Technology Innovation Center of Optical Materials and Chemistry, Changchun University of Science and Technology, Changchun 130012, China
| | - Feng-Wei Gao
- School of Chemistry and Environmental Engineering, Jilin Provincial Science and Technology Innovation Center of Optical Materials and Chemistry, Changchun University of Science and Technology, Changchun 130012, China
| | - Qing-Qing Pan
- School of Chemistry and Environmental Engineering, Jilin Provincial Science and Technology Innovation Center of Optical Materials and Chemistry, Changchun University of Science and Technology, Changchun 130012, China
| | - Yu-He Kan
- Jiangsu Province Key Laboratory for Chemistry of Low-Dimensional Materials, School of Chemistry and Chemical Engineering, Huaiyin Normal University, Huai’an 223300, China
| | - Zhong-Min Su
- School of Chemistry and Environmental Engineering, Jilin Provincial Science and Technology Innovation Center of Optical Materials and Chemistry, Changchun University of Science and Technology, Changchun 130012, China
- State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130021, China
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14
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Witwicki M, Lewińska A, Ozarowski A. o-Semiquinone radical anion isolated as an amorphous porous solid. Phys Chem Chem Phys 2021; 23:17408-17419. [PMID: 34351330 DOI: 10.1039/d1cp01596f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The use of metal cations is a commonly applied strategy to create S > 1/2 stable molecular systems containing semiquinone radicals. Persistent mono-semiquinonato complexes of diamagnetic metal ions (S = 1/2) have been hitherto less common and mostly limited to the complexes of heavy metal ions. In this work, a mono-semiquinonato complex of aluminum, derived from 1,2-dihydroxybenzene, is obtained using a surprisingly short and uncomplicated procedure. The isolated product is an amorphous and porous solid that exhibits very good stability under ambient conditions. To characterise its molecular and electronic structure, 9.7, 34 and 406 GHz EPR spectroscopy was used in concert with computational techniques (DFT and DLPNO-CCSD). It was revealed that the radical complex is composed of two chemically equivalent aluminum cations and two catechol-like ligands with the unpaired electron uniformly distributed between the two organic molecules. The good stability and porous structure make this complex applicable in heterogeneous aerobic reactions.
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Affiliation(s)
- Maciej Witwicki
- Faculty of Chemistry, Wroclaw University, Joliot-Curie 14, 50-383 Wroclaw, Poland.
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15
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Kandrashkin YE, van der Est A. Enhanced Intersystem Crossing due to Resonant Energy Transfer to a Remote Spin. J Phys Chem Lett 2021; 12:7312-7318. [PMID: 34319743 DOI: 10.1021/acs.jpclett.1c02032] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
A new mechanism for enhanced intersystem crossing in coupled three-spin systems consisting of a chromophore and an attached radical is proposed. It is shown that if the unpaired electron of the radical experiences spin-orbit coupling and different exchange interactions with the two unpaired electron spins of the chromophore, energy transfer from the chromophore to the radical can occur together with singlet-triplet intersystem crossing in the chromophore. The efficiency of this process increases dramatically when the electronic excitation of the radical is resonant with the S1-T1 energy gap of the chromophore. The types of systems in which this resonance could be achieved are discussed, and it is suggested that the mechanism could result in improved sensitization in near-IR emitting lanthanide dyes.
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Affiliation(s)
- Yuri E Kandrashkin
- Zavoisky Physical-Technical Institute, FRC Kazan Scientific Center of RAS, Kazan 420029, Russian Federation
| | - Art van der Est
- Department of Chemistry Brock University, St. Catharines, ON L2S 3A1, Canada
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16
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Dhali R, Phan Huu DKA, Terenziani F, Sissa C, Painelli A. Thermally activated delayed fluorescence: A critical assessment of environmental effects on the singlet-triplet energy gap. J Chem Phys 2021; 154:134112. [PMID: 33832272 DOI: 10.1063/5.0042058] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The effective design of dyes optimized for thermally activated delayed fluorescence (TADF) requires the precise control of two tiny energies: the singlet-triplet gap, which has to be maintained within thermal energy, and the strength of spin-orbit coupling. A subtle interplay among low-energy excited states having dominant charge-transfer and local character then governs TADF efficiency, making models for environmental effects both crucial and challenging. The main message of this paper is a warning to the community of chemists, physicists, and material scientists working in the field: the adiabatic approximation implicitly imposed to the treatment of fast environmental degrees of freedom in quantum-classical and continuum solvation models leads to uncontrolled results. Several approximation schemes were proposed to mitigate the issue, but we underline that the adiabatic approximation to fast solvation is inadequate and cannot be improved; rather, it must be abandoned in favor of an antiadiabatic approach.
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Affiliation(s)
- Rama Dhali
- Department of Chemistry, Life Science and Environmental Sustainability, University of Parma, Parma, Italy
| | - D K Andrea Phan Huu
- Department of Chemistry, Life Science and Environmental Sustainability, University of Parma, Parma, Italy
| | - Francesca Terenziani
- Department of Chemistry, Life Science and Environmental Sustainability, University of Parma, Parma, Italy
| | - Cristina Sissa
- Department of Chemistry, Life Science and Environmental Sustainability, University of Parma, Parma, Italy
| | - Anna Painelli
- Department of Chemistry, Life Science and Environmental Sustainability, University of Parma, Parma, Italy
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17
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Ma L, Feng W, Shang H, Lin X, Xi Y. Tunable photochemical 6π heterocyclization reactions mediated by a boron Lewis acid. NEW J CHEM 2021. [DOI: 10.1039/d1nj03218f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The regulation effect of boron Lewis acid catalyst on the photoinduced 6π heterocyclization was investigated by using multi-configurational ab initio calculations.
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Affiliation(s)
- Lishuang Ma
- Department of Chemistry, College of Science, China University of Petroleum (East China), Qingdao, 266580, P. R. China
| | - Wenxu Feng
- Department of Chemistry, College of Science, China University of Petroleum (East China), Qingdao, 266580, P. R. China
| | - Hongyan Shang
- Department of Chemistry, College of Science, China University of Petroleum (East China), Qingdao, 266580, P. R. China
- State Key Laboratory of Heavy Oil Processing China University of Petroleum (East China), Qingdao, 266580, P. R. China
| | - Xufeng Lin
- Department of Chemistry, College of Science, China University of Petroleum (East China), Qingdao, 266580, P. R. China
| | - Yanyan Xi
- State Key Laboratory of Heavy Oil Processing China University of Petroleum (East China), Qingdao, 266580, P. R. China
- College of Chemical Engineering, China University of Petroleum (East China), Qingdao, 266580, P. R. China
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18
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Abdurahman A, Hele TJH, Gu Q, Zhang J, Peng Q, Zhang M, Friend RH, Li F, Evans EW. Understanding the luminescent nature of organic radicals for efficient doublet emitters and pure-red light-emitting diodes. NATURE MATERIALS 2020; 19:1224-1229. [PMID: 32541936 DOI: 10.1038/s41563-020-0705-9] [Citation(s) in RCA: 115] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 05/11/2020] [Indexed: 06/11/2023]
Abstract
The doublet-spin nature of radical emitters is advantageous for applications in organic light-emitting diodes, as it avoids the formation of triplet excitons that limit the electroluminescence efficiency of non-radical emitters. However, radicals generally show low optical absorption and photoluminescence yields. Here we explain the poor optical properties of radicals based on alternant hydrocarbons, and establish design rules to increase the absorption and luminescence yields for donor-acceptor-type radicals. We show that non-alternant systems are necessary to lift the degeneracy of the lowest energy orbital excitations; moreover, intensity borrowing from an intense high-lying transition by the low-energy charge-transfer excitation enhances the oscillator strength of the emitter. We apply these rules to design tris(2,4,6-trichlorophenyl)methyl-pyridoindolyl derivatives with a high photoluminescence quantum yield (>90%). Organic light-emitting diodes based on these molecules showed a pure-red emission with an over 12% external quantum efficiency. These insights may be beneficial for the rational design and discovery of highly luminescent doublet emitters.
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Affiliation(s)
- Alim Abdurahman
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, P. R. China
| | | | - Qinying Gu
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
| | - Jiangbin Zhang
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
| | - Qiming Peng
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, P. R. China
- Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing, P. R. China
| | - Ming Zhang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, P. R. China
| | | | - Feng Li
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, P. R. China.
- Cavendish Laboratory, University of Cambridge, Cambridge, UK.
| | - Emrys W Evans
- Cavendish Laboratory, University of Cambridge, Cambridge, UK.
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19
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Wang Z, Li Z, Zhang Y, Liu W. Analytic energy gradients of spin-adapted open-shell time-dependent density functional theory. J Chem Phys 2020; 153:164109. [DOI: 10.1063/5.0025428] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Affiliation(s)
- Zikuan Wang
- Beijing National Laboratory for Molecular Sciences, Institute of Theoretical and Computational Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, People’s Republic of China
- Qingdao Institute for Theoretical and Computational Sciences, Shandong University, Qingdao, Shandong 266237, People’s Republic of China
| | - Zhendong Li
- Key Laboratory of Theoretical and Computational Photochemistry of Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, People’s Republic of China
| | - Yong Zhang
- Qingdao Institute for Theoretical and Computational Sciences, Shandong University, Qingdao, Shandong 266237, People’s Republic of China
| | - Wenjian Liu
- Qingdao Institute for Theoretical and Computational Sciences, Shandong University, Qingdao, Shandong 266237, People’s Republic of China
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20
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Wang XQ, Wang W, Peng M, Zhang XZ. Free radicals for cancer theranostics. Biomaterials 2020; 266:120474. [PMID: 33125969 DOI: 10.1016/j.biomaterials.2020.120474] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 09/20/2020] [Accepted: 10/18/2020] [Indexed: 01/06/2023]
Abstract
Free radicals were generally regarded as highly reactive, transient and harmful species. In fact, some of the free radicals can also be inactive, long-lived and beneficial for our health. These properties of free radicals provide future possibilities for their application in various fields. Owning to their open-shell electronic structure, free radicals exhibit unique advantages in biomedical applications, such as high reactivity, photoacoustic and photothermal conversion ability, molecular magnetic. In this review, recent progress on free radicals and their applications in cancer theranostics are presented. Typical materials that exhibit controlled generation of free radicals and their applications for photodynamic therapy (PDT), chemodynamic therapy (CDT), sonodynamic therapy (SDT), gas therapy, hypoxic cancer treatment, photothermal therapy (PTT), photoacoustic imaging (PAI) and magnetic resonance imaging (MRI) are summarized and discussed.
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Affiliation(s)
- Xiao-Qiang Wang
- Key Laboratory of Biomedical Polymers of Ministry of Education & Department of Chemistry, Wuhan University, Wuhan, 430072, PR China; The State Key Laboratory of Refractories and Metallurgy, School of Chemistry and Chemical Engineering, Wuhan University of Science and Technology, Wuhan, 430081, PR China
| | - Wenjing Wang
- The State Key Laboratory of Refractories and Metallurgy, School of Chemistry and Chemical Engineering, Wuhan University of Science and Technology, Wuhan, 430081, PR China
| | - Mengyun Peng
- Key Laboratory of Biomedical Polymers of Ministry of Education & Department of Chemistry, Wuhan University, Wuhan, 430072, PR China; School of Pharmacy, Zhejiang Chinese Medical University, Hangzhou, 310000, PR China
| | - Xian-Zheng Zhang
- Key Laboratory of Biomedical Polymers of Ministry of Education & Department of Chemistry, Wuhan University, Wuhan, 430072, PR China.
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21
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Wehrmann CM, Imran M, Pointer C, Fredin LA, Young ER, Chen MS. Spin multiplicity effects in doublet versus singlet emission: the photophysical consequences of a single electron. Chem Sci 2020; 11:10212-10219. [PMID: 34094286 PMCID: PMC8162447 DOI: 10.1039/d0sc04211k] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Ambient-stable fluorescent radicals have recently emerged as promising luminescent materials; however, tailoring their properties has been difficult due to the limited photophysical understanding of open-shell organic systems. Here we report the experimental and computational analysis of a redox pair of π-conjugated fluorescent molecules that differ by one electron. A π-dication (DC) and π-radical cation (RC) demonstrate different absorption spectra, but similar red emission (λemiss,max = ∼630 nm), excitation maxima (λexc,max = ∼530 nm), fluorescence lifetimes (1–10 ns), and even excited-state (non-emissive) lifetimes when measured by transient absorption spectroscopy. Despite their experimental similarities, time-dependent density functional theory (TDDFT) studies reveal that DC and RC emission mechanisms are distinct and rely on different electronic transitions. Excited-state reorganization occurs by hole relaxation in singlet DC, while doublet RC undergoes a Jahn-Teller distortion by bending its π-backbone in order to facilitate spin-pairing between singly occupied molecular orbitals. This relationship between the excited-state dynamics of RC and its π-backbone geometry illustrates a potential strategy for developing π-conjugated radicals with new emission properties. Additionally, by comparing TDDFT and CIS (configuration interaction singles) excitations, we show that unrestricted TDDFT accurately reproduces experimental absorption spectra and provides an opportunity to examine the relaxed excited-state properties of large open-shell molecules like RC. Experimental and computational studies reveal mechanistic differences in the photophysics of an open- versus closed-shell π-conjugated redox pair.![]()
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Affiliation(s)
- Caleb M Wehrmann
- Department of Chemistry, Lehigh University Bethlehem PA 18015 USA
| | - Muhammad Imran
- Department of Chemistry, Lehigh University Bethlehem PA 18015 USA
| | - Craig Pointer
- Department of Chemistry, Lehigh University Bethlehem PA 18015 USA
| | - Lisa A Fredin
- Department of Chemistry, Lehigh University Bethlehem PA 18015 USA
| | | | - Mark S Chen
- Department of Chemistry, Lehigh University Bethlehem PA 18015 USA
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22
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Zeng J, Qiu SB, Zhao YJ, Yang XB, Yao Y. Quantum Dynamics Simulation of Doublet Excitation and Magnetic Field Effect in Neutral Radical Materials. J Phys Chem Lett 2020; 11:1194-1198. [PMID: 31967832 DOI: 10.1021/acs.jpclett.9b03635] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The photon absorption and the relevant magnetic field effect of a doublet in neutral radical materials are investigated by combining the density functional theory and the variational quantum dynamics with Davydov ansatz. The doublet is a perfect model system to study the full-quantum dynamics of a two-level system coupling to a realistic molecular vibrational environment. In this work, we simulate the optical absorption spectroscopy of the neutral radical material, (4-N-carbazolyl-2,6-dichlorophenyl)bis(2,4,6-trichlorophenyl)-methyl, and find a good agreement with experiments for both highest occupied molecular orbital-singly occupied molecular orbital (SOMO) and SOMO-lowest unoccupied molecular orbital transitions. The nontrivial role of the intramolecular vibronic couplings is comprehensively discussed with separate spectroscopy and population dynamics, suggesting different contributions and the long time scale effect stemming from the vibrations, according to different symmetries. On the basis of the model, an applied magnetic field is taken into account to qualitatively investigate its magnetic properties in a dynamics manner, leading to a result which can be described by a sum of Lorentzian functions.
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Affiliation(s)
- Jiarui Zeng
- Department of Physics , South China University of Technology , Guangzhou 510640 , China
| | - Shao-Bin Qiu
- Department of Physics , South China University of Technology , Guangzhou 510640 , China
| | - Yu-Jun Zhao
- Department of Physics , South China University of Technology , Guangzhou 510640 , China
| | - Xiao-Bao Yang
- Department of Physics , South China University of Technology , Guangzhou 510640 , China
| | - Yao Yao
- Department of Physics , South China University of Technology , Guangzhou 510640 , China
- State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , China
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23
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Solid-state fluorescence of two zinc coordination polymers from bulky dicyano-phenylenevinylene and bis-azobenzene cores. INORG CHEM COMMUN 2019. [DOI: 10.1016/j.inoche.2019.107602] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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24
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Lo YC, Yeh TH, Wang CK, Peng BJ, Hsieh JL, Lee CC, Liu SW, Wong KT. High-Efficiency Red and Near-Infrared Organic Light-Emitting Diodes Enabled by Pure Organic Fluorescent Emitters and an Exciplex-Forming Cohost. ACS APPLIED MATERIALS & INTERFACES 2019; 11:23417-23427. [PMID: 31252481 DOI: 10.1021/acsami.9b06612] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Three D-A-D-configured molecules DTPBT, DTPNT, and DTPNBT with high quantum yield of orange red (628 nm), red (659 nm), and deep-red/NIR (710 nm) fluorescence, respectively, were developed as emitting dopants in an exciplex-forming cohost (TCTA:3P-T2T) for high-efficiency fluorescence-based organic light-emitting diodes (OLEDs). The obtained physical properties together with theoretical calculations analyzed from these new molecules establish a clear structure-property relationship, in which the feature of central acceptor 2,1,3-benzothiadiazole (BT), naphtho[1,2-c:5,6-c']bis[1,2,5]thiadiazole (NT), and 2,1,3-naphthothiadiazole (NBT) plays the crucial role for governing the physical characteristics. The optimized device configured as ITO/HAT-CN/TAPC/TCTA/TCTA:3P-T2T:5% emitter/3P-T2T/LiF/Al gave a record-high efficiency of orange red (591 nm, 15%), red (647 nm, 10%), and deep-red/NIR (689 nm, 9%) electroluminescent devices. The effective harvest of triplet excitons with an exciplex-forming system in conjunction with efficient energy transfer between the exciplex and the dopant is beneficial for such high device efficiencies. More importantly, the stable exciplex-forming cohost and fast radiative decay rate of DTPNT render this particular device exhibiting high device stability as indicated by the low efficiency roll-off under high current densities (EQE (external quantum efficiency) values of 8.1% at 1000 cd m-2 and 6.8% at 10,000 cd m-2). These results reveal the potential of employing an exciplex-forming system as cohost for fluorescent dopants to furnish high-efficiency OLEDs with an emission wavelength extending to the red or even the NIR range.
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Affiliation(s)
- Yuan-Chih Lo
- Department of Chemistry , National Taiwan University , Taipei 10617 , Taiwan
| | - Tzu-Hung Yeh
- Department of Electronic Engineering , National Taiwan University of Science and Technology , Taipei 10617 , Taiwan
| | - Chun-Kai Wang
- Department of Chemistry , National Taiwan University , Taipei 10617 , Taiwan
| | - Bo-Ji Peng
- Department of Chemistry , National Taiwan University , Taipei 10617 , Taiwan
| | - Jing-Lin Hsieh
- Department of Electronic Engineering , National Taiwan University of Science and Technology , Taipei 10617 , Taiwan
| | - Chih-Chien Lee
- Department of Electronic Engineering , National Taiwan University of Science and Technology , Taipei 10617 , Taiwan
| | | | - Ken-Tsung Wong
- Department of Chemistry , National Taiwan University , Taipei 10617 , Taiwan
- Institute of Atomic and Molecular Science , Academia Sinica , Taipei 10617 , Taiwan
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