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Zhang K, Zhou Z, Liu D, Chen Y, Zhang S, Pan J, Qiao X, Ma D, Su S, Zhu W, Liu Y. Boosting External Quantum Efficiency to 12.0 % of an Ultraviolet OLED by Engineering the Horizontal Dipole Orientation of a Hot Exciton Emitter. Angew Chem Int Ed Engl 2024; 63:e202407502. [PMID: 38721850 DOI: 10.1002/anie.202407502] [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: 04/19/2024] [Indexed: 06/27/2024]
Abstract
Currently, much research effort has been devoted to improving the exciton utilization efficiency and narrowing the emission spectra of ultraviolet (UV) fluorophores for organic light-emitting diode (OLED) applications, while almost no attention has been paid to optimizing their light out-coupling efficiency. Here, we developed a linear donor-acceptor-donor (D-A-D) triad, namely CDFDB, which possesses high-lying reverse intersystem crossing (hRISC) property. Thanks to its integrated narrowband UV photoluminescence (PL) (λPL: 397 nm; FWHM: 48 nm), moderate PL quantum yield (ϕPL: 72 %, Tol), good triplet hot exciton (HE) conversion capability, and large horizontal dipole ratio (Θ//: 92 %), the OLEDs based on CDFDB not only can emit UV electroluminescence with relatively good color purity (λEL: 398 nm; CIEx,y: 0.161, 0.040), but also show a record maximum external quantum efficiency (EQEmax) of 12.0 %. This study highlights the important role of horizontal dipole orientation engineering in the molecular design of HE UV-OLED fluorophores.
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Affiliation(s)
- Kai Zhang
- School of Materials Science and Engineering, Jiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and Applications, Changzhou University, Changzhou, 213164, P. R. China
| | - Zhongxin Zhou
- School of Materials Science and Engineering, Jiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and Applications, Changzhou University, Changzhou, 213164, P. R. China
| | - Denghui Liu
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Yichao Chen
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Shiyue Zhang
- School of Materials Science and Engineering, Jiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and Applications, Changzhou University, Changzhou, 213164, P. R. China
| | - Jie Pan
- School of Materials Science and Engineering, Jiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and Applications, Changzhou University, Changzhou, 213164, P. R. China
| | - Xianfeng Qiao
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Dongge Ma
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - ShiJian Su
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Weiguo Zhu
- School of Materials Science and Engineering, Jiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and Applications, Changzhou University, Changzhou, 213164, P. R. China
| | - Yu Liu
- School of Materials Science and Engineering, Jiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and Applications, Changzhou University, Changzhou, 213164, P. R. China
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2
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Haensch VG, Hertweck C. Photosensitizers Enable the Formation of Biphenyls with UV-LEDs and Sunlight. Chemistry 2024; 30:e202400605. [PMID: 38421111 DOI: 10.1002/chem.202400605] [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: 02/14/2024] [Revised: 02/28/2024] [Accepted: 02/29/2024] [Indexed: 03/02/2024]
Abstract
The regioselective synthesis of biphenyls, which are economically important pharmaceuticals, agrochemicals, and liquid crystals, is a challenging task. Current methods rely on metal-dependent cross-coupling reactions, which unfortunately require the use of harmful halogenated aryls and heavy metal catalysts that are toxic and difficult to remove from the final products. Recently, we have circumvented these problems by developing a metal-free and broadly applicable photochemical method for biphenyl synthesis using UV-C light, called photosplicing. Here we present an improved method using photosensitizers in combination with UV-B, UV-A light, or sunlight. Using a high-precision flow reactor with deep-UV LEDs, we investigated the ability of commonly available organic photosensitizers to enhance the photosplicing reaction and identified a number of suitable photosensitizers with the required triplet energy. This method allows for easy batch synthesis of biaryls in borosilicate glassware and paves the way for their large-scale production without the need for flow reactors.
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Affiliation(s)
- Veit G Haensch
- Department of Biomolecular Chemistry Leibniz Institute for Natural Product Research and Infection Biology, HKI, Beutenbergstrasse 11a, 07745, Jena, Germany
| | - Christian Hertweck
- Department of Biomolecular Chemistry Leibniz Institute for Natural Product Research and Infection Biology, HKI, Beutenbergstrasse 11a, 07745, Jena, Germany
- Friedrich Schiller University Jena, 07743, Jena, Germany
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3
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Rehpenn A, Hindelang S, Truong KN, Pöthig A, Storch G. Enhancing Flavins Photochemical Activity in Hydrogen Atom Abstraction and Triplet Sensitization through Ring-Contraction. Angew Chem Int Ed Engl 2024; 63:e202318590. [PMID: 38339882 DOI: 10.1002/anie.202318590] [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: 12/04/2023] [Revised: 01/30/2024] [Accepted: 02/01/2024] [Indexed: 02/12/2024]
Abstract
The isoalloxazine heterocycle of flavin cofactors reacts with various nucleophiles to form covalent adducts with important functions in enzymes. Molecular flavin models allow for the characterization of such adducts and the study of their properties. A fascinating set of reactions occurs when flavins react with hydroxide base, which leads to imidazolonequinoxalines, ring-contracted flavins, with so far unexplored activity. We report a systematic study of the photophysical properties of this new chromophore by absorption and emission spectroscopy as well as cyclic voltammetry. Excited, ring-contracted flavins are significantly stronger hydrogen atom abstractors when compared to the parent flavins, which allowed the direct trifluoromethylthiolation of aliphatic methine positions (bond dissociation energy (BDE) of 400.8 kJ mol-1). In an orthogonal activity, their increased triplet energy (E(S0←T1)=244 kJ mol-1) made sensitized reactions possible which exceeded the power of standard flavins. Combining both properties, ring-contracted flavin catalysts enabled the one-pot, five-step transformation of α-tropolone into trans-3,4-disubstituted cyclopentanones. We envision this new class of flavin-derived chromophores to open up new modes of reactivity that are currently impossible with unmodified flavins.
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Affiliation(s)
- Andreas Rehpenn
- Technical University of Munich (TUM), School of Natural Sciences and Catalysis Research Center (CRC), Lichtenbergstr. 4, 85747, Garching, Germany
| | - Stephan Hindelang
- Technical University of Munich (TUM), School of Natural Sciences and Catalysis Research Center (CRC), Lichtenbergstr. 4, 85747, Garching, Germany
| | - Khai-Nghi Truong
- Rigaku Europe SE, Hugenottenallee 167, 63263, Neu-Isenburg, Germany
| | - Alexander Pöthig
- Technical University of Munich (TUM), School of Natural Sciences and Catalysis Research Center (CRC), Lichtenbergstr. 4, 85747, Garching, Germany
| | - Golo Storch
- Technical University of Munich (TUM), School of Natural Sciences and Catalysis Research Center (CRC), Lichtenbergstr. 4, 85747, Garching, Germany
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Sudarkova SM, Khinevich VE, Ioffe IN, Quick M, Kovalenko SA. Substitution pattern dependent behavior of the singlet excited states in symmetrically fluorinated biphenyls. Phys Chem Chem Phys 2021; 23:22067-22077. [PMID: 34570141 DOI: 10.1039/d1cp03560f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Biphenyls are important basic chromophore systems that offer a possibility to study the effects of chemical substitution on the lower-lying excited states without complications from photoisomerization or other side processes. For several symmetric biphenyls, pristine biphenyl (bP0), 4,4'-difluorobiphenyl (bP2), 2,3,5,6,2',3',5',6'-octafluorobiphenyl (bP8), and perfluorobiphenyl (bP10), we report stationary and ultrafast solution-phase spectra rationalized with the aid of computations by means of the XMCQDPT2 multi-configuration perturbation theory and TDDFT. Polyfluorination tends to broaden the gap between the nearly degenerate S1 + S2 pair of states and the S3 state in bP8 and bP10, yet relaxation from any sheet of the S1-S3 manifold leads through a system of state crossings to the same stationary points in S1. Unlike bP0 and bP2 where the relaxed excited state is planar and non-polar, excited bP8 and bP10 exhibit sudden polarization to give a symmetry-lowered excited state via pseudo-Jahn-Teller interactions involving S1 and S2. Of particular interest is excited bP10 which reveals both sudden polarization and loss of planarity of one phenyl ring. We also demonstrate the unsatisfactory performance of the TDDFT methodology as applied to the biphenyls.
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Affiliation(s)
- Svetlana M Sudarkova
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia.
| | - Victor E Khinevich
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia.
| | - Ilya N Ioffe
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia.
| | - M Quick
- Department of Chemistry, Humboldt-Universität zu Berlin, Berlin 12489, Germany.
| | - Sergey A Kovalenko
- Department of Chemistry, Humboldt-Universität zu Berlin, Berlin 12489, Germany.
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The Photophysical Properties of Triisopropylsilyl-ethynylpentacene—A Molecule with an Unusually Large Singlet-Triplet Energy Gap—In Solution and Solid Phases. CHEMISTRY-SWITZERLAND 2020. [DOI: 10.3390/chemistry2020033] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The process of singlet-exciton fission (SEF) has attracted much attention of late. One of the most popular SEF compounds is TIPS-pentacene (TIPS-P, where TIPS = triisopropylsilylethynyl) but, despite its extensive use as both a reference and building block, its photophysical properties are not so well established. In particular, the triplet state excitation energy remains uncertain. Here, we report quantitative data and spectral characterization for excited-singlet and -triplet states in dilute solution. The triplet energy is determined to be 7940 ± 1200 cm−1 on the basis of sensitization studies using time-resolved photoacoustic calorimetry. The triplet quantum yield at the limit of low concentration and low laser intensity is only ca. 1%. Self-quenching occurs at high solute concentration where the fluorescence yield and lifetime decrease markedly relative to dilute solution but we were unable to detect excimer emission by steady-state spectroscopy. Short-lived fluorescence, free from excimer emission or phosphorescence, occurs for crystals of TIPS-P, most likely from amorphous domains.
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Sugino H, Koyama Y, Nakano T. A high triplet-energy polymer: synthesis and photo-physical properties of a π-stacked vinyl polymer having a xanthone moiety in the side chain. RSC Adv 2015. [DOI: 10.1039/c4ra16023a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Poly(xanthon-3-yl methacrylate) having a π-stacked conformation efficiently harvests photo excitation energy for sky blue phosphorescent emission of iridium bis[(4,6-difluorophenyl)pyridinato-N,C2]picolinate (FIrpic) in solution and in film.
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Affiliation(s)
- Hiroyoshi Sugino
- Catalysis Research Center (CRC)
- Hokkaido University
- Sapporo 001-0021
- Japan
| | - Yasuhito Koyama
- Catalysis Research Center (CRC)
- Hokkaido University
- Sapporo 001-0021
- Japan
| | - Tamaki Nakano
- Catalysis Research Center (CRC)
- Hokkaido University
- Sapporo 001-0021
- Japan
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Li X, Bird M, Mauro G, Asaoka S, Cook AR, Chen HC, Miller JR. Transport of Triplet Excitons along Continuous 100 nm Polyfluorene Chains. J Phys Chem B 2014; 119:7210-8. [DOI: 10.1021/jp509396s] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Xiang Li
- Chemistry
Department, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Matthew Bird
- Chemistry
Department, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Gina Mauro
- Chemistry
Department, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Sadayuki Asaoka
- Department
of Biomolecular Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Andrew R. Cook
- Chemistry
Department, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Hung-Cheng Chen
- Chemistry
Department, Brookhaven National Laboratory, Upton, New York 11973, United States
- Department
of Materials Science and Engineering, Stony Brook University, Stony Brook, New York 11790, United States
| | - John R. Miller
- Chemistry
Department, Brookhaven National Laboratory, Upton, New York 11973, United States
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Fan C, Zhao F, Gan P, Yang S, Liu T, Zhong C, Ma D, Qin J, Yang C. Simple Bipolar Molecules Constructed from Biphenyl Moieties as Host Materials for Deep-Blue Phosphorescent Organic Light-Emitting Diodes. Chemistry 2012; 18:5510-4. [DOI: 10.1002/chem.201103703] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Indexed: 11/06/2022]
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9
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Yoon ZS, Chan YT, Li S, Newkome GR, Goodson T. Ultrafast Time-Resolved Spectroscopy of Self-Assembled Cyclic Fe(II)−Bisterpyridine Complexes. J Phys Chem B 2010; 114:11731-6. [DOI: 10.1021/jp104836k] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zin Seok Yoon
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, and Department of Chemistry, University of Akron, Akron, Ohio 44325
| | - Yi-Tsu Chan
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, and Department of Chemistry, University of Akron, Akron, Ohio 44325
| | - Sinan Li
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, and Department of Chemistry, University of Akron, Akron, Ohio 44325
| | - George R. Newkome
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, and Department of Chemistry, University of Akron, Akron, Ohio 44325
| | - Theodore Goodson
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, and Department of Chemistry, University of Akron, Akron, Ohio 44325
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11
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Seixas de Melo JS, Burrows HD, Serpa C, Arnaut LG. The Triplet State of Indigo. Angew Chem Int Ed Engl 2007; 46:2094-6. [PMID: 17299823 DOI: 10.1002/anie.200604679] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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