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Zhao H, Kim J, Ding K, Jung M, Li Y, Ade H, Lee JY, Forrest SR. Control of Host-Matrix Morphology Enables Efficient Deep-Blue Organic Light-Emitting Devices. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2210794. [PMID: 36638153 DOI: 10.1002/adma.202210794] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 12/22/2022] [Indexed: 06/17/2023]
Abstract
Mixing a sterically bulky, electron-transporting host material into a conventional single host-guest emissive layer is demonstrated to suppress phase separation of the host matrix while increasing the efficiency and operational lifetime of deep-blue phosphorescent organic light-emitting diodes (PHOLEDs) with chromaticity coordinates of (0.14, 0.15). The bulky host enables homogenous mixing of the molecules comprising the emissive layer while suppressing single host aggregation; a significant loss channel of nonradiative recombination. By controlling the amorphous phase of the host-matrix morphology, the mixed-host device achieves a significant reduction in nonradiative exciton decay, resulting in 120 ± 6% increase in external quantum efficiency relative to an analogous, single-host device. In contrast to single host PHOLEDs where electrons are transported by the host and holes by the dopants, both charge carriers are conducted by the mixed host, reducing the probability of exciton annihilation, thereby doubling of the deep-blue PHOLED operational lifetime. These findings demonstrate that the host matrix morphology affects almost every aspect of PHOLED performance.
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Affiliation(s)
- Haonan Zhao
- Department of Physics, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Jongchan Kim
- Department of Electrical and Computer Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Kan Ding
- Department of Physics, North Carolina State University, Raleigh, NC, 27695, USA
| | - Mina Jung
- School of Chemical Engineering, Sungkyunkwan University, Suwon, Gyeonggi, 03063, Republic of Korea
| | - Yongxi Li
- Department of Physics, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Harald Ade
- Department of Physics, North Carolina State University, Raleigh, NC, 27695, USA
| | - Jun Yeob Lee
- School of Chemical Engineering, Sungkyunkwan University, Suwon, Gyeonggi, 03063, Republic of Korea
| | - Stephen R Forrest
- Department of Physics, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Electrical and Computer Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
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Abstract
Harnessing cost-efficient printable semiconductor materials as near-infrared (NIR) emitters in light-emitting diodes (LEDs) is extremely attractive for sensing and diagnostics, telecommunications, and biomedical sciences. However, the most efficient NIR LEDs suitable for printable electronics rely on emissive materials containing precious transition metal ions (such as platinum), which have triggered concerns about their poor biocompatibility and sustainability. Here, we review and highlight the latest progress in NIR LEDs based on non-toxic and low-cost functional materials suitable for solution-processing deposition. Different approaches to achieve NIR emission from organic and hybrid materials are discussed, with particular focus on fluorescent and exciplex-forming host-guest systems, thermally activated delayed fluorescent molecules, aggregation-induced emission fluorophores, as well as lead-free perovskites. Alternative strategies leveraging photonic microcavity effects and surface plasmon resonances to enhance the emission of such materials in the NIR are also presented. Finally, an outlook for critical challenges and opportunities of non-toxic NIR LEDs is provided.
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Affiliation(s)
- Kunping Guo
- Department of Physics and Astronomy and London Centre for Nanotechnology, University College London, London WC1E 6BT, UK
| | - Marcello Righetto
- Department of Physics and Astronomy and London Centre for Nanotechnology, University College London, London WC1E 6BT, UK
| | - Alessandro Minotto
- Department of Physics and Astronomy and London Centre for Nanotechnology, University College London, London WC1E 6BT, UK
| | - Andrea Zampetti
- Department of Physics and Astronomy and London Centre for Nanotechnology, University College London, London WC1E 6BT, UK
| | - Franco Cacialli
- Department of Physics and Astronomy and London Centre for Nanotechnology, University College London, London WC1E 6BT, UK
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Ding R, Wang XP, Feng J, Li XB, Dong FX, Tian WQ, Du JR, Fang HH, Wang HY, Yamao T, Hotta S, Sun HB. Clarification of the Molecular Doping Mechanism in Organic Single-Crystalline Semiconductors and their Application in Color-Tunable Light-Emitting Devices. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1801078. [PMID: 30260510 DOI: 10.1002/adma.201801078] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 07/27/2018] [Indexed: 06/08/2023]
Abstract
Organic single-crystalline semiconductors with long-range periodic order have attracted much attention for potential applications in electronic and optoelectronic devices due to their high carrier mobility, highly thermal stability, and low impurity content. Molecular doping has been proposed as a valuable strategy for improving the performance of organic semiconductors and semiconductor-based devices. However, a fundamental understanding of the inherent doping mechanism is still a key challenge impeding its practical application. In this study, solid evidence for the "perfect" substitutional doping mechanism of the stacking mode between the guest and host molecules in organic single-crystalline semiconductors using polarized photoluminescence spectrum measurements and first-principles calculations is provided. The molecular host-guest doping is further exploited for efficient color-tunable and even white organic single-crystal-based light-emitting devices by controlling the doping concentration. The clarification of the molecular doping mechanism in organic single-crystalline semiconductor host-guest system paves the way for their practical application in high-performance electronic and optoelectronic devices.
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Affiliation(s)
- Ran Ding
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun, 130012, China
- International Research Centre for Nano Handing and Manufacturing of China (CNM), Changchun University of Science and Technology, Changchun, 130022, China
| | - Xue-Peng Wang
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun, 130012, China
| | - Jing Feng
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun, 130012, China
| | - Xian-Bin Li
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun, 130012, China
| | - Feng-Xi Dong
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun, 130012, China
| | - Wei-Quan Tian
- College of Chemistry and Chemical Engineering, Chongqing University, Chongqing, 400044, China
| | - Jia-Ren Du
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun, 130012, China
| | - Hong-Hua Fang
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun, 130012, China
| | - Hai-Yu Wang
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun, 130012, China
| | - Takeshi Yamao
- Department of Macromolecular Science and Engineering, Graduate School of Science and Technology, Kyoto Institute of Technology, Matsugasaki Sakyo-ku, Kyoto, 606-8585, Japan
| | - Shu Hotta
- Department of Macromolecular Science and Engineering, Graduate School of Science and Technology, Kyoto Institute of Technology, Matsugasaki Sakyo-ku, Kyoto, 606-8585, Japan
| | - Hong-Bo Sun
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun, 130012, China
- State Key Lab of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Haidian, Beijing, 100084, China
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Han C, Zhang Z, Ding D, Xu H. Dipole-Dipole Interaction Management for Efficient Blue Thermally Activated Delayed Fluorescence Diodes. Chem 2018. [DOI: 10.1016/j.chempr.2018.06.005] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Kung TJ, Huang JY, Huang JJ, Tseng SH, Leung MK, Chiu TL, Lee JH, Wu YR. Modeling of carrier transport in organic light emitting diode with random dopant effects by two-dimensional simulation. OPTICS EXPRESS 2017; 25:25492-25503. [PMID: 29041216 DOI: 10.1364/oe.25.025492] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Accepted: 10/02/2017] [Indexed: 06/07/2023]
Abstract
To model the carrier transport in organic light-emitting diodes (OLEDs) with random dopant effects in the emitting layer, two-dimensional simulation was used. By including the Gaussian shape density of states and field-dependent mobility in the Poisson and drift-diffusion solver, the carrier transport, trapping in the dopant state, and radiative recombination were accurately modeled. To examine the model, the current-voltage characteristics of organic light-emitting devices were compared. The host material in the emitting layer was 2,2-bis(1-phenyl-1H-benzo[d]imidazol-2-yl)biphenyl (BImBP), which was doped with bis[2-(4,6-difluorophenyl)pyridinato-C2,N](picolinato)iridium(III) (FIrpic) at various concentrations. By including the random doping model, the trend of mobility was altered and the radiative efficiency fitted experimental values well.
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Kim M, Jeon SK, Lee JY. Molecular design approach of increasing the triplet energy of host materials using pyrrole as a core structure. RSC Adv 2015. [DOI: 10.1039/c5ra17469d] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Murawski C, Leo K, Gather MC. Efficiency roll-off in organic light-emitting diodes. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2013; 25:6801-27. [PMID: 24019178 DOI: 10.1002/adma.201301603] [Citation(s) in RCA: 346] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Revised: 06/23/2013] [Indexed: 05/25/2023]
Abstract
Organic light-emitting diodes (OLEDs) have attracted much attention in research and industry thanks to their capability to emit light with high efficiency and to deliver high-quality white light that provides good color rendering. OLEDs feature homogeneous large area emission and can be produced on flexible substrates. In terms of efficiency, OLEDs can compete with highly efficient conventional light sources but their efficiency typically decreases at high brightness levels, an effect known as efficiency roll-off. In recent years, much effort has been undertaken to understand the underlying processes and to develop methods that improve the high-brightness performance of OLEDs. In this review, we summarize the current knowledge and provide a detailed description of the relevant principles, both for phosphorescent and fluorescent emitter molecules. In particular, we focus on exciton-quenching mechanisms, such as triplet-triplet annihilation, quenching by polarons, or field-induced quenching, but also discuss mechanisms such as changes in charge carrier balance. We further review methods that may reduce the roll-off and thus enable OLEDs to be used in high-brightness applications.
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Affiliation(s)
- Caroline Murawski
- Institut für Angewandte Photophysik, Technische Universität Dresden, 01062, Dresden, Germany
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Key issues and recent progress of high efficient organic light-emitting diodes. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS 2013. [DOI: 10.1016/j.jphotochemrev.2013.08.001] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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9
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Fleetham T, Ecton J, Wang Z, Bakken N, Li J. Single-doped white organic light-emitting device with an external quantum efficiency over 20%. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2013; 25:2573-2576. [PMID: 23463599 DOI: 10.1002/adma.201204602] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 12/20/2012] [Indexed: 06/01/2023]
Abstract
A white OLED with a maximum EQE of 20.1%, CIE coordinates of (0.33, 0.33) and CRI of 80 is fabricated based on platinum(II) bis(N-methyl-imidazolyl)benzene chloride (Pt-16). The device emission spectrum and the chemical structure of Pt-16 are shown in the inset of the efficiency versus luminance graph.
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Affiliation(s)
- Tyler Fleetham
- Department of Material Science and Engineering, Arizona State University, Tempe, AZ 85284, USA
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Li G, Abiyasa AP, Gao J, Divayana Y, Chen W, Zhao Y, Sun XW, Zhang Q. Synthesis and Properties of a Diazopentacene Analogue. ASIAN J ORG CHEM 2012. [DOI: 10.1002/ajoc.201200120] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Lee S, Koo J, Hyung G, Lim D, Lee D, Lee K, Yoon S, Kim W, Kim Y. Effect of triplet multiple quantum well structures on the performance of blue phosphorescent organic light-emitting diodes. NANOSCALE RESEARCH LETTERS 2012; 7:23. [PMID: 22221777 PMCID: PMC3275519 DOI: 10.1186/1556-276x-7-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Accepted: 01/05/2012] [Indexed: 05/31/2023]
Abstract
We investigate multiple quantum well [MQW] structures with charge control layers [CCLs] to produce highly efficient blue phosphorescent organic light-emitting diodes [PHOLEDs]. Four types of devices from one to four quantum wells are fabricated following the number of CCLs which are mixed p- and n-type materials, maintaining the thickness of the emitting layer [EML]. Remarkably, such PHOLED with an optimized triplet MQW structure achieves maximum luminous and external quantum efficiency values of 19.95 cd/A and 10.05%, respectively. We attribute this improvement to the efficient triplet exciton confinement effect and the suppression of triplet-triplet annihilation which occurs within each EML. It also shows a reduction in the turn-on voltage from 3.5 V (reference device) to 2.5 V by the bipolar property of the CCLs.
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Affiliation(s)
- Seokjae Lee
- Department of Information Display, Hongik University, Seoul, 121-791, South Korea
| | - Jaryong Koo
- Department of Information Display, Hongik University, Seoul, 121-791, South Korea
| | - Gunwoo Hyung
- Department of Information Display, Hongik University, Seoul, 121-791, South Korea
| | - Donghwan Lim
- Department of Information Display, Hongik University, Seoul, 121-791, South Korea
| | - Donghyung Lee
- Department of Information Display, Hongik University, Seoul, 121-791, South Korea
| | - Kumhee Lee
- Department of Chemistry, Sungkyunkwan University, Suwon, 440-746, South Korea
| | - Seungsoo Yoon
- Department of Chemistry, Sungkyunkwan University, Suwon, 440-746, South Korea
| | - Wooyoung Kim
- School of Display Engineering, Hoseo University, Asan, 336-795, South Korea
| | - Youngkwan Kim
- Department of Information Display, Hongik University, Seoul, 121-791, South Korea
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Baumeier B, May F, Lennartz C, Andrienko D. Challenges for in silico design of organic semiconductors. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c2jm30182b] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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13
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Wu Y, Brédas JL. Simulations of the emission spectra of fac-tris(2-phenylpyridine) iridium and Duschinsky rotation effects using the Herman–Kluk semiclassical initial value representation method. J Chem Phys 2008; 129:214305. [DOI: 10.1063/1.3027514] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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