1
|
Adsetts JR, Whitworth Z, Chu K, Yang L, Zhang C, Ding Z. Closely Following Equivalent Circuit Changes during Operation of Graphene Dot Light‐Emitting Electrochemical Cells**. ChemElectroChem 2022. [DOI: 10.1002/celc.202101512] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
| | | | | | | | | | - Zhifeng Ding
- University of Western Ontario Chemistry 1151 Richmond St N6A5B7 London CANADA
| |
Collapse
|
2
|
Shanmugasundaram K, Been H, John JC, Puthanveedu A, Pharm NNT, Lee SG, Choe Y. Simple luminescent phenanthroimidazole emitters for solution-processed non-doped organic light-emitting electrochemical cells. NEW J CHEM 2021. [DOI: 10.1039/d1nj02811a] [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 luminescent materials with leveraging properties have attracted urgent demand for their commercial application in lighting devices.
Collapse
Affiliation(s)
- Kanagaraj Shanmugasundaram
- School of Chemical and Biomolecular Engineering, Pusan National University, Busan 46241, Republic of Korea
| | - HyeIn Been
- School of Chemical and Biomolecular Engineering, Pusan National University, Busan 46241, Republic of Korea
| | - Jino C. John
- School of Chemical and Biomolecular Engineering, Pusan National University, Busan 46241, Republic of Korea
| | - Archana Puthanveedu
- School of Chemical and Biomolecular Engineering, Pusan National University, Busan 46241, Republic of Korea
| | - Nguyet N. T. Pharm
- School of Chemical and Biomolecular Engineering, Pusan National University, Busan 46241, Republic of Korea
| | - Seung Geol Lee
- School of Chemical and Biomolecular Engineering, Pusan National University, Busan 46241, Republic of Korea
- Department of Organic Material Science and Engineering, Pusan National University, Busan 46241, Republic of Korea
| | - Youngson Choe
- School of Chemical and Biomolecular Engineering, Pusan National University, Busan 46241, Republic of Korea
| |
Collapse
|
3
|
John JC, Shanmugasundaram K, Brahmmananda Rao CVS, Gopakumar G, Choe Y. Furil-based ionic small molecules for green-emitting non-doped LECs with improved color purity. NEW J CHEM 2021. [DOI: 10.1039/d1nj00155h] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two novel furil-based small molecules FlBzPy and FlThPy were designed and synthesized with simple synthetic procedures for the first time for the LEC application.
Collapse
Affiliation(s)
- Jino C. John
- School of Chemical and Biomolecular Engineering
- Pusan National University
- Busan 609-735
- Republic of Korea
| | | | - C. V. S. Brahmmananda Rao
- Solution Chemistry & Mass Spectrometry Section
- Fuel Chemistry Division
- Indira Gandhi Centre for Atomic Research
- Kalpakkam 603102
- India
| | - Gopinadhanpillai Gopakumar
- Solution Chemistry & Mass Spectrometry Section
- Fuel Chemistry Division
- Indira Gandhi Centre for Atomic Research
- Kalpakkam 603102
- India
| | - Youngson Choe
- School of Chemical and Biomolecular Engineering
- Pusan National University
- Busan 609-735
- Republic of Korea
| |
Collapse
|
4
|
Shiu L, Chang B, Hsiao MC‐S, Sie W, Wu M, Huang L, Wang C, Lee G, Chang I, Su H, Shiu K. Alkyl‐Spacer Enhancement in Performance of Light‐Emitting Electrochemical Cells. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000528] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Ler‐Chun Shiu
- Department of Chemistry National Cheng Kung University 70101 Tainan Taiwan
| | - Bo‐Ren Chang
- Institute of Lighting and Energy Photonics National Chiao Tung University 71150 Tainan Taiwan
| | - Miles C. ‐S. Hsiao
- Department of Chemistry National Taiwan Normal University 11677 Taipei Taiwan
| | - Wu‐Sian Sie
- Department of Chemistry National Cheng Kung University 70101 Tainan Taiwan
| | - Ming‐Lun Wu
- Institute of Lighting and Energy Photonics National Chiao Tung University 71150 Tainan Taiwan
| | - Li‐Xian Huang
- Department of Chemistry National Cheng Kung University 70101 Tainan Taiwan
| | - Cheng‐Ming Wang
- Institute of Lighting and Energy Photonics National Chiao Tung University 71150 Tainan Taiwan
| | - Gene‐Hsiang Lee
- Instrument Center National Taiwan University 10617 Taipei Taiwan
| | - I‐Jy Chang
- Department of Chemistry National Taiwan Normal University 11677 Taipei Taiwan
| | - Hai‐Ching Su
- Institute of Lighting and Energy Photonics National Chiao Tung University 71150 Tainan Taiwan
| | - Kom‐Bei Shiu
- Department of Chemistry National Cheng Kung University 70101 Tainan Taiwan
| |
Collapse
|
5
|
Yi RH, Lo CL, Luo D, Lin CH, Weng SW, Lu CW, Liu SW, Chang CH, Su HC. Combinational Approach To Realize Highly Efficient Light-Emitting Electrochemical Cells. ACS APPLIED MATERIALS & INTERFACES 2020; 12:14254-14264. [PMID: 32155040 DOI: 10.1021/acsami.9b23300] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Light-emitting electrochemical cells (LECs) show high technical potential for display and lighting utilizations owing to the superior properties of solution processability, low operation voltage, and employing inert cathodes. For maximizing the device efficiency, three approaches including development of efficient emissive materials, optimizing the carrier balance, and maximizing the light extraction have been reported. However, most reported works focused on only one of the three optimization approaches. In this work, a combinational approach is demonstrated to optimize the device efficiency of LECs. A sophisticatedly designed yellow complex exhibiting a superior steric hindrance and a good carrier balance is proposed as the emissive material of light-emitting electrochemical cells and thus the external quantum efficiency (EQE) is up to 13.6%. With an improved carrier balance and reduced self-quenching by employing the host-guest strategy, the device EQE can be enhanced to 16.9%. Finally, a diffusive layer embedded between the glass substrate and the indium-tin-oxide layer is utilized to scatter the light trapped in the layered device structure, and consequently, a high EQE of 23.7% can be obtained. Such an EQE is impressive and consequently proves that the proposed combinational approach including adopting efficient emissive materials, optimizing the carrier balance, and maximizing the light extraction is effective in realizing highly efficient LECs.
Collapse
Affiliation(s)
- Rong-Huei Yi
- Department of Applied Chemistry, Providence University, Taichung 43301, Taiwan
| | - Chieh-Liang Lo
- Institute of Lighting and Energy Photonics, National Chiao Tung University, Tainan 71150, Taiwan
| | - Dian Luo
- Institute of Lighting and Energy Photonics, National Chiao Tung University, Tainan 71150, Taiwan
| | - Chien-Hsiang Lin
- Department of Applied Chemistry, Providence University, Taichung 43301, Taiwan
| | - Shu-Wen Weng
- Department of Photonics Engineering, Yuan Ze University, Chung-Li 32003, Taiwan
| | - Chin-Wei Lu
- Department of Applied Chemistry, Providence University, Taichung 43301, Taiwan
| | - Shun-Wei Liu
- Department of Electronic Engineering, Ming Chi University of Technology, New Taipei City 24301, Taiwan
| | - Chih-Hao Chang
- Department of Photonics Engineering, Yuan Ze University, Chung-Li 32003, Taiwan
| | - Hai-Ching Su
- Institute of Lighting and Energy Photonics, National Chiao Tung University, Tainan 71150, Taiwan
| |
Collapse
|
6
|
Frohleiks J, Wepfer S, Bacher G, Nannen E. Realization of Red Iridium-Based Ionic Transition Metal Complex Light-Emitting Electrochemical Cells (iTMC-LECs) by Interface-Induced Color Shift. ACS APPLIED MATERIALS & INTERFACES 2019; 11:22612-22620. [PMID: 31244025 DOI: 10.1021/acsami.9b07019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Red ionic iridium-based transition metal complex light-emitting electrochemical cells (iTMC-LECs) with emission centered at ca. 650 nm, maximum efficiency of 0.3%, maximum brightness above 650 cd m-2, and device lifetime well above 200 and 33 h at brightness levels of 10 and 210 cd m-2, respectively, are realized by the introduction of a p-type polymer interface to the standard design of [Ir(ppy)2(pbpy)]+[PF6]- (Hppy = 2-phenylpyridine, pbpy = 6-phenyl-2,2'-bipyridine) iTMC-LEC. The unexpected color shift from yellow to red is studied in detail with respect to operation conditions and material combination. The experimental data suggest that either exciplex formation or subordinate, usually suppressed optical transitions of the iTMC might become activated by the introduced interface, causing the pronounced red shift of the peak emission wavelength.
Collapse
Affiliation(s)
| | | | | | - Ekaterina Nannen
- Faculty of Electrical Engineering and Computer Science, Textile Innovatory , University of Applied Sciences Niederrhein , 47805 Krefeld , Germany
| |
Collapse
|
7
|
Frohleiks J, Gellner S, Wepfer S, Bacher G, Nannen E. Design and Realization of White Quantum Dot Light-Emitting Electrochemical Cell Hybrid Devices. ACS APPLIED MATERIALS & INTERFACES 2018; 10:42637-42646. [PMID: 30450895 DOI: 10.1021/acsami.8b15100] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The simple device architecture as well as the solution-based processing makes light-emitting electrochemical cells (LECs) a promising device concept for large-area flexible lighting solutions. The lack of deep-blue emitters, which are, at the same time, efficient, bright, and long-term stable, complementary to the wide variety of yellow-orange-emitting LECs, hampers the creation of white LECs. We present a hybrid device concept for the realization of white light emission by combining blue colloidal quantum dots (QDs) and an Ir-based ionic transition-metal complex (iTMC) LEC in a new type of white QD-LEC hybrid device (QLEC). By careful arrangement of the active layers, we yield light emission from both the blue QDs and the yellow iTMC emitter already at voltages below 3 V. The QLEC devices show homogeneous white light emission with high color rendering index (up to 80), luminance levels above 850 cd m-2, and a maximum external quantum efficiency greater than 0.2%.
Collapse
Affiliation(s)
- Julia Frohleiks
- Research Group "Solid State Lighting", NanoEnergieTechnikZentrum , University of Duisburg-Essen , Carl-Benz-Str. 199 , 47057 Duisburg , Germany
- Werkstoffe der Elektrotechnik and CENIDE , University of Duisburg-Essen , Bismarckstr. 81 , 47057 Duisburg , Germany
| | - Sandra Gellner
- Research Group "Solid State Lighting", NanoEnergieTechnikZentrum , University of Duisburg-Essen , Carl-Benz-Str. 199 , 47057 Duisburg , Germany
- Werkstoffe der Elektrotechnik and CENIDE , University of Duisburg-Essen , Bismarckstr. 81 , 47057 Duisburg , Germany
| | - Svenja Wepfer
- Research Group "Solid State Lighting", NanoEnergieTechnikZentrum , University of Duisburg-Essen , Carl-Benz-Str. 199 , 47057 Duisburg , Germany
- Werkstoffe der Elektrotechnik and CENIDE , University of Duisburg-Essen , Bismarckstr. 81 , 47057 Duisburg , Germany
| | - Gerd Bacher
- Werkstoffe der Elektrotechnik and CENIDE , University of Duisburg-Essen , Bismarckstr. 81 , 47057 Duisburg , Germany
| | - Ekaterina Nannen
- Research Group "Solid State Lighting", NanoEnergieTechnikZentrum , University of Duisburg-Essen , Carl-Benz-Str. 199 , 47057 Duisburg , Germany
- Werkstoffe der Elektrotechnik and CENIDE , University of Duisburg-Essen , Bismarckstr. 81 , 47057 Duisburg , Germany
| |
Collapse
|
8
|
He L, Wang X, Duan L. Enhancing the Overall Performances of Blue Light-Emitting Electrochemical Cells by Using an Electron-Injecting/Transporting Ionic Additive. ACS APPLIED MATERIALS & INTERFACES 2018; 10:11801-11809. [PMID: 29560719 DOI: 10.1021/acsami.8b00466] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Light-emitting electrochemical cells (LECs) have emerged as a promising emissive thin-film technology for next-generation solid-state lighting. However, blue LECs show low performances, which has remained a bottleneck for the fabrication of white LECs for lighting applications. Here, we demonstrate a remarkable enhancement of overall device performance for blue LECs by using an electron-injecting/transporting ionic additive, that is, [Zn(bpy)3](PF6)2 (bpy is 2.2'-bipyridine, PF6- is hexafluorophosphate). It is revealed that adding [Zn(bpy)3](PF6)2 into the active layers of blue LECs accelerates the device response, simultaneously enhances the brightness and efficiency, reduces the efficiency roll-offs, significantly improves the blue color stability upon the continuous electrical operation, and enhances the device operational stability at optimized conditions. The remarkable enhancement of the overall device performance upon adding [Zn(bpy)3](PF6)2 results from facilitated electron injection/transport and thus more balanced electron-hole recombination and more centered recombination zone, as well as the reduction of phosphorescence concentration quenching in the LECs. The work demonstrates for the first time that the use of electron-injecting/transporting ionic additives such as [Zn(bpy)3](PF6)2 is a facile yet effective strategy to remarkably boost the overall performances of blue LECs.
Collapse
Affiliation(s)
- Lei He
- College of Chemistry, Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Hubei International Scientific and Technological Cooperation Base of Pesticide and Green Synthesis , Central China Normal University , Wuhan , Hubei 430079 , P. R. China
| | - Xiaoxiang Wang
- College of Chemistry, Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Hubei International Scientific and Technological Cooperation Base of Pesticide and Green Synthesis , Central China Normal University , Wuhan , Hubei 430079 , P. R. China
| | - Lian Duan
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry , Tsinghua University , Beijing 100084 , P. R. China
| |
Collapse
|
9
|
Design rules for light-emitting electrochemical cells delivering bright luminance at 27.5 percent external quantum efficiency. Nat Commun 2017; 8:1190. [PMID: 29085078 PMCID: PMC5662711 DOI: 10.1038/s41467-017-01339-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Accepted: 09/12/2017] [Indexed: 11/08/2022] Open
Abstract
The light-emitting electrochemical cell promises cost-efficient, large-area emissive applications, as its characteristic in-situ doping enables use of air-stabile electrodes and a solution-processed single-layer active material. However, mutual exclusion of high efficiency and high brightness has proven a seemingly fundamental problem. Here we present a generic approach that overcomes this critical issue, and report on devices equipped with air-stabile electrodes and outcoupling structure that deliver a record-high efficiency of 99.2 cd A-1 at a bright luminance of 1910 cd m-2. This device significantly outperforms the corresponding optimized organic light-emitting diode despite the latter employing calcium as the cathode. The key to this achievement is the design of the host-guest active material, in which tailored traps suppress exciton diffusion and quenching in the central recombination zone, allowing efficient triplet emission. Simultaneously, the traps do not significantly hamper electron and hole transport, as essentially all traps in the transport regions are filled by doping.
Collapse
|
10
|
Pal AK, Cordes DB, Slawin AMZ, Momblona C, Ortí E, Samuel IDW, Bolink HJ, Zysman-Colman E. Synthesis, Properties, and Light-Emitting Electrochemical Cell (LEEC) Device Fabrication of Cationic Ir(III) Complexes Bearing Electron-Withdrawing Groups on the Cyclometallating Ligands. Inorg Chem 2016; 55:10361-10376. [PMID: 27681985 PMCID: PMC5080635 DOI: 10.1021/acs.inorgchem.6b01602] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Indexed: 11/28/2022]
Abstract
The structure-property relationship study of a series of cationic Ir(III) complexes in the form of [Ir(C^N)2(dtBubpy)]PF6 [where dtBubpy = 4,4'-di-tert-butyl-2,2'-bipyridine and C^N = cyclometallating ligand bearing an electron-withdrawing group (EWG) at C4 of the phenyl substituent, i.e., -CF3 (1), -OCF3 (2), -SCF3 (3), -SO2CF3 (4)] has been investigated. The physical and optoelectronic properties of the four complexes were comprehensively characterized, including by X-ray diffraction analysis. All the complexes exhibit quasireversible dtBubpy-based reductions from -1.29 to -1.34 V (vs SCE). The oxidation processes are likewise quasireversible (metal + C^N ligand) and are between 1.54 and 1.72 V (vs SCE). The relative oxidation potentials follow a general trend associated with the Hammett parameter (σ) of the EWGs. Surprisingly, complex 4 bearing the strongest EWG does not adhere to the expected Hammett behavior and was found to exhibit red-shifted absorption and emission maxima. Nevertheless, the concept of introducing EWGs was found to be generally useful in blue-shifting the emission maxima of the complexes (λem = 484-545 nm) compared to that of the prototype complex [Ir(ppy)2(dtBubpy)]PF6 (where ppy = 2-phenylpyridinato) (λem = 591 nm). The complexes were found to be bright emitters in solution at room temperature (ΦPL = 45-66%) with microsecond excited-state lifetimes (τe = 1.14-4.28 μs). The photophysical properties along with density functional theory (DFT) calculations suggest that the emission of these complexes originates from mixed contributions from ligand-centered (LC) transitions and mixed metal-to-ligand and ligand-to-ligand charge transfer (LLCT/MLCT) transitions, depending on the EWG. In complexes 1, 3, and 4 the 3LC character is prominent over the mixed 3CT character, while in complex 2, the mixed 3CT character is much more pronounced, as demonstrated by DFT calculations and the observed positive solvatochromism effect. Due to the quasireversible nature of the oxidation and reduction waves, fabrication of light-emitting electrochemical cells (LEECs) using these complexes as emitters was possible with the LEECs showing moderate efficiencies.
Collapse
Affiliation(s)
- Amlan K. Pal
- Organic Semiconductor Centre, EaStCHEM
School of Chemistry, University of St Andrews, St Andrews, Fife KY16 9ST, United Kingdom
| | - David B. Cordes
- EaStCHEM School of Chemistry, University
of St Andrews, St Andrews, Fife KY16 9ST, United Kingdom
| | - Alexandra M. Z. Slawin
- EaStCHEM School of Chemistry, University
of St Andrews, St Andrews, Fife KY16 9ST, United Kingdom
| | - Cristina Momblona
- Instituto de Ciencia Molecular, Universidad de Valencia, C/J. Beltran 2, 46980 Paterna, Spain
| | - Enrique Ortí
- Instituto de Ciencia Molecular, Universidad de Valencia, C/J. Beltran 2, 46980 Paterna, Spain
| | - Ifor D. W. Samuel
- Organic Semiconductor
Centre, SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, United Kingdom
| | - Henk J. Bolink
- Instituto de Ciencia Molecular, Universidad de Valencia, C/J. Beltran 2, 46980 Paterna, Spain
| | - Eli Zysman-Colman
- Organic Semiconductor Centre, EaStCHEM
School of Chemistry, University of St Andrews, St Andrews, Fife KY16 9ST, United Kingdom
| |
Collapse
|
11
|
Frohleiks J, Wepfer S, Kelestemur Y, Demir HV, Bacher G, Nannen E. Quantum Dot/Light-Emitting Electrochemical Cell Hybrid Device and Mechanism of Its Operation. ACS APPLIED MATERIALS & INTERFACES 2016; 8:24692-24698. [PMID: 27557045 DOI: 10.1021/acsami.6b06833] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
A new type of light-emitting hybrid device based on colloidal quantum dots (QDs) and an ionic transition metal complex (iTMC) light-emitting electrochemical cell (LEC) is introduced. The developed hybrid devices show light emission from both active layers, which are combined in a stacked geometry. Time-resolved photoluminescence experiments indicate that the emission is controlled by direct charge injection into both the iTMC and the QD layer. The turn-on time (time to reach 1 cd/m(2)) at constant voltage operation is significantly reduced from 8 min in the case of the reference LEC down to subsecond in the case of the hybrid device. Furthermore, luminance and efficiency of the hybrid device are enhanced compared to reference LEC directly after device turn-on by a factor of 400 and 650, respectively. We attribute these improvements to an increased electron injection efficiency into the iTMC directly after device turn-on.
Collapse
Affiliation(s)
- Julia Frohleiks
- Research Group "Solid State Lighting", NanoEnergieTechnikZentrum, University Duisburg-Essen , 47057 Duisburg, Germany
- Werkstoffe der Elektrotechnik and CENIDE, University Duisburg-Essen , 47057 Duisburg, Germany
| | - Svenja Wepfer
- Research Group "Solid State Lighting", NanoEnergieTechnikZentrum, University Duisburg-Essen , 47057 Duisburg, Germany
- Werkstoffe der Elektrotechnik and CENIDE, University Duisburg-Essen , 47057 Duisburg, Germany
| | - Yusuf Kelestemur
- Department of Electrical and Electronics Engineering, Department of Physics, UNAM-Institute of Materials Science and Nanotechnology, Bilkent University , Ankara 06800, Turkey
| | - Hilmi Volkan Demir
- Department of Electrical and Electronics Engineering, Department of Physics, UNAM-Institute of Materials Science and Nanotechnology, Bilkent University , Ankara 06800, Turkey
- Luminous! Center of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, School of Physical and Materials Sciences, School of Materials Science and Nanotechnology, Nanyang Technological University , Singapore 639798, Singapore
| | - Gerd Bacher
- Werkstoffe der Elektrotechnik and CENIDE, University Duisburg-Essen , 47057 Duisburg, Germany
| | - Ekaterina Nannen
- Research Group "Solid State Lighting", NanoEnergieTechnikZentrum, University Duisburg-Essen , 47057 Duisburg, Germany
- Werkstoffe der Elektrotechnik and CENIDE, University Duisburg-Essen , 47057 Duisburg, Germany
| |
Collapse
|
12
|
Henwood AF, Zysman-Colman E. Luminescent Iridium Complexes Used in Light-Emitting Electrochemical Cells (LEECs). Top Curr Chem (Cham) 2016; 374:36. [PMID: 27573388 PMCID: PMC5480411 DOI: 10.1007/s41061-016-0036-0] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Accepted: 05/09/2016] [Indexed: 11/04/2022]
Abstract
Cationic iridium(III) complexes represent the single largest class of emitters used in light emitting electrochemical cells (LEECs). In this chapter, we highlight the state-of-the-art emitters in terms of efficiency and stability in LEEC devices, highlighting blue, green, yellow/orange, red and white devices, and provide an outlook to the future of LEECs.
Collapse
Affiliation(s)
- Adam F Henwood
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife, KY16 9ST, UK
| | - Eli Zysman-Colman
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife, KY16 9ST, UK.
| |
Collapse
|
13
|
Huang PC, Krucaite G, Su HC, Grigalevicius S. Incorporating a hole-transport material into the emissive layer of solid-state light-emitting electrochemical cells to improve device performance. Phys Chem Chem Phys 2015; 17:17253-9. [PMID: 26074493 DOI: 10.1039/c5cp02034d] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Solid-state light-emitting electrochemical cells (LECs) based on ionic transition metal complexes (iTMCs) have several advantages such as high efficiency, low operation voltage and simple device structure. To improve the device efficiency of iTMC-based LECs for practical applications, improving the carrier balance to achieve a centered recombination zone would be an important issue. In this work, incorporating a hole-transport material (HTM) into the emissive layer of iTMC-based LECs is shown to improve device performance. When mixed with an HTM (12%), the LECs based on a Ru complex exhibit 1.9× and 1.5× enhancement in peak light output and peak external quantum efficiency (EQE) as compared to neat-film devices. Furthermore, over 2× enhancement in stabilized EQE can be achieved in LECs mixed with an HTM. It is attributed to that a more centered recombination zone in LECs mixed with an HTM is beneficial in reducing exciton quenching in the recombination zone approaching extended doped layers. Estimating the temporal evolution of the recombination zone in the LECs mixed with an HTM by employing the microcavity effect is demonstrated to confirm the physical origin for improved device performance. These results reveal that incorporating of an HTM in the emissive layer of LECs based on an iTMC is a feasible way to improve carrier balance and thus enhance light output and device efficiency.
Collapse
Affiliation(s)
- Po-Chin Huang
- Institute of Lighting and Energy Photonics, National Chiao Tung University, Tainan 71150, Taiwan.
| | | | | | | |
Collapse
|
14
|
Lin GR, Chen HF, Shih HC, Hsu JH, Chang Y, Chiu CH, Cheng CY, Yeh YS, Su HC, Wong KT. Non-doped solid-state white light-emitting electrochemical cells employing the microcavity effect. Phys Chem Chem Phys 2015; 17:6956-62. [DOI: 10.1039/c4cp05380j] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
White electroluminescence can be obtained in non-doped light-emitting electrochemical cells (LECs) by employing the microcavity effect.
Collapse
Affiliation(s)
- Guan-Rung Lin
- Institute of Lighting and Energy Photonics
- National Chiao Tung University
- Tainan 71150
- Taiwan
| | - Hsiao-Fan Chen
- Department of Chemistry
- National Taiwan University
- Taipei 10617
- Taiwan
| | - Hsien-Chang Shih
- Institute of Lighting and Energy Photonics
- National Chiao Tung University
- Tainan 71150
- Taiwan
| | - Jia-Hong Hsu
- Institute of Lighting and Energy Photonics
- National Chiao Tung University
- Tainan 71150
- Taiwan
| | - Yi Chang
- Institute of Lighting and Energy Photonics
- National Chiao Tung University
- Tainan 71150
- Taiwan
| | - Chih-Hung Chiu
- Institute of Lighting and Energy Photonics
- National Chiao Tung University
- Tainan 71150
- Taiwan
| | - Chia-Yu Cheng
- Institute of Lighting and Energy Photonics
- National Chiao Tung University
- Tainan 71150
- Taiwan
| | - Yun-Shiuan Yeh
- Department of Chemistry
- National Taiwan University
- Taipei 10617
- Taiwan
| | - Hai-Ching Su
- Institute of Lighting and Energy Photonics
- National Chiao Tung University
- Tainan 71150
- Taiwan
| | - Ken-Tsung Wong
- Department of Chemistry
- National Taiwan University
- Taipei 10617
- Taiwan
| |
Collapse
|
15
|
Su HC, Hsu JH. Improving the carrier balance of light-emitting electrochemical cells based on ionic transition metal complexes. Dalton Trans 2015; 44:8330-45. [DOI: 10.1039/c4dt01675k] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Improved carrier balance of a light-emitting electrochemical cell reduces exciton quenching near the doped layers, rendering a higher device efficiency.
Collapse
Affiliation(s)
- Hai-Ching Su
- Institute of Lighting and Energy Photonics
- National Chiao Tung University
- Tainan 71150
- Taiwan
| | - Jia-Hong Hsu
- Institute of Lighting and Energy Photonics
- National Chiao Tung University
- Tainan 71150
- Taiwan
| |
Collapse
|
16
|
Su HC, Cheng CY. Recent Advances in Solid-State White Light-Emitting Electrochemical Cells. Isr J Chem 2014. [DOI: 10.1002/ijch.201400043] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
17
|
Dumke JC, Qureshi A, Hamdan S, El-Zahab B, Das S, Hayes DJ, Boldor D, Rupnik K, Warner IM. Photothermal response of near-infrared-absorbing NanoGUMBOS. APPLIED SPECTROSCOPY 2014; 68:340-352. [PMID: 24666951 DOI: 10.1366/13-07268] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The photothermal properties of several near-infrared-absorbing nanoparticles derived from group of uniform materials based on organic salts (GUMBOS) and composed of cationic dyes coupled with biocompatible anions are evaluated. These nanoparticles were synthesized using a reprecipitation method performed at various pH values: 2.0, 5.0, 7.0, 9.0, and 11.0. The cations for the nanoparticles derived from GUMBOS (nanoGUMBOS), [1048] and [1061], have absorbance maxima at wavelengths overlapping with human soft tissue absorbance minima. Near-infrared-absorbing nanoGUMBOS excited with a 1064 nm continuous laser led to heat generation, with an average temperature increase of 20.4 ± 2.7 °C. Although the [1061][Deoxycholate] nanoGUMBOS generated the highest temperature increase (23.7 ± 2.4 °C), it was the least photothermally efficient compound (13.0%) due to its relatively large energy band gap of 0.892 eV. The more photothermally efficient compound [1048][Ascorbate] (64.4%) had a smaller energy band gap of 0.861 eV and provided an average photothermal temperature increase of 21.0 ± 2.1 °C.
Collapse
Affiliation(s)
- Jonathan C Dumke
- Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803 USA
| | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Lumineszierende ionische Übergangsmetallkomplexe für leuchtende elektrochemische Zellen. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201201471] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
19
|
Costa RD, Ortí E, Bolink HJ, Monti F, Accorsi G, Armaroli N. Luminescent Ionic Transition-Metal Complexes for Light-Emitting Electrochemical Cells. Angew Chem Int Ed Engl 2012; 51:8178-211. [DOI: 10.1002/anie.201201471] [Citation(s) in RCA: 791] [Impact Index Per Article: 65.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
|
20
|
Liao CT, Chen HF, Su HC, Wong KT. Tailoring carrier injection efficiency to improve the carrier balance of solid-state light-emitting electrochemical cells. Phys Chem Chem Phys 2012; 14:9774-84. [DOI: 10.1039/c2cp40739f] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
21
|
Su HC, Chen HF, Chen PH, Lin SW, Liao CT, Wong KT. Efficient solid-state white light-emitting electrochemical cells based on phosphorescent sensitization. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c2jm35483g] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
22
|
Liao CT, Chen HF, Su HC, Wong KT. Improving the balance of carrier mobilities of host-guest solid-state light-emitting electrochemical cells. Phys Chem Chem Phys 2011; 14:1262-9. [PMID: 22134581 DOI: 10.1039/c1cp23336j] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report efficient host-guest solid-state light-emitting electrochemical cells (LECs) utilizing a cationic terfluorene derivative as the host and a red-emitting cationic transition metal complex as the guest. Carrier trapping induced by the energy offset in the lowest unoccupied molecular orbital (LUMO) levels between the host and the guest impedes electron transport in the host-guest films and thus improves the balance of carrier mobilities of the host films intrinsically exhibiting electron preferred transporting characteristics. Photoluminescence measurements show efficient energy transfer in this host-guest system and thus ensure predominant guest emission at low guest concentrations, rendering significantly reduced self-quenching of guest molecules. EL measurements show that the peak EQE (power efficiency) of the host-guest LECs reaches 3.62% (7.36 lm W(-1)), which approaches the upper limit that one would expect from the photoluminescence quantum yield of the emissive layer (∼0.2) and an optical out-coupling efficiency of ∼20% and consequently indicates superior balance of carrier mobilities in such a host-guest emissive layer. These results are among the highest reported for red-emitting LECs and thus confirm that in addition to reducing self-quenching of guest molecules, the strategy of utilizing a carrier transporting host doped with a proper carrier trapping guest would improve balance of carrier mobilities in the host-guest emissive layer, offering an effective approach for optimizing device efficiencies of LECs.
Collapse
Affiliation(s)
- Chih-Teng Liao
- Institute of Lighting and Energy Photonics, National Chiao Tung University, Tainan 71150, Taiwan
| | | | | | | |
Collapse
|