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Xing X, Wu Z, Sun Y, Liu Y, Dong X, Li S, Wang W. The Optimization of Hole Injection Layer in Organic Light-Emitting Diodes. NANOMATERIALS (BASEL, SWITZERLAND) 2024; 14:161. [PMID: 38251126 PMCID: PMC10819190 DOI: 10.3390/nano14020161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 01/02/2024] [Accepted: 01/10/2024] [Indexed: 01/23/2024]
Abstract
Organic light-emitting diodes (OLEDs) are widely recognized as the forefront technology for displays and lighting technology. Now, the global OLED market is nearly mature, driven by the rising demand for superior displays in smartphones. In recent years, numerous strategies have been introduced and demonstrated to optimize the hole injection layer to further enhance the efficiency of OLEDs. In this paper, different methods of optimizing the hole injection layer were elucidated, including using a suitable hole injection material to minimize the hole injection barrier and match the energy level with the emission layer, exploring new preparation methods to optimize the structure of hole injection layer, and so on. Meanwhile, this article can help people to understand the current research progress and the challenges still faced in relation to the hole injection layer in OLEDs, providing future research directions to enhance the properties of OLEDs.
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Affiliation(s)
- Xiaolin Xing
- School of Physical Science and Information Technology, Liaocheng University, Liaocheng 252059, China; (X.X.); (Z.W.); (Y.S.); (X.D.); (S.L.)
- Shandong Provincial Key Laboratory of Optical Communication Science and Technology, Liaocheng 252059, China
| | - Ziye Wu
- School of Physical Science and Information Technology, Liaocheng University, Liaocheng 252059, China; (X.X.); (Z.W.); (Y.S.); (X.D.); (S.L.)
- Shandong Provincial Key Laboratory of Optical Communication Science and Technology, Liaocheng 252059, China
| | - Yingying Sun
- School of Physical Science and Information Technology, Liaocheng University, Liaocheng 252059, China; (X.X.); (Z.W.); (Y.S.); (X.D.); (S.L.)
- Shandong Provincial Key Laboratory of Optical Communication Science and Technology, Liaocheng 252059, China
| | - Yunlong Liu
- School of Physical Science and Information Technology, Liaocheng University, Liaocheng 252059, China; (X.X.); (Z.W.); (Y.S.); (X.D.); (S.L.)
- Shandong Provincial Key Laboratory of Optical Communication Science and Technology, Liaocheng 252059, China
| | - Xiaochen Dong
- School of Physical Science and Information Technology, Liaocheng University, Liaocheng 252059, China; (X.X.); (Z.W.); (Y.S.); (X.D.); (S.L.)
- Shandong Provincial Key Laboratory of Optical Communication Science and Technology, Liaocheng 252059, China
- Key Laboratory of Flexible Electronics (KLOFE), Institute of Advanced Materials (IAM), School of Physical and Mathematical Sciences, Nanjing Tech University (NanjingTech), Nanjing 211800, China
| | - Shuhong Li
- School of Physical Science and Information Technology, Liaocheng University, Liaocheng 252059, China; (X.X.); (Z.W.); (Y.S.); (X.D.); (S.L.)
- Shandong Provincial Key Laboratory of Optical Communication Science and Technology, Liaocheng 252059, China
| | - Wenjun Wang
- School of Physical Science and Information Technology, Liaocheng University, Liaocheng 252059, China; (X.X.); (Z.W.); (Y.S.); (X.D.); (S.L.)
- Shandong Provincial Key Laboratory of Optical Communication Science and Technology, Liaocheng 252059, China
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Woo JY, Park MH, Jeong SH, Kim YH, Kim B, Lee TW, Han TH. Advances in Solution-Processed OLEDs and their Prospects for Use in Displays. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2207454. [PMID: 36300804 DOI: 10.1002/adma.202207454] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 10/05/2022] [Indexed: 06/16/2023]
Abstract
This review outlines problems and progress in development of solution-processed organic light-emitting diodes (SOLEDs) in industry and academia. Solution processing has several advantages such as low consumption of materials, low-cost processing, and large-area manufacturing. However, use of a solution process entails complications, such as the need for solvent resistivity and solution-processable materials, and yields SOLEDs that have limited luminous efficiency, severe roll-off characteristics, and short lifetime compared to OLEDs fabricated using thermal evaporation. These demerits impede production of practical SOLED displays. This review outlines the industrial demands for commercial SOLEDs and the current status of SOLED development in industries and academia, and presents research guidelines for the development of SOLEDs that have high efficiency, long lifetime, and good processability to achieve commercialization.
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Affiliation(s)
- Joo Yoon Woo
- Division of Materials Science and Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul, 04763, Republic of Korea
| | - Min-Ho Park
- Department of Organic Materials and Fiber Engineering, Soongsil University, 369 Sangdo-Ro, Dongjak-Gu, Seoul, 06978, Republic of Korea
| | - Su-Hun Jeong
- Future Technology Research Center, LG Chem, Ltd., 30, Magokjunang 10-ro, Gangseo-gu, Seoul, 07794, Republic of Korea
| | - Young-Hoon Kim
- Department of Energy Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul, 04763, Republic of Korea
| | - Byungjae Kim
- Future Technology Research Center, LG Chem, Ltd., 30, Magokjunang 10-ro, Gangseo-gu, Seoul, 07794, Republic of Korea
| | - Tae-Woo Lee
- Department of Materials Science and Engineering, School of Chemical and Biological Engineering, Institute of Engineering Research, Research Institute of Advanced Materials, Soft Foundry, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Tae-Hee Han
- Division of Materials Science and Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul, 04763, Republic of Korea
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3
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Hwang JH, Seo E, Park S, Lee K, Kim DH, Lee SH, Kwon YW, Roh J, Lim J, Lee D. All-Solution-Processed Quantum Dot Light-Emitting Diode Using Phosphomolybdic Acid as Hole Injection Layer. MATERIALS (BASEL, SWITZERLAND) 2023; 16:1371. [PMID: 36837001 PMCID: PMC9960878 DOI: 10.3390/ma16041371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/21/2023] [Accepted: 01/31/2023] [Indexed: 06/18/2023]
Abstract
In this study, we investigate phosphomolybdic acid (PMA), which allows solution processing of quantum dot light-emitting diodes. With its low cost, easy solution processes, and excellent physical and optical properties, PMA is a potential candidate as the hole injection layer (HIL) in optoelectronic devices. We evaluate the physical and electrical properties of PMA using various solvents. The surface morphology of the PMA film was improved using a solvent with appropriate boiling points, surface tension, and viscosity to form a smooth, pinhole-free film. The energy level was regulated according to the solvent, and PMA with the appropriate electronic structure provided balanced charge carrier transport in quantum dot electroluminescent (QD-EL) devices with enhanced efficiency. A device using PMA dissolved in cyclohexanone was demonstrated to exhibit improved efficiency compared to a device using PEDOT:PSS, which is a conventional solution HIL. However, the stability of PMA was slightly poorer than PEDOT:PSS; there needs to be further investigation.
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Affiliation(s)
- Jeong Ha Hwang
- Department of Semiconductor Engineering, Gyeongsang National University, Jinju 52828, Republic of Korea
| | - Eunyong Seo
- Department of Semiconductor Engineering, Gyeongsang National University, Jinju 52828, Republic of Korea
| | - Sangwook Park
- Department of Electrical Engineering, Pusan National University, Busan 46241, Republic of Korea
| | - Kyungjae Lee
- Department of Semiconductor Engineering, Gyeongsang National University, Jinju 52828, Republic of Korea
| | - Dong Hyun Kim
- Department of Semiconductor Engineering, Gyeongsang National University, Jinju 52828, Republic of Korea
| | - Seok Hyoung Lee
- Department of Semiconductor Engineering, Gyeongsang National University, Jinju 52828, Republic of Korea
| | - Yong Woo Kwon
- Department of Energy Science, Center for Artificial Atoms, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Jeongkyun Roh
- Department of Electrical Engineering, Pusan National University, Busan 46241, Republic of Korea
| | - Jaehoon Lim
- Department of Energy Science, Center for Artificial Atoms, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Donggu Lee
- Department of Semiconductor Engineering, Gyeongsang National University, Jinju 52828, Republic of Korea
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Wu Q, Gong X, Zhao D, Zhao YB, Cao F, Wang H, Wang S, Zhang J, Quintero-Bermudez R, Sargent EH, Yang X. Efficient Tandem Quantum-Dot LEDs Enabled by An Inorganic Semiconductor-Metal-Dielectric Interconnecting Layer Stack. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2108150. [PMID: 34761462 DOI: 10.1002/adma.202108150] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Indexed: 06/13/2023]
Abstract
Light-emitting diodes (LEDs) in a tandem configuration offer a strategy to realize high-performance, multicolor devices. Until now, though, the efficiency of tandem colloidal quantum dot LEDs (QLEDs) has been limited due to unpassivated interfaces and solvent damage originating from the materials processing requirements of interconnecting layers (ICLs). Here an ICL is reported consisting of a semiconductor-metal-dielectric stack that provides facile fabrication, materials stability, and good optoelectronic coupling. It is investigated experimentally how the ICL enables charge balance, suppresses current leakage, and prevents solvent damage to the underlying layers. As a result record efficiencies are reported for double-junction tandem QLEDs, whose emission wavelengths cover from blue to red light; i.e., external quantum efficiencies (EQEs) of 40% (average 37+/-2%) for red, 49% (average 45+/-2%) for yellow, 50% (average 46+/-2%) for green, and 24% (average 21+/-2%) for blue are achieved.
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Affiliation(s)
- Qianqian Wu
- Key Laboratory of Advanced Display and System Applications of Ministry of Education, Shanghai University, 149 Yanchang Road, Shanghai, 200072, China
| | - Xiwen Gong
- Department of Electrical and Computer Engineering, University of Toronto, 35 St. George Street, Toronto, Ontario, M5S 1A4, Canada
| | - Dewei Zhao
- Institute of Solar Energy Materials and Devices, College of Materials Science and Engineering, Sichuan University, No. 24 South Section 1, Yihuan Road, Chengdu, 610065, China
| | - Yong-Biao Zhao
- Department of Electrical and Computer Engineering, University of Toronto, 35 St. George Street, Toronto, Ontario, M5S 1A4, Canada
| | - Fan Cao
- Key Laboratory of Advanced Display and System Applications of Ministry of Education, Shanghai University, 149 Yanchang Road, Shanghai, 200072, China
| | - Haoran Wang
- Key Laboratory of Advanced Display and System Applications of Ministry of Education, Shanghai University, 149 Yanchang Road, Shanghai, 200072, China
| | - Sheng Wang
- Key Laboratory of Advanced Display and System Applications of Ministry of Education, Shanghai University, 149 Yanchang Road, Shanghai, 200072, China
| | - Jianhua Zhang
- Key Laboratory of Advanced Display and System Applications of Ministry of Education, Shanghai University, 149 Yanchang Road, Shanghai, 200072, China
| | - Rafael Quintero-Bermudez
- Department of Electrical and Computer Engineering, University of Toronto, 35 St. George Street, Toronto, Ontario, M5S 1A4, Canada
| | - Edward H Sargent
- Department of Electrical and Computer Engineering, University of Toronto, 35 St. George Street, Toronto, Ontario, M5S 1A4, Canada
| | - Xuyong Yang
- Key Laboratory of Advanced Display and System Applications of Ministry of Education, Shanghai University, 149 Yanchang Road, Shanghai, 200072, China
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Cao F, Wu Q, Sui Y, Wang S, Dou Y, Hua W, Kong L, Wang L, Zhang J, Jiang T, Yang X. All-Inorganic Quantum Dot Light-Emitting Diodes with Suppressed Luminance Quenching Enabled by Chloride Passivated Tungsten Phosphate Hole Transport Layers. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2100030. [PMID: 33783126 DOI: 10.1002/smll.202100030] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/08/2021] [Indexed: 06/12/2023]
Abstract
Although excellent performance such as high efficiency and stability have been achieved in quantum dot (QD)-based light-emitting diodes (QLEDs) possessing an organic/inorganic hybrid device structure, the highly expected all-inorganic QLEDs remain at the bottleneck stage in recent years, resulting from the luminance quenching of QDs caused by inorganic hole transport layer (HTL) and unbalanced charge injection due to large energy barrier for injecting holes from HTL to QDs. Here, it is reported that the solution-processed inorganic environmentally friendly chloride (Cl)-passivated tungsten phosphate (Cl@TPA) films serve as HTL. The incorporation of Cl in TPA effectively passivates the oxygen vacancies, which not only avoids the luminescence quenching of QDs by reducing carrier concentration but also facilitates the hole injection from HTL to QDs with a favorable electronic band alignment, thus achieving the record external quantum efficiency of ≈9.27%, among all previous reports about all-inorganic QLEDs. Most importantly, the resulting all-inorganic QLEDs with Cl@TPA exhibit a substantial improvement in the operational lifetime (T50 > 105 h under an initial luminance of 100 cd m-2 ), which is almost 30-fold higher than the devices with TPA HTL. This work furnishes a promising strategy for highly efficient and stable QLEDs based on inorganic device structure.
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Affiliation(s)
- Fan Cao
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha, 410073, China
| | - Qianqian Wu
- Key Laboratory of Advanced Display and System Applications of Ministry of Education, Shanghai University, 149 Yanchang Road, Shanghai, 200072, China
| | - Yizhen Sui
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha, 410073, China
| | - Sheng Wang
- Key Laboratory of Advanced Display and System Applications of Ministry of Education, Shanghai University, 149 Yanchang Road, Shanghai, 200072, China
| | - Yongjiang Dou
- Key Laboratory of Advanced Display and System Applications of Ministry of Education, Shanghai University, 149 Yanchang Road, Shanghai, 200072, China
| | - Weihong Hua
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha, 410073, China
| | - Lingmei Kong
- Key Laboratory of Advanced Display and System Applications of Ministry of Education, Shanghai University, 149 Yanchang Road, Shanghai, 200072, China
| | - Lin Wang
- Key Laboratory of Advanced Display and System Applications of Ministry of Education, Shanghai University, 149 Yanchang Road, Shanghai, 200072, China
| | - Jianhua Zhang
- Key Laboratory of Advanced Display and System Applications of Ministry of Education, Shanghai University, 149 Yanchang Road, Shanghai, 200072, China
| | - Tian Jiang
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha, 410073, China
| | - Xuyong Yang
- Key Laboratory of Advanced Display and System Applications of Ministry of Education, Shanghai University, 149 Yanchang Road, Shanghai, 200072, China
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6
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Liu L, Dong R, Ye D, Lu Y, Xia P, Deng L, Duan Y, Cao K, Chen S. Phosphomolybdic Acid-Modified Monolayer Graphene Anode for Efficient Organic and Perovskite Light-Emitting Diodes. ACS APPLIED MATERIALS & INTERFACES 2021; 13:12268-12277. [PMID: 33656843 DOI: 10.1021/acsami.0c22456] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Graphene is a promising flexible transparent electrode, and significant progress in graphene-based optoelectronic devices has been accomplished by reducing the sheet resistance and tuning the work function. Herein, phosphomolybdic acid (PMA) is proposed as a novel p-type chemical dopant for graphene, and the optical and electrical properties of graphene are investigated systematically. As a result, the monolayer graphene electrode with lower sheet resistance and work function are obtained while maintaining a high transmittance. The Raman spectrum proves the p-type doping effect of PMA on graphene, and the X-ray photoelectron spectroscopy results reveal the mechanism, which is that the electrons transfer from graphene to PMA through the Mo-O-C bond. Furthermore, using the PMA-doped graphene anode, organic and perovskite light-emitting diodes obtained the maximum efficiencies of 129.3 and 15.6 cd/A with an increase of 50.8 and 36.8% compared with the pristine counterparts, respectively. This work confirms that PMA is a potential p-type chemical dopant to achieve an ideal graphene electrode and demonstrates the feasibility of PMA-doped graphene in the practical application of next-generation displays and solid-state lighting.
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Affiliation(s)
- Lihui Liu
- Key Laboratory for Organic Electronics and Information Displays (KLOEID), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications (NUPT), Nanjing 210023, China
| | - Ruimin Dong
- Key Laboratory for Organic Electronics and Information Displays (KLOEID), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications (NUPT), Nanjing 210023, China
| | - Danqing Ye
- Key Laboratory for Organic Electronics and Information Displays (KLOEID), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications (NUPT), Nanjing 210023, China
| | - Yao Lu
- Key Laboratory for Organic Electronics and Information Displays (KLOEID), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications (NUPT), Nanjing 210023, China
| | - Pengfei Xia
- College of Electronic and Optical Engineering & College of Microelectronics, Nanjing University of Posts & Telecommunications (NUPT), Nanjing 210023, China
| | - Lingling Deng
- College of Electronic and Optical Engineering & College of Microelectronics, Nanjing University of Posts & Telecommunications (NUPT), Nanjing 210023, China
| | - Yu Duan
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, P. R. China
| | - Kun Cao
- Key Laboratory for Organic Electronics and Information Displays (KLOEID), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications (NUPT), Nanjing 210023, China
| | - Shufen Chen
- Key Laboratory for Organic Electronics and Information Displays (KLOEID), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications (NUPT), Nanjing 210023, China
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Sakata T, Kajiya D, Saitow KI. Brush Printing Creates Polarized Green Fluorescence: 3D Orientation Mapping and Stochastic Analysis of Conductive Polymer Films. ACS APPLIED MATERIALS & INTERFACES 2020; 12:46598-46608. [PMID: 32985860 DOI: 10.1021/acsami.0c08061] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Brush printing is a unique method used to obtain uniaxially oriented films, whereby a polymer solution is brushed onto a substrate. However, there have been only a few reports on the brush-printing method. Here, we report the preparation of a uniaxially oriented film of a green light-emitting conductive polymer, poly(9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT). The fluorescence polarization ratio of the oriented F8BT films was as high as 11.3, and the average orientation factor reached 0.74 ± 0.06. The orientation factor and the torsion angle of F8BT were visualized by two mappings of fluorescence and Raman spectral measurements by confocal spectromicroscopy, respectively. These two x-y mapping data with many pixels (∼750 pixels) were evaluated by x-y-z mapping of the film thickness at a single position and were used to reveal the three-dimensional (3D) orientation mechanism from a stochastic approach. Polarized green fluorescence originates from polymer chains uniaxially oriented along the brush direction. The high orientation for a film thickness < 100 nm is established by shear stress, faster capillary flow, and flow-induced chain extension for a thin solution film on a substrate. The high orientation factor was also demonstrated by a high brushing speed, whereas an optimized brushing speed existed. We found that this optimization is attributed to the property of a non-Newtonian fluid. By applying this brush-printing method to the fabrication of an optoelectrical device, polarized green electroluminescence was preliminarily demonstrated by the OLED assembled from an oriented F8BT film.
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Affiliation(s)
| | - Daisuke Kajiya
- Natural Science Center for Basic Research and Development (N-BARD), Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Ken-Ichi Saitow
- Natural Science Center for Basic Research and Development (N-BARD), Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan
- Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan
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8
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Chikayasu Y, Ohisa S, Takahashi T, Chiba T, Kido J. ZnO/Polyethyleneimine Ethoxylated/Lithium Bis(trifluoromethanesulfonyl)imide for Solution-Processed Electron Injection Layers in Organic Light-Emitting Devices. J PHOTOPOLYM SCI TEC 2019. [DOI: 10.2494/photopolymer.32.577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Yuki Chikayasu
- Graduate School of Organic Materials Science, Yamagata University
| | - Satoru Ohisa
- Graduate School of Organic Materials Science, Yamagata University
| | | | - Takayuki Chiba
- Graduate School of Organic Materials Science, Yamagata University
| | - Junji Kido
- Graduate School of Organic Materials Science, Yamagata University
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9
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Dalla Francesca K, Lenfant S, Laurans M, Volatron F, Izzet G, Humblot V, Methivier C, Guerin D, Proust A, Vuillaume D. Charge transport through redox active [H 7P 8W 48O 184] 33- polyoxometalates self-assembled onto gold surfaces and gold nanodots. NANOSCALE 2019; 11:1863-1878. [PMID: 30637426 DOI: 10.1039/c8nr09377f] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Polyoxometalates (POMs) are redox-active molecular oxides, which attract growing interest for their integration into nano-devices, such as high-density data storage non-volatile memories. In this work, we investigated the electrostatic deposition of the negatively charged [H7P8W48O184]33- POM onto positively charged 8-amino-1-octanethiol self-assembled monolayers (SAMs) preformed onto gold substrates or onto an array of gold nanodots. The ring-shaped [H7P8W48O184]33- POM was selected as an example of large POMs with high charge storage capacity. To avoid the formation of POM aggregates onto the substrates, which would introduce variability in the local electrical properties, special attention has to be paid to the preformed SAM seeding layer, which should itself be deprived of aggregates. Where necessary, rinsing steps were found to be crucial to eliminate these aggregates and to provide uniformly covered substrates for subsequent POM deposition and electrical characterizations. This especially holds for commercially available gold/glass substrates while these rinsing steps were not essential in the case of template stripped gold of very low roughness. Charge transport through the related molecular junctions and nanodot molecule junctions (NMJs) has been probed by conducting-AFM. We analyzed the current-voltage curves with different models: electron tunneling though the SAMs (Simmons model), transition voltage spectroscopy (TVS) method or molecular single energy level mediated transport (Landauer equation) and we discussed the energetics of the molecular junctions. We concluded to an energy level alignment of the alkyl spacer and POM lowest occupied molecular orbitals (LUMOs), probably due to dipolar effects.
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Affiliation(s)
- K Dalla Francesca
- Sorbonne Université, CNRS, Institut Parisien de Chimie Moléculaire, IPCM, 4 Place Jussieu, F-75005 Paris, France.
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10
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Chrzanowski M, Banski M, Sitarek P, Misiewicz J, Podhorodecki A. Quantum-dot light-emitting diode with ultrathin Au electrode embedded in solution-processed phosphomolybdic acid. RSC Adv 2019; 9:10754-10759. [PMID: 35515297 PMCID: PMC9062623 DOI: 10.1039/c9ra01680e] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 04/01/2019] [Indexed: 11/21/2022] Open
Abstract
We proposed to exploit phosphomolybdic acid (PMA) as a cost-efficient MoOx source for combined spin-coating/sputtering/spin-coating deposition of a MoOx/Au/MoOx (MAM) composite electrode. The bottom PMA layer provides perfect wetting conditions for ultrathin Au film sputtering and prevents the formation of gold islands on the glass surface, while the top PMA layer helps to reduce light reflection. By optimizing the thickness of ultrathin Au films and PMA layers, we achieved maximum transmittance of 79% at 550 nm and a sheet resistance of only 22 Ω sq−1 which is comparable to the resistance of ITO substrates (20 Ω sq−1). MAM multilayer was explored both as a transparent electrode and as a hole injection layer (HIL) to eliminate ITO and PEDOT:PSS from solution-processed quantum-dot light-emitting diodes (QLEDs). The fabricated MAM-based QLED shows a peak external quantum efficiency (EQE) of 2.7% and maximum brightness of 12 000 cd m−2 at 7 V. By performing bending tests of the polyethylene (PET) substrate coated with MAM electrode, we demonstrate that it is also a promising candidate for flexible transparent optoelectronics. We proposed to exploit phosphomolybdic acid (PMA) as a cost-efficient MoOx source for combined spin-coating/sputtering/spin-coating deposition of a MoOx/Au/MoOx (MAM) composite electrode.![]()
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Affiliation(s)
- Maciej Chrzanowski
- Department of Experimental Physics
- Wroclaw University of Science and Technology
- 50-370 Wroclaw
- Poland
| | - Mateusz Banski
- Department of Experimental Physics
- Wroclaw University of Science and Technology
- 50-370 Wroclaw
- Poland
| | - Piotr Sitarek
- Department of Experimental Physics
- Wroclaw University of Science and Technology
- 50-370 Wroclaw
- Poland
| | - Jan Misiewicz
- Department of Experimental Physics
- Wroclaw University of Science and Technology
- 50-370 Wroclaw
- Poland
| | - Artur Podhorodecki
- Department of Experimental Physics
- Wroclaw University of Science and Technology
- 50-370 Wroclaw
- Poland
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Fallah Hamidabadi V, Momblona C, Pérez-Del-Rey D, Bahari A, Sessolo M, Bolink HJ. Phosphomolybdic acid as an efficient hole injection material in perovskite optoelectronic devices. Dalton Trans 2019; 48:30-34. [DOI: 10.1039/c8dt03680b] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Phosphomolybdic acid (PMA) is a solution-processable high work function material which can be used as hole-injection interface in perovskite solar cells and LEDs.
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Affiliation(s)
| | | | | | - Ali Bahari
- Department of Physics
- Faculty of Basic Sciences
- University of Mazandaran
- Babolsar 47416-95447
- Iran
| | - Michele Sessolo
- Instituto de Ciencia Molecular
- Universidad de Valencia
- Paterna
- Spain
| | - Henk J. Bolink
- Instituto de Ciencia Molecular
- Universidad de Valencia
- Paterna
- Spain
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12
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Wu Y, Xiao Z, He L, Yang X, Lian Y, Li G, Yang X. Widely applicable phosphomolybdic acid doped poly(9-vinylcarbazole) hole transport layer for perovskite light-emitting devices. RSC Adv 2019; 9:30398-30405. [PMID: 35530213 PMCID: PMC9072163 DOI: 10.1039/c9ra05734j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 09/13/2019] [Indexed: 01/11/2023] Open
Abstract
Perovskite light-emitting devices using a PVK:PMA hole transport layer show robust performance, allowing the wide range selection of antisolvents and hole injection layers.
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Affiliation(s)
- Yanting Wu
- School of Physical Science and Technology
- Southwest University
- Chongqing 400715
- China
| | - Zewu Xiao
- School of Physical Science and Technology
- Southwest University
- Chongqing 400715
- China
| | - Lihong He
- School of Physical Science and Technology
- Southwest University
- Chongqing 400715
- China
| | - Xiaoli Yang
- School of Physical Science and Technology
- Southwest University
- Chongqing 400715
- China
| | - Yajun Lian
- School of Physical Science and Technology
- Southwest University
- Chongqing 400715
- China
| | - Guoqing Li
- School of Physical Science and Technology
- Southwest University
- Chongqing 400715
- China
| | - Xiaohui Yang
- School of Physical Science and Technology
- Southwest University
- Chongqing 400715
- China
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13
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Douvas AM, Tsikritzis D, Tselios C, Haider A, Mougharbel AS, Kortz U, Hiskia A, Coutsolelos AG, Palilis LC, Vasilopoulou M, Kennou S, Argitis P. Multi-electron reduction of Wells-Dawson polyoxometalate films onto metallic, semiconducting and dielectric substrates. Phys Chem Chem Phys 2018; 21:427-437. [PMID: 30534673 DOI: 10.1039/c8cp07101b] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The investigation of conditions allowing multi-electron reduction and reoxidation of polyoxometalate (POM) films onto solid substrates is considered an issue of critical importance for their successful incorporation in electronic devices, different types of sensors and catalytic systems. In the present paper, the rich multi-electron redox chemistry of films of Wells-Dawson ammonium salts, namely (NH4)6P2Mo18O62 and (NH4)6P2W18O62, on top of metallic (Al), semiconducting (ITO) and dielectric (SiO2) substrates under ambient conditions is investigated. The respective Keggin heteropolyacids, H3PMo12O40 and H3PW12O40, are also investigated for comparison. On Al substrates, the Wells-Dawson ammonium salts are found to be significantly more reduced (4-6e-) compared to the respective Keggin heteropolyacids (∼2e-), in accordance with their deeper lying lowest unoccupied molecular orbital (LUMO) level. Subsequent thermal treatment in air results in reoxidation of the initially highly reduced POM films. Similar behavior is found on ITO substrates, but in initially less reduced (2-4e-) Wells-Dawson POM films. On the other hand, on SiO2 substrates, the thermal reduction of (NH4)6P2Mo18O62 film is observed and attributed to the thermal oxidation of ammonium counterions by [P2Mo18O62]6- anions. Overall, the multi-electron reduction of Wells-Dawson ammonium salts onto metallic and semiconducting substrates (Al, ITO) is determined by the relative position of the LUMO level of POMs in relation to the Fermi level of the substrate (i.e. substrate work function) and affected in a synergistic way by the presence of ammonium counterions. In contrast, on dielectric substrates (SiO2) the reduction of Wells-Dawson POMs ((NH4)6P2Mo18O62) is attributed only to the oxidation of ammonium counterions.
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Affiliation(s)
- Antonios M Douvas
- Institute of Nanoscience and Nanotechnology (INN), National Center for Scientific Research (NCSR) "Demokritos", 15341 Agia Paraskevi, Attica, Greece.
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14
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Jiang C, Zou J, Liu Y, Song C, He Z, Zhong Z, Wang J, Yip HL, Peng J, Cao Y. Fully Solution-Processed Tandem White Quantum-Dot Light-Emitting Diode with an External Quantum Efficiency Exceeding 25. ACS NANO 2018; 12:6040-6049. [PMID: 29894158 DOI: 10.1021/acsnano.8b02289] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Solution-processed electroluminescent tandem white quantum-dot light-emitting diodes (TWQLEDs) have the advantages of being low-cost and high-efficiency and having a wide color gamut combined with color filters, making this a promising backlight technology for high-resolution displays. However, TWQLEDs are rarely reported due to the challenge of designing device structures and the deterioration of film morphology with component layers that can be deposited from solutions. Here, we report an interconnecting layer with the optical, electrical, and mechanical properties required for fully solution-processed TWQLED. The optimized TWQLEDs exhibit a state-of-the-art current efficiency as high as 60.4 cd/A and an extremely high external quantum efficiency of 27.3% at a luminance of 100 000 cd/m2. A high color gamut of 124% NTSC 1931 standard can be achieved when combined with commercial color filters. These results represent the highest performance for solution-processed WQLEDs, unlocking the great application potential of TWQLEDs as backlights for new-generation displays.
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Affiliation(s)
- Congbiao Jiang
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , China
| | - Jianhua Zou
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , China
- Guangzhou New Vision Optoelectronic Technology Co., Ltd. , Guangzhou 510730 , China
| | - Yu Liu
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , China
| | - Chen Song
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , China
| | - Zhiwei He
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , China
| | - Zhenji Zhong
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , China
| | - Jian Wang
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , China
| | - Hin-Lap Yip
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , China
| | - Junbiao Peng
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , China
| | - Yong Cao
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , China
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15
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Ohisa S, Kato T, Takahashi T, Suzuki M, Hayashi Y, Koganezawa T, McNeill CR, Chiba T, Pu YJ, Kido J. Conjugated Polyelectrolyte Blend with Polyethyleneimine Ethoxylated for Thickness-Insensitive Electron Injection Layers in Organic Light-Emitting Devices. ACS APPLIED MATERIALS & INTERFACES 2018; 10:17318-17326. [PMID: 29714996 DOI: 10.1021/acsami.8b00752] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Electron injection layers (EILs) based on a simple polymer blend of polyethyleneimine ethoxylated (PEIE) and poly[(9,9-bis(3'-(( N, N-dimethyl)- N-ethylammonium)-propyl)-2,7-fluorene)- alt-2,7-(9,9-dioctylfluorene)] (PFN-Br) can suppress the dependence of organic light-emitting device (OLED) performance on thickness variation compared with single PEIE or PFN-Br EILs. PEIE and PFN-Br were compatible with each other and PFN-Br uniformly mixed in the PEIE matrix. PFN-Br in PEIE formed more fluorene-fluorene pairs than PFN-Br alone. In addition, PEIE:PFN-Br blends reduced the work function (WF) substantially compared with single PEIE or PFN-Br polymer. PEIE:PFN-Br blends were applied to EILs in fluorescent polymer-based OLEDs. Optimized PEIE:PFN-Br blend EIL-based devices presented lower driving voltages and smaller dependences of device performance on EIL thickness than single PEIE or PFN-Br-based devices. These improvements were attributed to electron-transporting fluorene moieties, increased fluorene-fluorene pairs working as channels of electron transport, and the large WF reduction effect of PEIE:PFN-Br blends.
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Affiliation(s)
| | | | | | | | | | - Tomoyuki Koganezawa
- Japan Synchrotron Radiation Research Institute (JASRI), SPring-8 , 1-1-1 Kouto , Sayo , Hyogo 679-5198 , Japan
| | - Christopher R McNeill
- Department of Materials Science and Engineering , Monash University , Wellington Road , Victoria 3800 , Australia
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Liu Y, Jiang C, Song C, Wang J, Mu L, He Z, Zhong Z, Cun Y, Mai C, Wang J, Peng J, Cao Y. Highly Efficient All-Solution Processed Inverted Quantum Dots Based Light Emitting Diodes. ACS NANO 2018; 12:1564-1570. [PMID: 29365251 DOI: 10.1021/acsnano.7b08129] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In all-solution processed inverted quantum dots based light emitting diodes (QLEDs), the solvent erosion on the quantum dot (QD) layer prevents devices from reaching high performance. By employing an orthogonal solvent 1,4-dioxane for the hole transport layer (HTL) poly(9-vinlycarbazole) (PVK), the external quantum efficiencies (EQE) of red QLED is increased 4-fold, while the luminous efficiencies (LE) of blue QLED is enhanced by 25 times, compared to the previous devices' record. To further improve the device efficiency and reduce the efficiency roll-off, solution processed PVK/poly [(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(p-butylphenyl))diphenylamine)] (TFB) double-layer HTL is introduced to facilitate hole injection with stepwise energy level. By reducing the hole injection barrier, the turn-on voltage of QLEDs decreases from 3.4 to 2.7 V for red, from 5.1 to 2.7 V for green, and from 5.3 to 4.1 V for blue. The peak LE reach 22.1 cd/A, 21.4 cd/A, and 1.99 cd/A, while the maximum EQE reach 12.7%, 5.29%, and 5.99%, for red, green, and blue QLEDs, respectively. To the best of our knowledge, the red and blue QLEDs exhibit the best device performance among all the all-solution processed inverted QLEDs. In addition, the blue QLED is the champion among all the inverted QLEDs, including the devices fabricated by thermal evaporation.
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Affiliation(s)
- Yu Liu
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology , Guangzhou 510640, China
| | - Congbiao Jiang
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology , Guangzhou 510640, China
| | - Chen Song
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology , Guangzhou 510640, China
| | - Juanhong Wang
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology , Guangzhou 510640, China
| | - Lan Mu
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology , Guangzhou 510640, China
| | - Zhiwei He
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology , Guangzhou 510640, China
| | - Zhenji Zhong
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology , Guangzhou 510640, China
| | - Yangke Cun
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology , Guangzhou 510640, China
| | - Chaohuang Mai
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology , Guangzhou 510640, China
| | - Jian Wang
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology , Guangzhou 510640, China
| | - Junbiao Peng
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology , Guangzhou 510640, China
| | - Yong Cao
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology , Guangzhou 510640, China
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17
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Ohisa S, Endo K, Kasuga K, Suzuki M, Chiba T, Pu YJ, Kido J. Post-Treatment-Free Solution-Processed Reduced Phosphomolybdic Acid Containing Molybdenum Oxide Units for Efficient Hole-Injection Layers in Organic Light-Emitting Devices. Inorg Chem 2018; 57:1950-1957. [DOI: 10.1021/acs.inorgchem.7b02842] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Satoru Ohisa
- Department of Organic Materials
Science, ‡Research Center for Organic Electronics, and §Frontier Center for Organic Materials, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan
| | - Kohei Endo
- Department of Organic Materials
Science, ‡Research Center for Organic Electronics, and §Frontier Center for Organic Materials, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan
| | - Kosuke Kasuga
- Department of Organic Materials
Science, ‡Research Center for Organic Electronics, and §Frontier Center for Organic Materials, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan
| | - Michinori Suzuki
- Department of Organic Materials
Science, ‡Research Center for Organic Electronics, and §Frontier Center for Organic Materials, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan
| | - Takayuki Chiba
- Department of Organic Materials
Science, ‡Research Center for Organic Electronics, and §Frontier Center for Organic Materials, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan
| | - Yong-Jin Pu
- Department of Organic Materials
Science, ‡Research Center for Organic Electronics, and §Frontier Center for Organic Materials, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan
| | - Junji Kido
- Department of Organic Materials
Science, ‡Research Center for Organic Electronics, and §Frontier Center for Organic Materials, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan
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18
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Chiba T, Pu YJ, Ide T, Ohisa S, Fukuda H, Hikichi T, Takashima D, Takahashi T, Kawata S, Kido J. Addition of Lithium 8-Quinolate into Polyethylenimine Electron-Injection Layer in OLEDs: Not Only Reducing Driving Voltage but Also Improving Device Lifetime. ACS APPLIED MATERIALS & INTERFACES 2017; 9:18113-18119. [PMID: 28497949 DOI: 10.1021/acsami.7b02658] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Solution-processed electron injection layers (EILs) comprising lithium 8-quinolate (Liq) and polyethylenimine ethoxylated (PEIE) are highly effective for enhancing electron injection from ZnO to organic layers and improving device lifetime in organic light-emitting devices (OLEDs). Doping of Liq into PEIE further reduces the work function of zinc oxide (ZnO) by enhancing dipole formation. The intermolecular interaction between Liq and PEIE was elucidated by UV-vis absorption measurement and quantum chemical calculation. The OLEDs with ZnO covered with PEIE:Liq mixture exhibited lower driving voltage than that of the device without Liq. Furthermore, as doping concentration of Liq into PEIE increased, the device lifetime and voltage stability during constant current operation was successively improved.
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Affiliation(s)
- Takayuki Chiba
- Graduate School of Organic Materials Science, Yamagata University , 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan
| | - Yong-Jin Pu
- Graduate School of Organic Materials Science, Yamagata University , 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan
| | - Takahumi Ide
- Graduate School of Organic Materials Science, Yamagata University , 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan
| | - Satoru Ohisa
- Graduate School of Organic Materials Science, Yamagata University , 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan
| | - Hitoshi Fukuda
- Graduate School of Organic Materials Science, Yamagata University , 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan
| | - Tatsuya Hikichi
- Graduate School of Organic Materials Science, Yamagata University , 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan
| | - Dai Takashima
- Graduate School of Organic Materials Science, Yamagata University , 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan
| | - Tatsuya Takahashi
- Graduate School of Organic Materials Science, Yamagata University , 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan
| | - So Kawata
- Graduate School of Organic Materials Science, Yamagata University , 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan
| | - Junji Kido
- Graduate School of Organic Materials Science, Yamagata University , 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan
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Ohisa S, Pu YJ, Takahashi S, Chiba T, Kido J. Inhibition of solution-processed 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile crystallization by mixing additives for hole injection layers in organic light-emitting devices. Polym J 2016. [DOI: 10.1038/pj.2016.92] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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