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Wang Y, Yang D, Zhang H. PEDOT:PSS-Free Quantum-Dot Light-Emitting Diode with Enhanced Efficiency and Stability. ACS APPLIED MATERIALS & INTERFACES 2024; 16:59606-59613. [PMID: 39420653 DOI: 10.1021/acsami.4c13899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2024]
Abstract
Although high-performance quantum-dot light-emitting diodes (QLEDs) have been achieved, their stability is still limited due to the use of unstable PEDOT:PSS as the hole injection layer (HIL). Here, we developed a PEDOT:PSS-free QLED by using a binary PTAA:F4-TCNQ HIL. Because the PTAA, with a highest occupied molecular orbital (HOMO) level of ∼5.20 eV, can facilitate hole injection from ITO to the hole transport layer, and the F4-TCNQ can act as the electron acceptor dopant to improve the hole density and hole mobility of PTAA, the PTAA:F4-TCNQ HIL can exhibit excellent hole injection capability. As a result, the PEDOT:PSS-free QLED can exhibit a high EQE of 24.19% and an impressive brightness of 367,200 cd/m2, which are significantly higher than those of conventional QLEDs. Moreover, due to the improvement of device performance and the removal of PEDOT:PSS, the PEDOT:PSS-free QLED can also exhibit a high T95 operational lifetime of 4206 h at 1000 cd/m2 and an excellent T80 shelf lifetime of 207.41 h at 136400 cd/m2, which are about 1.6- and 3.3-fold those of conventional QLEDs, respectively. We believe that the demonstrated PEDOT:PSS-free QLED, with higher performance and stability, will promote the practical application of QLEDs in displays.
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Affiliation(s)
- Yuanyuan Wang
- State Key Laboratory of Featured Metal Materials and Life-Cycle Safety for Composite Structures, School of Resources, Environments and Materials, Guangxi University, Nanning 530004, China
| | - Dawei Yang
- State Key Laboratory of Featured Metal Materials and Life-Cycle Safety for Composite Structures, School of Resources, Environments and Materials, Guangxi University, Nanning 530004, China
| | - Heng Zhang
- State Key Laboratory of Featured Metal Materials and Life-Cycle Safety for Composite Structures, School of Resources, Environments and Materials, Guangxi University, Nanning 530004, China
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Chen Q, Hu Y, Lin J, Huang J, Gong SL, Xie G. Phenethylammonium bromide interlayer for high-performance red quantum-dot light emitting diodes. NANOSCALE HORIZONS 2024; 9:465-471. [PMID: 38224192 DOI: 10.1039/d3nh00495c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2024]
Abstract
Interfacial modification is vital to boost the performance of colloidal quantum-dot light-emitting diodes (QLEDs). We introduce phenethylammonium bromide (PEABr) as an interlayer to reduce the trap states and exciton quenching at the interface between the emitting layer (EML) with CdSe/ZnS quantum-dots and the electron transport layer (ETL) with ZnMgO. The presence of PEABr separates the EML and the ETL and thus passivates the surface traps of ZnMgO. Moreover, the interfacial modification also alleviates electron injection, leading to more improved carrier injection balance. Consequently, the external quantum efficiency of the PEABr-based red QLED reached 27.6%, which outperformed those of the previously reported devices. Our results indicate that the halide ion salts are promising to balance charge carrier injection and reduce exciton quenching in the QLEDs.
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Affiliation(s)
- Qiyin Chen
- Sauvage Center for Molecular Sciences, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University, Wuhan 430072, China.
- The Institute of Flexible Electronics (Future Technologies), Xiamen University, Xiamen 361005, China
| | - Yun Hu
- Oxford Suzhou Centre for Advanced Research (OSCAR), University of Oxford, Suzhou 215123, China.
| | - Jie Lin
- Oxford Suzhou Centre for Advanced Research (OSCAR), University of Oxford, Suzhou 215123, China.
| | - Jingsong Huang
- Oxford Suzhou Centre for Advanced Research (OSCAR), University of Oxford, Suzhou 215123, China.
| | - Shu-Ling Gong
- Sauvage Center for Molecular Sciences, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University, Wuhan 430072, China.
| | - Guohua Xie
- Sauvage Center for Molecular Sciences, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University, Wuhan 430072, China.
- The Institute of Flexible Electronics (Future Technologies), Xiamen University, Xiamen 361005, China
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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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Yang JH, Jang GP, Kim SY, Chae YB, Lee KH, Moon DG, Kim CK. Highly Efficient All-Solution-Processed Quantum Dot Light-Emitting Diodes Using MoO x Nanoparticle Hole Injection Layer. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2324. [PMID: 37630909 PMCID: PMC10459627 DOI: 10.3390/nano13162324] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 08/09/2023] [Accepted: 08/09/2023] [Indexed: 08/27/2023]
Abstract
This paper presents a study that aims to enhance the performance of quantum dot light-emitting didoes (QLEDs) by employing a solution-processed molybdenum oxide (MoOx) nanoparticle (NP) as a hole injection layer (HIL). The study investigates the impact of varying the concentrations of the MoOx NP layer on device characteristics and delves into the underlying mechanisms that contribute to the observed enhancements. Experimental techniques such as an X-ray diffraction and field-emission transmission electron microscopy were employed to confirm the formation of MoOx NPs during the synthesis process. Ultraviolet photoelectron spectroscopy was employed to analyze the electron structure of the QLEDs. Remarkable enhancements in device performance were achieved for the QLED by employing an 8 mg/mL concentration of MoOx nanoparticles. This configuration attains a maximum luminance of 69,240.7 cd/cm2, a maximum current efficiency of 56.0 cd/A, and a maximum external quantum efficiency (EQE) of 13.2%. The obtained results signify notable progress in comparison to those for QLED without HIL, and studies that utilize the widely used poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) HIL. They exhibit a remarkable enhancements of 59.5% and 26.4% in maximum current efficiency, respectively, as well as significant improvements of 42.7% and 20.0% in maximum EQE, respectively. This study opens up new possibilities for the selection of HIL and the fabrication of solution-processed QLEDs, contributing to the potential commercialization of these devices in the future.
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Affiliation(s)
| | | | | | | | | | | | - Chang-Kyo Kim
- Department of Electronic Materials, Devices and Equipment Engineering, Soonchunhyang University, Asan 31538, Chungnam, Republic of Korea; (J.-H.Y.); (G.-P.J.); (S.-Y.K.); (Y.-B.C.); (K.-H.L.); (D.-G.M.)
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Bottom Contact Metal Oxide Interface Modification Improving the Efficiency of Organic Light Emitting Diodes. MATERIALS 2020; 13:ma13225082. [PMID: 33187216 PMCID: PMC7696400 DOI: 10.3390/ma13225082] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Revised: 11/02/2020] [Accepted: 11/09/2020] [Indexed: 11/17/2022]
Abstract
The performance of solution-processed organic light emitting diodes (OLEDs) is often limited by non-uniform contacts. In this work, we introduce Ni-containing solution-processed metal oxide (MO) interfacial layers inserted between indium tin oxide (ITO) and poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) to improve the bottom electrode contact for OLEDs using the poly(p-phenylene vinylene) (PPV) derivative Super-Yellow (SY) as an emission layer. For ITO/Ni-containing MO/PEDOT:PSS bottom electrode structures we show enhanced wetting properties that result in an improved OLED device efficiency. Best performance is achieved using a Cu-Li co-doped spinel nickel cobaltite [(Cu-Li):NiCo2O4], for which the current efficiency and luminous efficacy of SY OLEDs increased, respectively, by 12% and 11% from the values obtained for standard devices without a Ni-containing MO interface modification between ITO and PEDOT:PSS. The enhanced performance was attributed to the improved morphology of PEDOT:PSS, which consequently increased the hole injection capability of the optimized ITO/(Cu-Li):NiCo2O4/PEDOT:PSS electrode.
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