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Ding T, Song YM, Wang MW, Liu H, Jiang J, Xu JC, Liu HC, Ng KW, Wang SP. Atomic Layer-Deposited Silane Coupling Agent for Interface Passivation of Quantum Dot Light-Emitting Diodes. J Phys Chem Lett 2024; 15:9233-9238. [PMID: 39226074 DOI: 10.1021/acs.jpclett.4c01974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Inserting an insulating layer between the charge transport layer (CTL) and quantum dot emitting layer (QDL) is widely used in improving the performance of quantum dot light-emitting diodes (QLEDs). However, the additional layer inevitably leads to energy loss and joule heat. Herein, a monolayer silane coupling agent is used to modify the said interfaces via the self-limiting adsorption effect. Because the ultrathin layers induce negligible series resistance to the device, they can partially passivate the interfacial defects on the electron transport side and help confine the electrons within the QDL on the hole transport side. These interfacial modifications can not only suppress the nonradiative recombination but also slow down the aging of the hole transport layer. The findings here underline a low-temperature adsorption-based strategy for effective interfacial modification which can be used in any layer-by-layer device structures.
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Affiliation(s)
- Ting Ding
- Institute of Applied Physics and Materials Engineering, University of Macau, Taipa, Macao SAR 999078, China
| | - Yin-Man Song
- Institute of Applied Physics and Materials Engineering, University of Macau, Taipa, Macao SAR 999078, China
| | - Meng-Wei Wang
- Institute of Applied Physics and Materials Engineering, University of Macau, Taipa, Macao SAR 999078, China
| | - Hang Liu
- Institute of Applied Physics and Materials Engineering, University of Macau, Taipa, Macao SAR 999078, China
| | - Jing Jiang
- Institute of Applied Physics and Materials Engineering, University of Macau, Taipa, Macao SAR 999078, China
| | - Jin-Cheng Xu
- Institute of Applied Physics and Materials Engineering, University of Macau, Taipa, Macao SAR 999078, China
| | - Hong-Chao Liu
- Institute of Applied Physics and Materials Engineering, University of Macau, Taipa, Macao SAR 999078, China
| | - Kar-Wei Ng
- Institute of Applied Physics and Materials Engineering, University of Macau, Taipa, Macao SAR 999078, China
| | - Shuang-Peng Wang
- Institute of Applied Physics and Materials Engineering, University of Macau, Taipa, Macao SAR 999078, China
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2
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Samanta K, Deswal P, Alam S, Bhati M, Ivanov SA, Tretiak S, Ghosh D. Ligand Controls Excited Charge Carrier Dynamics in Metal-Rich CdSe Quantum Dots: Computational Insights. ACS NANO 2024; 18:24941-24952. [PMID: 39189799 DOI: 10.1021/acsnano.4c05638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/28/2024]
Abstract
Small metal-rich semiconducting quantum dots (QDs) are promising for solid-state lighting and single-photon emission due to their highly tunable yet narrow emission line widths. Nonetheless, the anionic ligands commonly employed to passivate these QDs exert a substantial influence on the optoelectronic characteristics, primarily owing to strong electron-phonon interactions. In this work, we combine time-domain density functional theory and nonadiabatic molecular dynamics to investigate the excited charge carrier dynamics of Cd28Se17X22 QDs (X = HCOO-, OH-, Cl-, and SH-) at ambient conditions. These chemically distinct but regularly used molecular groups influence the dynamic surface-ligand interfacial interactions in Cd-rich QDs, drastically modifying their vibrational characteristics. The strong electron-phonon coupling leads to substantial transient variations at the band edge states. The strength of these interactions closely depends on the physicochemical characteristics of passivating ligands. Consequently, the ligands largely control the nonradiative recombination rates and emission characteristics in these QDs. Our simulations indicate that Cd28Se17(OH)22 has the fastest nonradiative recombination rate due to the strongest electron-phonon interactions. Conversely, QDs passivated with thiolate or chloride exhibit considerably longer carrier lifetimes and suppressed nonradiative processes. The ligand-controlled electron-phonon interactions further give rise to the broadest and narrowest intrinsic optical line widths for OH and Cl-passivated single QDs, respectively. Obtained computational insights lay the groundwork for designing appropriate passivating ligands on metal-rich QDs, making them suitable for a wide range of applications, from blue LEDs to quantum emitters.
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Affiliation(s)
- Kushal Samanta
- Department of Materials Science and Engineering, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110016, India
| | - Priyanka Deswal
- Department of Physics, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110016, India
| | - Shayeeque Alam
- Department of Materials Science and Engineering, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110016, India
| | - Manav Bhati
- Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Sergei A Ivanov
- Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Sergei Tretiak
- Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Dibyajyoti Ghosh
- Department of Materials Science and Engineering, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110016, India
- Department of Chemistry, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110016, India
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3
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Xie L, Shi J, Wang T, Li Q, Yi YQQ, Zhang Q, Liu Y, Su W, Bae BS, Onwudiwe DC, Lei W, Cui Z, Luscombe CK. A Novel Crosslinked Hole Transport Layer with Enhanced Charge Injection Balance for Highly Efficient Inkjet-Printed Blue Quantum Dot-Based Light-Emitting Diodes. ACS APPLIED MATERIALS & INTERFACES 2024. [PMID: 39231017 DOI: 10.1021/acsami.4c08943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/06/2024]
Abstract
In this work, an efficient and robust hole transport layer (HTL) based on blended poly((9,9-dioctylfluorenyl-2,7-diyl)-alt-(9-(2-ethylhexyl)-carbazole-3,6-diyl)) (PF8Cz) and crosslinkable 3,3'-(9,9-dimethyl-9H-fluorene-2,7-diyl)bis(9-(4-vinylphenyl)-9H-carbazole) (FLCZ-V) is introduced for high-performance and stable blue quantum dot-based light-emitting diodes (QLEDs), wherein FLCZ-V can in situ-crosslink to a continuous network polymer after thermal treatment and the linear polymer PF8CZ becomes intertwined and imprisoned. As a result, the blended HTL shows a high hole mobility (1.27 × 10-4 cm2 V-1 s-1) and gradient HOMO levels (-5.4 eV of PF8CZ and -5.7 eV of FLCZ-V) that can facilitate hole injecting so as to ameliorate the charge balance and, at the same time, achieve better electron-blocking capability that can effectively attenuate HTL decomposition. Meanwhile, the crosslinked blended HTL showed excellent solvent resistance and a high surface energy of 40.34 mN/m, which is favorable to enhance wettability for the deposition of a follow-up layer and attain better interfacial contact. Based on the blended HTL, blue QLEDs were fabricated by both spin-coating and inkjet printing. For the spin-coated blue QLED, a remarkable enhancement of external quantum efficiency (EQE) of 15.5% was achieved. Also, the EQE of the inkjet-printed blue QLED reached 9.2%, which is thus far the best result for the inkjet-printed blue QLED.
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Affiliation(s)
- Liming Xie
- Joint International Research Laboratory of Information Display and Visualization, School of Electronic Science and Engineering, Southeast University, Nanjing 210096, China
- Printable Electronics Research Center, Nano Devices and Materials Division, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu 215123, China
| | - Jinrong Shi
- Printable Electronics Research Center, Nano Devices and Materials Division, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu 215123, China
| | - Ting Wang
- Printable Electronics Research Center, Nano Devices and Materials Division, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu 215123, China
| | - Qing Li
- Joint International Research Laboratory of Information Display and Visualization, School of Electronic Science and Engineering, Southeast University, Nanjing 210096, China
| | - Yuan-Qiu-Qiang Yi
- Printable Electronics Research Center, Nano Devices and Materials Division, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu 215123, China
- pi-Conjugated Polymers Unit, Okinawa Institute of Science and Technology, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa 904-0495, Japan
| | - Qing Zhang
- NANO-X Vacuum Interconnected Nanotech Workstation, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu 215123, China
| | - Yang Liu
- Printable Electronics Research Center, Nano Devices and Materials Division, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu 215123, China
| | - Wenming Su
- Printable Electronics Research Center, Nano Devices and Materials Division, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu 215123, China
| | - Byung Seong Bae
- Department of Electronics & Display Engineering, Hoseo University, Hoseo Ro 79, Asan city, Chungnam 31499, Republic of Korea
| | - Damian Chinedu Onwudiwe
- Department of Chemistry, School of Mathematics and Physical Sciences, Faculty of Natural and Agricultural Sciences, North-West University, Mafikeng Campus, Private Bag X2046, Mmabatho 2735, South Africa
| | - Wei Lei
- Joint International Research Laboratory of Information Display and Visualization, School of Electronic Science and Engineering, Southeast University, Nanjing 210096, China
| | - Zheng Cui
- Printable Electronics Research Center, Nano Devices and Materials Division, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu 215123, China
| | - Christine K Luscombe
- pi-Conjugated Polymers Unit, Okinawa Institute of Science and Technology, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa 904-0495, Japan
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4
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Li B, Yan Z, Song J, Gao Y, Wang L, Yan X, Shen H, Fan F. Origin of the Efficiency Roll-off in Quantum Dot Light-Emitting Diodes: An Electrically Excited Transient Absorption Spectroscopy Study. NANO LETTERS 2024; 24:10650-10655. [PMID: 39158094 DOI: 10.1021/acs.nanolett.4c03024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/20/2024]
Abstract
In situ characterizations of charge injection dynamics, equilibrated concentration, and electric field distributions shed light on the critical mechanisms of quantum dot light-emitting diodes (QD-LEDs). In this work, we developed electrically excited transient absorption spectroscopy, which can provide the above key information, to investigate the efficiency roll-off of QD-LEDs. We found that the average electron populations per QD are low when QD-LEDs exhibit efficiency roll-off, excluding Auger recombination as the main cause. We also revealed that the weak electrical field inside the QD layer under forward biases has a negligible impact on the efficiency. Interestingly, we found that as the voltage increases the electron concentration in the QD layer saturates at very low levels. When combined with the concomitant efficiency roll-off, we propose electron leakage is the main loss at elevated driving voltages. We further demonstrate that increasing the electron confinement potential with the ZnS shell enables us to efficiently mitigate the efficiency roll-off.
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Affiliation(s)
- Bo Li
- CAS Key Laboratory of Microscale Magnetic Resonance and School of Physical Sciences, University of Science and Technology of China, Hefei 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
- Anhui Province Key Laboratory of Scientific Instrument Development and Application, University of Science and Technology of China, Hefei 230026, China
| | - Zhijie Yan
- CAS Key Laboratory of Microscale Magnetic Resonance and School of Physical Sciences, University of Science and Technology of China, Hefei 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
- Anhui Province Key Laboratory of Scientific Instrument Development and Application, University of Science and Technology of China, Hefei 230026, China
| | - Jiaojiao Song
- Key Laboratory for Special Functional Materials of Ministry of Education, National & Local Joint Engineering Research Center for High-efficiency Display and Lighting Technology, Henan University, Kaifeng 475000, China
| | - Yan Gao
- Key Laboratory for Special Functional Materials of Ministry of Education, National & Local Joint Engineering Research Center for High-efficiency Display and Lighting Technology, Henan University, Kaifeng 475000, China
| | - Lei Wang
- Key Laboratory for Special Functional Materials of Ministry of Education, National & Local Joint Engineering Research Center for High-efficiency Display and Lighting Technology, Henan University, Kaifeng 475000, China
| | - Xiaohan Yan
- CAS Key Laboratory of Microscale Magnetic Resonance and School of Physical Sciences, University of Science and Technology of China, Hefei 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
- Anhui Province Key Laboratory of Scientific Instrument Development and Application, University of Science and Technology of China, Hefei 230026, China
| | - Huaibin Shen
- Key Laboratory for Special Functional Materials of Ministry of Education, National & Local Joint Engineering Research Center for High-efficiency Display and Lighting Technology, Henan University, Kaifeng 475000, China
| | - Fengjia Fan
- CAS Key Laboratory of Microscale Magnetic Resonance and School of Physical Sciences, University of Science and Technology of China, Hefei 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
- Anhui Province Key Laboratory of Scientific Instrument Development and Application, University of Science and Technology of China, Hefei 230026, China
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5
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Yan X, Chen C, Wu B, Sun F, Bao H, Tian W, Chang S, Zhong H, Jin S. Probing the Operation of Quantum-Dot Light-Emitting Diodes Using Electrically Pumped Transient Absorption Spectroscopy. J Phys Chem Lett 2024; 15:8593-8599. [PMID: 39141893 DOI: 10.1021/acs.jpclett.4c02127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/16/2024]
Abstract
The quantum-dot light-emitting diode (QLED) is a new generation light emission source that holds great promise for display and lighting applications. Understanding the dynamics of electrons and holes in QLEDs during their operation is crucial for future QLED optimization, but a time-resolved technology capable of characterizing electrons is still lacking. To tackle this challenge, we develop a unique electrically pumped transient absorption (E-TA) spectroscopy to probe the density of electrons in the QD layer with a nanosecond time resolution. The E-TA result provides a comprehensive understanding of the electron dynamics in QLEDs by quantifying the electron injection time after external voltage on, electron release time after external voltage off, and equilibrated electron density (Ne) in the QD layer during device operation. By combining E-TA technology with time-resolved electroluminescence and transient current measurements, we present a comprehensive overview of the dynamics of both electrons and holes in a QLED during operation.
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Affiliation(s)
- Xianchang Yan
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Cuili Chen
- School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Boning Wu
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Fengke Sun
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Hui Bao
- School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Wenming Tian
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Shuai Chang
- Faculty of Materials Science, Shenzhen MSU-BIT University, Shenzhen 518172, China
| | - Haizheng Zhong
- School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Shengye Jin
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
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6
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Zhu X, Luo X, Deng Y, Wei H, Feng Peng, Ying L, Huang F, Hu Y, Jin Y. Doping bilayer hole-transport polymer strategy stabilizing solution-processed green quantum-dot light-emitting diodes. SCIENCE ADVANCES 2024; 10:eado0614. [PMID: 39151002 PMCID: PMC11328901 DOI: 10.1126/sciadv.ado0614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Accepted: 07/11/2024] [Indexed: 08/18/2024]
Abstract
Quantum-dot light-emitting diodes (QLEDs) are solution-processed electroluminescence devices with great potential as energy-saving, large-area, and low-cost display and lighting technologies. Ideally, the organic hole-transport layers (HTLs) in QLEDs should simultaneously deliver efficient hole injection and transport, effective electron blocking, and robust electrochemical stability. However, it is still challenging for a single HTL to fulfill all these stringent criteria. Here, we demonstrate a general design of doping-bilayer polymer-HTL architecture for stabilizing high-efficiency QLEDs. We show that the bilayer HTLs combining the electrochemical-stable polymer and the electron-blocking polymer unexpectedly increase the hole injection barrier. We mitigated the problem by p-doping of the underlying sublayer of the bilayer HTLs. Consequently, green QLEDs with an unprecedented maximum luminance of 1,340,000 cd m-2 and a record-long operational lifetime (T95 lifetime at an initial luminance of 1000 cd m-2 is 17,700 hours) were achieved. The universality of the strategy is examined in various polymer-HTL systems, providing a general route toward high-performance solution-processed QLEDs.
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Affiliation(s)
- Xitong Zhu
- State Key Laboratory of Silicon and Advanced Semiconductor Materials, Key Laboratory of Excited-State Materials of Zhejiang Province, Department of Chemistry, Zhejiang University, Hangzhou 310027, China
| | - Xiao Luo
- State Key Laboratory of Silicon and Advanced Semiconductor Materials, Key Laboratory of Excited-State Materials of Zhejiang Province, Department of Chemistry, Zhejiang University, Hangzhou 310027, China
| | - Yunzhou Deng
- State Key Laboratory of Silicon and Advanced Semiconductor Materials, Key Laboratory of Excited-State Materials of Zhejiang Province, Department of Chemistry, Zhejiang University, Hangzhou 310027, China
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
| | - Huan Wei
- International Science and Technology Innovation Cooperation Base for Advanced Display Technologies of Hunan Province, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Feng Peng
- Dongguan Volt-Amp Optoelectronics Technology Co. Ltd., Dongguan 523808, China
| | - Lei Ying
- Dongguan Volt-Amp Optoelectronics Technology Co. Ltd., Dongguan 523808, China
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China
| | - Fei Huang
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China
| | - Yuanyuan Hu
- International Science and Technology Innovation Cooperation Base for Advanced Display Technologies of Hunan Province, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Yizheng Jin
- State Key Laboratory of Silicon and Advanced Semiconductor Materials, Key Laboratory of Excited-State Materials of Zhejiang Province, Department of Chemistry, Zhejiang University, Hangzhou 310027, China
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7
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Wan H, Jung ED, Zhu T, Park SM, Pina JM, Xia P, Bertens K, Wang YK, Atan O, Chen H, Hou Y, Lee S, Won YH, Kim KH, Hoogland S, Sargent EH. Nickel Oxide Hole Injection Layers for Balanced Charge Injection in Quantum Dot Light-Emitting Diodes. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2402371. [PMID: 38597692 DOI: 10.1002/smll.202402371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Indexed: 04/11/2024]
Abstract
Quantum dot (QD) light-emitting diodes (QLEDs) are promising for next-generation displays, but suffer from carrier imbalance arising from lower hole injection compared to electron injection. A defect engineering strategy is reported to tackle transport limitations in nickel oxide-based inorganic hole-injection layers (HILs) and find that hole injection is able to enhance in high-performance InP QLEDs using the newly designed material. Through optoelectronic simulations, how the electronic properties of NiOx affect hole injection efficiency into an InP QD layer, finding that efficient hole injection depends on lowering the hole injection barrier and enhancing the acceptor density of NiOx is explored. Li doping and oxygen enriching are identified as effective strategies to control intrinsic and extrinsic defects in NiOx, thereby increasing acceptor density, as evidenced by density functional theory calculations and experimental validation. With fine-tuned inorganic HIL, InP QLEDs exhibit a luminance of 45 200 cd m-2 and an external quantum efficiency of 19.9%, surpassing previous inorganic HIL-based QLEDs. This study provides a path to designing inorganic materials for more efficient and sustainable lighting and display technologies.
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Affiliation(s)
- Haoyue Wan
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario, M5S 1A4, Canada
| | - Eui Dae Jung
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario, M5S 1A4, Canada
| | - Tong Zhu
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario, M5S 1A4, Canada
| | - So Min Park
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario, M5S 1A4, Canada
| | - Joao M Pina
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario, M5S 1A4, Canada
| | - Pan Xia
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario, M5S 1A4, Canada
| | - Koen Bertens
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario, M5S 1A4, Canada
| | - Ya-Kun Wang
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario, M5S 1A4, Canada
| | - Ozan Atan
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario, M5S 1A4, Canada
| | - Haijie Chen
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario, M5S 1A4, Canada
| | - Yi Hou
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario, M5S 1A4, Canada
| | - Seungjin Lee
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario, M5S 1A4, Canada
| | - Yu-Ho Won
- Samsung Advanced Institute of Technology, Samsung Electronics, Suwon, 16678, Republic of Korea
| | - Kwang-Hee Kim
- Samsung Advanced Institute of Technology, Samsung Electronics, Suwon, 16678, Republic of Korea
| | - Sjoerd Hoogland
- 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
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8
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Hou D, Lv P, Niu W, Guan Z, Wang L, Zhao J, Li X, Ye H, Tang A. Controllable Synthesis of Cadmium-Free Blue-Emitting Cu-Ga-Zn-S-Based Nanocrystals for Solution-Processed Quantum-Dot Light-Emitting Diodes. J Phys Chem Lett 2024; 15:7516-7523. [PMID: 39023013 DOI: 10.1021/acs.jpclett.4c01527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
The utility of semiconductor nanocrystals (NCs) in light-emitting diodes (LED) has shown great potential in the field of display, whereas the challenge remains in developing efficient and stable cadmium-free blue-emitting LED devices due to the poor photophysical properties of blue-emitting NCs. Herein, we develop a controllable synthesis of Cu-Ga-Zn-S (CGZS) semiconductor NCs that show blue light emission with a relative photoluminescence quantum yield exceeding 90%. Furthermore, we have successfully fabricated a solution-processed quantum-dot LED (QLED) using CGZS NCs, achieving a notable maximum external quantum efficiency (EQE) of 1.00% at a luminance of 100 cd/m2. Our work lays a foundational framework for advancing cadmium-free blue-emitting QLEDs and facilitates the development of quantum dot electroluminescent panchromatic displays.
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Affiliation(s)
- Danxing Hou
- Key Laboratory of Luminescence and Optical Information, Ministry of Education, School of Science, Beijing Jiaotong University, Beijing 100044, China
| | - Peiwen Lv
- Key Laboratory of Luminescence and Optical Information, Ministry of Education, School of Science, Beijing Jiaotong University, Beijing 100044, China
| | - Wentao Niu
- Key Laboratory of Luminescence and Optical Information, Ministry of Education, School of Science, Beijing Jiaotong University, Beijing 100044, China
| | - Zhongyuan Guan
- Key Laboratory of Luminescence and Optical Information, Ministry of Education, School of Science, Beijing Jiaotong University, Beijing 100044, China
| | - Lijin Wang
- Key Laboratory of Luminescence and Optical Information, Ministry of Education, School of Science, Beijing Jiaotong University, Beijing 100044, China
| | - Jinxing Zhao
- Key Laboratory of Luminescence and Optical Information, Ministry of Education, School of Science, Beijing Jiaotong University, Beijing 100044, China
| | - Xu Li
- Hebei Key Laboratory of Optic-electronic Information and Materials, College of Physics Science and Technology, Hebei University, Baoding 071002, China
| | - Haihang Ye
- Center for Intelligent Medical Equipment and Devices, Institute for Innovative Medical Devices, Suzhou Institute for Advanced Research, University of Science and Technology of China, Suzhou, Jiangsu 215123, China
- Key Laboratory of Precision and Intelligent Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Aiwei Tang
- Key Laboratory of Luminescence and Optical Information, Ministry of Education, School of Science, Beijing Jiaotong University, Beijing 100044, China
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9
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Sun X, Chen X, Sun X, Xie J, Zhou L, Chen S. Improved Charge Injection Balance in Quantum Dot Light-Emitting Diodes through Interface Texture. J Phys Chem Lett 2024; 15:7199-7205. [PMID: 38968573 DOI: 10.1021/acs.jpclett.4c01486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/07/2024]
Abstract
The existing methods to improve the charge balance of quantum dot light-emitting diodes (QLEDs) rely on energy-level matching, but these approaches have been limited by material availability and Fermi-level pinning. Here, we propose a solution that does not require changes to the materials' electronic properties. By using nanoimprinting technology to texture the interface between the hole-transporting layer (HTL) and colloidal quantum dot (CQD) layer, we can increase the HTL-CQD contact area. This significantly enhances the hole injection rate while keeping the electron injection rate essentially unchanged. Compared with the conventional planar structure, QLEDs with textured HTL exhibit lower luminance threshold voltage, significantly higher external quantum efficiency at low bias voltages, improved operational stability, and a similar Lambertian factor. Comprehensive measurements confirm that the HTL-CQD interface texture allows more efficient hole injection into CQDs to occur under lower bias, resulting in less CQD charging and more efficient exciton recombination.
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Affiliation(s)
- Xuhao Sun
- Suzhou Key Laboratory of Novel Semiconductor-optoelectronics Materials and Devices, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, Jiangsu, China
| | - Xingtong Chen
- Suzhou Key Laboratory of Novel Semiconductor-optoelectronics Materials and Devices, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, Jiangsu, China
| | - Xiaojuan Sun
- Suzhou Key Laboratory of Novel Semiconductor-optoelectronics Materials and Devices, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, Jiangsu, China
| | - Jiachen Xie
- Suzhou Key Laboratory of Novel Semiconductor-optoelectronics Materials and Devices, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, Jiangsu, China
| | - Luohe Zhou
- Suzhou Key Laboratory of Novel Semiconductor-optoelectronics Materials and Devices, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, Jiangsu, China
| | - Song Chen
- Suzhou Key Laboratory of Novel Semiconductor-optoelectronics Materials and Devices, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, Jiangsu, China
- Jiangsu Key Laboratory of Advanced Negative Carbon Technologies, Soochow University, Suzhou 215123, Jiangsu, China
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10
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Huo X, Xie Y, Wang X, Zhang L, Yang M. Reduction reactions at the interface between CdS quantum dot and Z-type ligands driven by electron injection in the electroluminescent processes. J Chem Phys 2024; 161:024304. [PMID: 38984958 DOI: 10.1063/5.0196243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Accepted: 06/24/2024] [Indexed: 07/11/2024] Open
Abstract
The efficient and stable electroluminescence of quantum dots (QDs) is of great importance in their applications in new display technologies. The short service life of blue QDs, however, hinders their development and commercialization. Different mechanisms have been proposed for the destabilization of QDs in electroluminescent processes. Based on real-time time-dependent density functional theory studies on the QD models covered by Z-type ligands (XAc2, X = Cd, Zn, Mg), the structural evolution is simulated to reveal the mechanism of the reduction reactions induced by electron injection. Our simulations reproduce the experimental observations that the reduction reactions occur at the QD-ligand interface, and the reduced Cd atom is almost in a zero valence state. However, different sites are predicted for the reactions in which the surface metal atom of the QD instead of the metal atom in the ligands is reduced. As a result, one of the arms of the chelate ligand leaves the QD, which tends to cause damage to its electroluminescent performance. Our findings contribute to a mechanistic understanding of the reduction reactions that occurred at the QD-ligand interface.
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Affiliation(s)
- Xiangyu Huo
- Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China
| | - Yujuan Xie
- School of Science, Westlake University, Hangzhou 310030, China
| | - Xian Wang
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Li Zhang
- Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China
| | - Mingli Yang
- Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China
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11
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Yang Q, Chung K, Liu X, Sun L, Han J, Yang Y, Chen T, Shi W, Xu B. Confined Space Dual-Type Quantum Dots for High-Rate Electrochemical Energy Storage. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2401375. [PMID: 38747977 DOI: 10.1002/adma.202401375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 05/10/2024] [Indexed: 05/21/2024]
Abstract
Owing to the quantum size effect and high redox activity, quantum dots (QDs) play very essential roles toward electrochemical energy storage. However, it is very difficult to obtain different types and uniformly dispersed high-active QDs in a stable conductive microenvironment, because QDs prepared by traditional methods are mostly dissolved in solution or loaded on the surface of other semiconductors. Herein, dual-type semiconductor QDs (Co9S8 and CdS) are skillfully constructed within the interlayer of ultrathin-layered double hydroxides. In particular, the expandable interlayer provides a very suitable confined space for the growth and uniform dispersion of QDs, where Co9S8 originates from in situ transformation of cobalt atoms in laminate and CdS is generated from interlayer pre-embedding Cd2+. Meanwhile, XAFS and GGA+U calculations are employed to explore and prove the mechanism of QDs formation and energy storage characteristics as compared to surface loading QDs. Significantly, the hybrid supercapacitors achieve a high energy density of 329.2 µWh cm-2, capacitance retention of 99.1%, and coulomb efficiency of 96.9% after 22 000 cycles, which is superior to the reported QDs-based supercapacitors. These findings provide unique insights for designing and developing stable, ordered, and highly active QDs.
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Affiliation(s)
- Qingjun Yang
- Nanotechnology Center, School of Fashion and Textiles, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, 999077, P. R. China
| | - KingYan Chung
- Nanotechnology Center, School of Fashion and Textiles, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, 999077, P. R. China
| | - Xinlong Liu
- Nanotechnology Center, School of Fashion and Textiles, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, 999077, P. R. China
| | - Lin Sun
- School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, 212013, P. R. China
| | - Jing Han
- Nanotechnology Center, School of Fashion and Textiles, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, 999077, P. R. China
| | - Yujue Yang
- Nanotechnology Center, School of Fashion and Textiles, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, 999077, P. R. China
| | - Tiandi Chen
- Nanotechnology Center, School of Fashion and Textiles, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, 999077, P. R. China
| | - Weidong Shi
- School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, 212013, P. R. China
| | - Bingang Xu
- Nanotechnology Center, School of Fashion and Textiles, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, 999077, P. R. China
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12
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Li M, Li R, Wu L, Lin X, Xia X, Ao Z, Sun X, Chen X, Chen S. Ultrabright and stable top-emitting quantum-dot light-emitting diodes with negligible angular color shift. Nat Commun 2024; 15:5161. [PMID: 38886405 PMCID: PMC11183122 DOI: 10.1038/s41467-024-49574-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 06/11/2024] [Indexed: 06/20/2024] Open
Abstract
Top emission can enhance luminance, color purity, and panel-manufacturing compatibility for emissive displays. Still, top-emitting quantum-dot light-emitting diodes (QLEDs) suffer from poor stability, low light outcoupling, and non-negligible viewing-angle dependence because, for QLEDs with non-red emission, the electrically optimum device structure is incompatible with single-mode optical microcavity. Here, we demonstrate that by improving the way of determining reflection penetration depths and creating refractive-index-lowering processes, the issues faced by green QLEDs can be overcome. This leads to advanced device performance, including a luminance exceeding 1.6 million nits, a current efficiency of 204.2 cd A-1, and a T95 operational lifetime of 15,600 hours at 1000 nits. Meanwhile, our design does not compromise light outcoupling as it offers an external quantum efficiency of 29.2% without implementing light extraction methods. Lastly, an angular color shift of Δu'v' = 0.0052 from 0° to 60° is achieved by narrowing the emission linewidth of quantum dots.
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Affiliation(s)
- Mengqi Li
- Suzhou Key Laboratory of Novel Semiconductor-optoelectronics Materials and Devices, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, Jiangsu, China
| | - Rui Li
- Suzhou Key Laboratory of Novel Semiconductor-optoelectronics Materials and Devices, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, Jiangsu, China
| | - Longjia Wu
- TCL Corporate Research, 1001 Zhongshan Park Road, Nanshan District, Shenzhen, 518067, Guangdong, China
| | - Xiongfeng Lin
- TCL Corporate Research, 1001 Zhongshan Park Road, Nanshan District, Shenzhen, 518067, Guangdong, China
| | - Xueqing Xia
- Suzhou Key Laboratory of Novel Semiconductor-optoelectronics Materials and Devices, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, Jiangsu, China
| | - Zitong Ao
- TCL Corporate Research, 1001 Zhongshan Park Road, Nanshan District, Shenzhen, 518067, Guangdong, China
| | - Xiaojuan Sun
- Suzhou Key Laboratory of Novel Semiconductor-optoelectronics Materials and Devices, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, Jiangsu, China
| | - Xingtong Chen
- Suzhou Key Laboratory of Novel Semiconductor-optoelectronics Materials and Devices, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, Jiangsu, China
| | - Song Chen
- Suzhou Key Laboratory of Novel Semiconductor-optoelectronics Materials and Devices, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, Jiangsu, China.
- Jiangsu Key Laboratory of Advanced Negative Carbon Technologies, Soochow University, Suzhou, 215123, Jiangsu, China.
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13
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Chen L, Li D, Wang A, Guo W, Su X, Shang J, Du W, Liu S, Ma Z. Negative corona discharge strategy for efficient quantum dot light-emitting diodes. OPTICS LETTERS 2024; 49:3392-3395. [PMID: 38875628 DOI: 10.1364/ol.515282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 05/24/2024] [Indexed: 06/16/2024]
Abstract
In colloid quantum dot light-emitting diodes (QLEDs), the control of interface states between ZnO and quantum dots (QDs) plays a vital role. We present a straightforward and efficient method using a negative corona discharge to modify the QD film, creating a dipole moment at the interface of QDs and magnesium-doped ZnO (ZnMgO) for balanced charge carrier distribution within the QDs. This process boosts external quantum efficiencies in red, green, and blue QLEDs to 17.71%, 14.53%, and 9.04% respectively. Notably, optimized devices exhibit significant enhancements, especially at lower brightness levels (1000 to 10,000 cd·m-2), vital for applications in mobile displays, TV screens, and indoor lighting.
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14
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Yuan C, Chen Z, Tian F, Chen S. Very Stable and Efficient Tandem Quantum-Dot Light-Emitting Diodes Enabled by IZO-Based Interconnecting Layers. NANO LETTERS 2024. [PMID: 38832838 DOI: 10.1021/acs.nanolett.4c02021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2024]
Abstract
Theoretically, tandem quantum-dot light-emitting diodes (QLEDs) hold great promise for achieving both high efficiency and high stability in display applications. However, in practice, their operational stability remains considerably inferior to that of state-of-the-art devices. In this study, we developed a new tandem structure with optimal electrical and optical performance to simultaneously improve the efficiency and stability of tandem QLEDs. Electrically, upon development of a barrier-free interconnecting layer enabled by an indium-zinc oxide bridging layer and a conductive ZnMgO layer, the driving voltage of the tandem QLEDs is remarkably reduced. Optically, upon development of a top-emitting structure and optimization of the cavity length guided by a theoretical simulation, a maximum light extraction efficiency is achieved. As a result, the red tandem QLEDs exhibit a maximum external quantum efficiency of 49.01% and a T95 lifetime at 1000 cd/m2 of >50 000 h, making them one of the most efficient and stable QLEDs ever reported.
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Affiliation(s)
- Cuixia Yuan
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen 518055, P. R. China
| | - Zinan Chen
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen 518055, P. R. China
| | - Fengshou Tian
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen 518055, P. R. China
| | - Shuming Chen
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen 518055, P. R. China
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15
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Sun SQ, Tai JW, He W, Yu YJ, Feng ZQ, Sun Q, Tong KN, Shi K, Liu BC, Zhu M, Wei G, Fan J, Xie YM, Liao LS, Fung MK. Enhancing Light Outcoupling Efficiency via Anisotropic Low Refractive Index Electron Transporting Materials for Efficient Perovskite Light-Emitting Diodes. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2400421. [PMID: 38430204 DOI: 10.1002/adma.202400421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 02/25/2024] [Indexed: 03/03/2024]
Abstract
Thanks to the extensive efforts toward optimizing perovskite crystallization properties, high-quality perovskite films with near-unity photoluminescence quantum yield are successfully achieved. However, the light outcoupling efficiency of perovskite light-emitting diodes (PeLEDs) is impeded by insufficient light extraction, which poses a challenge to the further advancement of PeLEDs. Here, an anisotropic multifunctional electron transporting material, 9,10-bis(4-(2-phenyl-1H-benzo[d]imidazole-1-yl)phenyl) anthracene (BPBiPA), with a low extraordinary refractive index (ne) and high electron mobility is developed for fabricating high-efficiency PeLEDs. The anisotropic molecular orientations of BPBiPA can result in a low ne of 1.59 along the z-axis direction. Optical simulations show that the low ne of BPBiPA can effectively mitigate the surface plasmon polariton loss and enhance the photon extraction efficiency in waveguide mode, thereby improving the light outcoupling efficiency of PeLEDs. In addition, the high electron mobility of BPBiPA can facilitate balanced carrier injection in PeLEDs. As a result, high-efficiency green PeLEDs with a record external quantum efficiency of 32.1% and a current efficiency of 111.7 cd A-1 are obtained, which provides new inspirations for the design of electron transporting materials for high-performance PeLEDs.
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Affiliation(s)
- Shuang-Qiao Sun
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, Jiangsu, 215123, P. R. China
| | - Jing-Wen Tai
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, Jiangsu, 215123, P. R. China
| | - Wei He
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, Jiangsu, 215123, P. R. China
| | - You-Jun Yu
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, Jiangsu, 215123, P. R. China
| | - Zi-Qi Feng
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, Jiangsu, 215123, P. R. China
| | - Qi Sun
- Macau Institute of Materials Science and Engineering (MIMSE), MUST-SUDA Joint Research Center for Advanced Functional Materials, Zhuhai MUST Science and Technology Research Institute, Macau University of Science and Technology, Taipa, Macau, 999078, P. R. China
| | - Kai-Ning Tong
- Institute of Materials Science, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, Guangdong, 518055, P. R. China
| | - Kefei Shi
- Institute of Materials Science, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, Guangdong, 518055, P. R. China
| | - Bo-Chen Liu
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, Jiangsu, 215123, P. R. China
| | - Min Zhu
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, Jiangsu, 215123, P. R. China
| | - Guodan Wei
- Institute of Materials Science, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, Guangdong, 518055, P. R. China
| | - Jian Fan
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, Jiangsu, 215123, P. R. China
| | - Yue-Min Xie
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, Jiangsu, 215123, P. R. China
- Jiangsu Key Laboratory of Advanced Negative Carbon Technologies, Soochow University, Suzhou, Jiangsu, 215123, P.R. China
| | - Liang-Sheng Liao
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, Jiangsu, 215123, P. R. China
- Macau Institute of Materials Science and Engineering (MIMSE), MUST-SUDA Joint Research Center for Advanced Functional Materials, Zhuhai MUST Science and Technology Research Institute, Macau University of Science and Technology, Taipa, Macau, 999078, P. R. China
| | - Man-Keung Fung
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, Jiangsu, 215123, P. R. China
- Macau Institute of Materials Science and Engineering (MIMSE), MUST-SUDA Joint Research Center for Advanced Functional Materials, Zhuhai MUST Science and Technology Research Institute, Macau University of Science and Technology, Taipa, Macau, 999078, P. R. China
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16
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Zhou T, Wang T, Bai J, Liu S, Zhang H, Xie W, Ji W. High-Performance Tandem Quantum-Dot Light-Emitting Diodes Based on Bulk-Heterojunction-Like Charge-Generation Layers. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2313888. [PMID: 38488320 DOI: 10.1002/adma.202313888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 03/06/2024] [Indexed: 03/23/2024]
Abstract
In this study, the fundamental but previously overlooked factors of charge generation efficiency and light extraction efficiency (LEE) are explored and collaboratively optimized in tandem quantum-dot light-emitting diodes (QLEDs). By spontaneously forming a microstructured interface, a bulk-heterojunction-like charge-generation layer composed of a poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)/ZnO bilayer is fabricated and an ideal charge-generation efficiency surpassing 115% is obtained. The coupling strength of the waveguide mode for the top unit and the plasmon polariton loss for the bottom unit are highly suppressed using precise thickness control, which increases the LEE of the tandem devices. The red tandem QLED achieves an exceptionally low turn-on voltage for electroluminescence at 4.0 V and outstanding peak external quantum efficiency of 42.9%. The ultralow turn-on voltage originates from the sequential electroluminescence turn-on of the two emissive units of the tandem QLED. Benefiting from its unique electroluminescent features, an easily fabricated optical-electrical dual anti-counterfeiting display is built by combining a dichromatic tandem QLED with masking technology.
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Affiliation(s)
- Taiying Zhou
- Key Lab of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University, Changchun, 130012, China
| | - Ting Wang
- Key Laboratory of Functional Materials Physics and Chemistry of the Ministry of Education, Jilin Normal University, Changchun, 130103, China
| | - Jialin Bai
- Key Lab of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University, Changchun, 130012, China
| | - Shihao Liu
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun, 130012, China
| | - Hanzhuang Zhang
- Key Lab of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University, Changchun, 130012, China
| | - Wenfa Xie
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun, 130012, China
| | - Wenyu Ji
- Key Lab of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University, Changchun, 130012, China
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17
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Fan J, Han C, Yang G, Song B, Xu R, Xiang C, Zhang T, Qian L. Recent Progress of Quantum Dots Light-Emitting Diodes: Materials, Device Structures, and Display Applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024:e2312948. [PMID: 38813832 DOI: 10.1002/adma.202312948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 04/05/2024] [Indexed: 05/31/2024]
Abstract
Colloidal quantum dots (QDs), as a class of 0D semiconductor materials, have generated widespread interest due to their adjustable band gap, exceptional color purity, near-unity quantum yield, and solution-processability. With decades of dedicated research, the potential applications of quantum dots have garnered significant recognition in both the academic and industrial communities. Furthermore, the related quantum dot light-emitting diodes (QLEDs) stand out as one of the most promising contenders for the next-generation display technologies. Although QD-based color conversion films are applied to improve the color gamut of existing display technologies, the broader application of QLED devices remains in its nascent stages, facing many challenges on the path to commercialization. This review encapsulates the historical discovery and subsequent research advancements in QD materials and their synthesis methods. Additionally, the working mechanisms and architectural design of QLED prototype devices are discussed. Furthermore, the review surveys the latest advancements of QLED devices within the display industry. The narrative concludes with an examination of the challenges and perspectives of QLED technology in the foreseeable future.
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Affiliation(s)
- Junpeng Fan
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, P. R. China
- Laboratory of Advanced Nano-Optoelectronic Materials and Devices, Qianwan Institute of CNITECH, Ningbo, 315000, P. R. China
| | - Changfeng Han
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, P. R. China
- Laboratory of Advanced Nano-Optoelectronic Materials and Devices, Qianwan Institute of CNITECH, Ningbo, 315000, P. R. China
| | - Guojian Yang
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, P. R. China
- Laboratory of Advanced Nano-Optoelectronic Materials and Devices, Qianwan Institute of CNITECH, Ningbo, 315000, P. R. China
| | - Bin Song
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, P. R. China
- Department of Materials Science and Engineering, Xiamen University, Xiamen, 361005, P. R. China
| | - Rui Xu
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, P. R. China
- Department of Mechanical, Materials and Manufacturing Engineering, University of Nottingham Ningbo China, Ningbo, 315100, P. R. China
| | - Chaoyu Xiang
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, P. R. China
- Laboratory of Advanced Nano-Optoelectronic Materials and Devices, Qianwan Institute of CNITECH, Ningbo, 315000, P. R. China
| | - Ting Zhang
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, P. R. China
- Laboratory of Advanced Nano-Optoelectronic Materials and Devices, Qianwan Institute of CNITECH, Ningbo, 315000, P. R. China
| | - Lei Qian
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, P. R. China
- Laboratory of Advanced Nano-Optoelectronic Materials and Devices, Qianwan Institute of CNITECH, Ningbo, 315000, P. R. China
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18
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Feng Y, Li H, Zhu M, Gao Y, Cai Q, Lu G, Dai X, Ye Z, He H. Nucleophilic Reaction-Enabled Chloride Modification on CsPbI 3 Quantum Dots for Pure Red Light-Emitting Diodes with Efficiency Exceeding 26 . Angew Chem Int Ed Engl 2024; 63:e202318777. [PMID: 38258990 DOI: 10.1002/anie.202318777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Indexed: 01/24/2024]
Abstract
High-performance pure red perovskite light-emitting diodes (PeLEDs) with an emission wavelength shorter than 650 nm are ideal for wide-color-gamut displays, yet remain an unprecedented challenge to progress. Mixed-halide CsPb(Br/I)3 emitter-based PeLEDs suffer spectral stability induced by halide phase segregation and CsPbI3 quantum dots (QDs) suffer from a compromise between emission wavelength and electroluminescence efficiency. Here, we demonstrate efficient pure red PeLEDs with an emission centered at 638 nm based on PbClx -modified CsPbI3 QDs. A nucleophilic reaction that releases chloride ions and manipulates the ligand equilibrium of the colloidal system is developed to synthesize the pure red emission QDs. The comprehensive structural and spectroscopic characterizations evidence the formation of PbClx outside the CsPbI3 QDs, which regulates exciton recombination and prevents the exciton from dissociation induced by surface defects. In consequence, PeLEDs based on PbClx -modified CsPbI3 QDs with superior optoelectronic properties demonstrate stable electroluminescence spectra at high driving voltages, a record external quantum efficiency of 26.1 %, optimal efficiency roll-off of 16.0 % at 1000 cd m-2 , and a half lifetime of 7.5 hours at 100 cd m-2 , representing the state-of-the-art pure red PeLEDs. This work provides new insight into constructing the carrier-confined structure on perovskite QDs for high-performance PeLEDs.
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Affiliation(s)
- Yifeng Feng
- School of Materials Science and Engineering, State Key Laboratory of Silicon and Advanced Semiconductor Materials, Zhejiang University, Hangzhou, 310027, China
| | - Hongjin Li
- School of Materials Science and Engineering, State Key Laboratory of Silicon and Advanced Semiconductor Materials, Zhejiang University, Hangzhou, 310027, China
| | - Meiyi Zhu
- School of Materials Science and Engineering, State Key Laboratory of Silicon and Advanced Semiconductor Materials, Zhejiang University, Hangzhou, 310027, China
- Wenzhou Key Laboratory of Novel Optoelectronic and Nano Materials and Engineering Research Centre of Zhejiang Province, Institute of Wenzhou, Zhejiang University, Wenzhou, 325006, China
| | - Yun Gao
- School of Materials Science and Engineering, State Key Laboratory of Silicon and Advanced Semiconductor Materials, Zhejiang University, Hangzhou, 310027, China
| | - Qiuting Cai
- School of Materials Science and Engineering, State Key Laboratory of Silicon and Advanced Semiconductor Materials, Zhejiang University, Hangzhou, 310027, China
| | - Guochao Lu
- School of Materials Science and Engineering, State Key Laboratory of Silicon and Advanced Semiconductor Materials, Zhejiang University, Hangzhou, 310027, China
| | - Xingliang Dai
- School of Materials Science and Engineering, State Key Laboratory of Silicon and Advanced Semiconductor Materials, Zhejiang University, Hangzhou, 310027, China
- Wenzhou Key Laboratory of Novel Optoelectronic and Nano Materials and Engineering Research Centre of Zhejiang Province, Institute of Wenzhou, Zhejiang University, Wenzhou, 325006, China
- Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering, Shanxi, 030000, China
| | - Zhizhen Ye
- School of Materials Science and Engineering, State Key Laboratory of Silicon and Advanced Semiconductor Materials, Zhejiang University, Hangzhou, 310027, China
- Wenzhou Key Laboratory of Novel Optoelectronic and Nano Materials and Engineering Research Centre of Zhejiang Province, Institute of Wenzhou, Zhejiang University, Wenzhou, 325006, China
- Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering, Shanxi, 030000, China
| | - Haiping He
- School of Materials Science and Engineering, State Key Laboratory of Silicon and Advanced Semiconductor Materials, Zhejiang University, Hangzhou, 310027, China
- Wenzhou Key Laboratory of Novel Optoelectronic and Nano Materials and Engineering Research Centre of Zhejiang Province, Institute of Wenzhou, Zhejiang University, Wenzhou, 325006, China
- Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering, Shanxi, 030000, China
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19
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Sun X, Chen X, Li X, Xie J, Lin X, Shen Q, Wu L, Chen S. Hole-Injection-Barrier Effect on the Degradation of Blue Quantum-Dot Light-Emitting Diodes. ACS NANO 2024. [PMID: 38329720 DOI: 10.1021/acsnano.3c12840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Inefficient hole injection presents a major challenge in achieving stable and commercially viable solution-processed blue electroluminescent devices. Here, we conduct an in-depth study on quantum-dot light-emitting diodes (QLEDs) to understand how the energy levels of common electrodes and hole-transporting layers (HTL) affect device degradation. Our experimental findings reveal a design rule that may seem nonintuitive: combining an electrode and HTL with matched energy levels is most effective in preventing voltage rise and irreversible luminance decay, even though it causes a significant energy offset between the HTL and emissive quantum dots. Using an iterative electrostatic model, we discover that the positive outcomes, including a T95 lifetime of 109 h (luminance = 1000 nits, CIE-y = 0.087), are due to the enhanced p-type doping in the HTL rather than the assumed reduction in barrier heights. Furthermore, our modified hole injection dynamics theory, which considers distributed density-of-states, shows that the increased HTL/quantum-dot energy offset is not a primary concern because the effective barrier height is significantly lower than conventionally assumed. Following this design rule, we expect device stability to be enhanced considerably.
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Affiliation(s)
- Xiaojuan Sun
- Suzhou Key Laboratory of Novel Semiconductor-Optoelectronics Materials and Devices, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, Jiangsu, China
| | - Xingtong Chen
- Suzhou Key Laboratory of Novel Semiconductor-Optoelectronics Materials and Devices, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, Jiangsu, China
| | - Xinrui Li
- Suzhou Key Laboratory of Novel Semiconductor-Optoelectronics Materials and Devices, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, Jiangsu, China
| | - Jiachen Xie
- Suzhou Key Laboratory of Novel Semiconductor-Optoelectronics Materials and Devices, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, Jiangsu, China
| | - Xiongfeng Lin
- TCL Corporate Research, 1001 Zhongshan Park Road, Nanshan District, Shenzhen 518067, Guangdong, China
| | - Qi Shen
- Suzhou Key Laboratory of Novel Semiconductor-Optoelectronics Materials and Devices, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, Jiangsu, China
| | - Longjia Wu
- TCL Corporate Research, 1001 Zhongshan Park Road, Nanshan District, Shenzhen 518067, Guangdong, China
| | - Song Chen
- Suzhou Key Laboratory of Novel Semiconductor-Optoelectronics Materials and Devices, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, Jiangsu, China
- Jiangsu Key Laboratory of Advanced Negative Carbon Technologies, Soochow University, Suzhou 215123, Jiangsu, China
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20
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Cai F, Li M, Zhang H, Wang Y, Li Z, Tu Y, Aldamasy MH, Jiang X, Hou B, Wang S, Du Z. Interfacial Passivation Engineering for Highly Efficient Quantum Dot Light-Emitting Diodes via Aromatic Amine-Functionalized Dipole Molecules. NANO LETTERS 2024; 24:1594-1601. [PMID: 38134416 DOI: 10.1021/acs.nanolett.3c04229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2023]
Abstract
Blue quantum dot (QD) light-emitting diodes (QLEDs) exhibit unsatisfactory operational stability and electroluminescence (EL) properties due to severe nonradiative recombination induced by large numbers of dangling bond defects and charge imbalance in QD. Herein, dipolar aromatic amine-functionalized molecules with different molecular polarities are employed to regulate charge transport and passivate interfacial defects between QD and the electron transfer layer (ETL). The results show that the stronger the molecular polarity, especially with the -CF3 groups possessing a strong electron-withdrawing capacity, the more effective the defect passivation of S and Zn dangling bonds at the QD surface. Moreover, the dipole interlayer can effectively reduce electron injection into QD at high current density, enhancing charge balance and mitigating Joule heat. Finally, blue QLEDs exhibit a peak external quantum efficiency (EQE) of 21.02% with an operational lifetime (T50 at 100 cd m-2) exceeding 4000 h.
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Affiliation(s)
- Fensha Cai
- Key Lab for Special Functional Materials of Ministry of Education, National & Local Joint Engineering Research Center for High-Efficiency Display and Lighting Technology, School of Materials Science and Engineering, and Collaborative Innovation Center of Nano Functional Materials and Applications, Henan University, Kaifeng 475004, China
| | - Meng Li
- Key Lab for Special Functional Materials of Ministry of Education, National & Local Joint Engineering Research Center for High-Efficiency Display and Lighting Technology, School of Materials Science and Engineering, and Collaborative Innovation Center of Nano Functional Materials and Applications, Henan University, Kaifeng 475004, China
| | - Han Zhang
- Key Lab for Special Functional Materials of Ministry of Education, National & Local Joint Engineering Research Center for High-Efficiency Display and Lighting Technology, School of Materials Science and Engineering, and Collaborative Innovation Center of Nano Functional Materials and Applications, Henan University, Kaifeng 475004, China
| | - Yunqi Wang
- Key Lab for Special Functional Materials of Ministry of Education, National & Local Joint Engineering Research Center for High-Efficiency Display and Lighting Technology, School of Materials Science and Engineering, and Collaborative Innovation Center of Nano Functional Materials and Applications, Henan University, Kaifeng 475004, China
| | - Zhe Li
- School of Engineering and Materials Science (SEMS), Queen Mary University of London, London E1 4NS United Kingdom
| | - Yufei Tu
- School of Electronics Information and Intelligent Manufacturing, Sias University, Xinzheng 451150, China
| | - Mahmoud H Aldamasy
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| | - Xiaohong Jiang
- Key Lab for Special Functional Materials of Ministry of Education, National & Local Joint Engineering Research Center for High-Efficiency Display and Lighting Technology, School of Materials Science and Engineering, and Collaborative Innovation Center of Nano Functional Materials and Applications, Henan University, Kaifeng 475004, China
| | - Bo Hou
- School of Physics and Astronomy, Cardiff University, Cardiff, Wales CF24 3AA, United Kingdom
| | - Shujie Wang
- Key Lab for Special Functional Materials of Ministry of Education, National & Local Joint Engineering Research Center for High-Efficiency Display and Lighting Technology, School of Materials Science and Engineering, and Collaborative Innovation Center of Nano Functional Materials and Applications, Henan University, Kaifeng 475004, China
| | - Zuliang Du
- Key Lab for Special Functional Materials of Ministry of Education, National & Local Joint Engineering Research Center for High-Efficiency Display and Lighting Technology, School of Materials Science and Engineering, and Collaborative Innovation Center of Nano Functional Materials and Applications, Henan University, Kaifeng 475004, China
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21
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Chen Z, Li H, Yuan C, Gao P, Su Q, Chen S. Color Revolution: Prospects and Challenges of Quantum-Dot Light-Emitting Diode Display Technologies. SMALL METHODS 2024; 8:e2300359. [PMID: 37357153 DOI: 10.1002/smtd.202300359] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Revised: 05/15/2023] [Indexed: 06/27/2023]
Abstract
Light-emitting diodes (LEDs) based on colloidal quantum-dots (QDs) such as CdSe, InP, and ZnSeTe feature a unique advantage of narrow emission linewidth of ≈20 nm, which can produce highly accurate colors, making them a highly promising technology for the realization of displays with Rec. 2020 color gamut. With the rapid development in the past decades, the performances of red and green QLEDs have been remarkably improved, and their efficiency and lifetime can almost meet industrial requirements. However, the industrialization of QLED displays still faces many challenges; for example, (1) the device mechanisms including the charge injection/transport/leakage, exciton quenching, and device degradation are still unclear, which fundamentally limit QLED performance improvement; (2) the blue performances including the efficiency, chromaticity, and stability are relatively low, which are still far from the requirements of practical applications; (3) the color patterning processes including the ink-jet printing, transfer printing, and photolithography are still immature, which restrict the manufacturing of high resolution full-color QLED displays. Here, the recent advancements attempting to address the above challenges of QLED displays are specifically reviewed. After a brief overview of QLED development history, device structure/principle, and performances, the main focus is to investigate the recent discoveries on device mechanisms with an emphasis on device degradation. Then recent progress is introduced in blue QLEDs and color patterning. Finally, the opportunities, challenges, solutions, and future research directions of QLED displays are summarized.
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Affiliation(s)
- Zinan Chen
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055, P. R. China
| | - Haotao Li
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055, P. R. China
| | - Cuixia Yuan
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055, P. R. China
| | - Peili Gao
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055, P. R. China
| | - Qiang Su
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055, P. R. China
| | - Shuming Chen
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055, P. R. China
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22
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Gao P, Chen Z, Chen S. Electron-Induced Degradation in Blue Quantum-Dot Light-Emitting Diodes. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2309123. [PMID: 38038258 DOI: 10.1002/adma.202309123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 11/15/2023] [Indexed: 12/02/2023]
Abstract
The poor stability of blue quantum-dot (QD) light-emitting diodes (B-QLEDs) hinders their application in displays. To improve the stability of B-QLEDs, the degradation mechanism should be revealed. Here, the degradation mechanism of B-QLEDs is investigated by monitoring the changes occurring in the QDs and the hole transport layers (HTL) during device operation, respectively. It is revealed that the accumulation of electrons within the QDs is responsible for the degradation of the devices. On the one hand, the accumulated electrons induce the detachment of oleic acid ligands, leading to permanent damage to the stability of B-QDs. On the other hand, the accumulated electrons leak into the HTL or recombine at the HTL/QDs interface, leading to the degradation of HTL. The formation of surface defects in B-QDs and the decomposition of HTL contribute to the degradation of B-QLEDs. The results reveal the strong dependence of B-QLEDs stability on the accumulated electrons, the QDs and the HTL, which can help researchers to develop effective design strategies for improving the lifespan of B-QLEDs.
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Affiliation(s)
- Peili Gao
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055, P. R. China
| | - Zinan Chen
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055, P. R. China
| | - Shuming Chen
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055, P. R. China
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23
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Zhang W, Li B, Chang C, Chen F, Zhang Q, Lin Q, Wang L, Yan J, Wang F, Chong Y, Du Z, Fan F, Shen H. Stable and efficient pure blue quantum-dot LEDs enabled by inserting an anti-oxidation layer. Nat Commun 2024; 15:783. [PMID: 38278797 PMCID: PMC10817946 DOI: 10.1038/s41467-024-44894-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 01/09/2024] [Indexed: 01/28/2024] Open
Abstract
The efficiency and stability of red and green quantum-dot light-emitting diodes have already met the requirements for commercialization in displays. However, the poor stability of the blue ones, particularly pure blue color, is hindering the commercialization of full-color quantum-dot light-emitting diode technology. Severe hole accumulation at the blue quantum-dot/hole-transport layer interface makes the hole-transport layer prone to oxidation, limiting the device operational lifetime. Here, we propose inserting an anti-oxidation layer (poly(p-phenylene benzobisoxazole)) between this interface to take in some holes from the hole-transport layer, which mitigates the oxidation-induced device degradation, enabling a T50 (time for the luminance decreasing by 50%) of more than 41,000 h with an initial brightness of 100 cd m-2 in pure blue devices. Meanwhile, the inserted transition layer facilitates hole injection and helps reduce electron leakage, leading to a peak external quantum efficiency of 23%.
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Affiliation(s)
- Wenjing Zhang
- Key Laboratory for Special Functional Materials of Ministry of Education, National & Local Joint Engineering Research Center for High-efficiency Display and Lighting Technology, Henan University, 475004, Kaifeng, China
| | - Bo Li
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, CAS Key Laboratory of Microscale Magnetic Resonance, Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, 230026, Hefei, China
| | - Chun Chang
- Key Laboratory of Nondestructive Testing Ministry of Education, Nanchang Hangkong University, 330063, Nanchang, China
| | - Fei Chen
- Key Laboratory for Special Functional Materials of Ministry of Education, National & Local Joint Engineering Research Center for High-efficiency Display and Lighting Technology, Henan University, 475004, Kaifeng, China.
| | - Qin Zhang
- Key Laboratory of Nondestructive Testing Ministry of Education, Nanchang Hangkong University, 330063, Nanchang, China
| | - Qingli Lin
- Key Laboratory for Special Functional Materials of Ministry of Education, National & Local Joint Engineering Research Center for High-efficiency Display and Lighting Technology, Henan University, 475004, Kaifeng, China
| | - Lei Wang
- Key Laboratory for Special Functional Materials of Ministry of Education, National & Local Joint Engineering Research Center for High-efficiency Display and Lighting Technology, Henan University, 475004, Kaifeng, China
| | - Jinhang Yan
- Key Laboratory for Special Functional Materials of Ministry of Education, National & Local Joint Engineering Research Center for High-efficiency Display and Lighting Technology, Henan University, 475004, Kaifeng, China
| | - Fangfang Wang
- Key Laboratory for Special Functional Materials of Ministry of Education, National & Local Joint Engineering Research Center for High-efficiency Display and Lighting Technology, Henan University, 475004, Kaifeng, China
| | - Yihua Chong
- Key Laboratory for Special Functional Materials of Ministry of Education, National & Local Joint Engineering Research Center for High-efficiency Display and Lighting Technology, Henan University, 475004, Kaifeng, China
| | - Zuliang Du
- Key Laboratory for Special Functional Materials of Ministry of Education, National & Local Joint Engineering Research Center for High-efficiency Display and Lighting Technology, Henan University, 475004, Kaifeng, China
| | - Fengjia Fan
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, CAS Key Laboratory of Microscale Magnetic Resonance, Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, 230026, Hefei, China.
| | - Huaibin Shen
- Key Laboratory for Special Functional Materials of Ministry of Education, National & Local Joint Engineering Research Center for High-efficiency Display and Lighting Technology, Henan University, 475004, Kaifeng, China.
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24
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Azadinia M, Chun P, Lyu Q, Cotella G, Aziz H. Differences in Electron and Hole Injection and Auger Recombination between Red, Green, and Blue CdSe-Based Quantum Dot Light Emitting Devices. ACS NANO 2024; 18:1485-1495. [PMID: 38175971 DOI: 10.1021/acsnano.3c07999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2024]
Abstract
Despite the significant progress that has been made in recent years in improving the performance of quantum dot light-emitting devices (QLEDs), the effect of charge imbalance and excess carriers on excitons in red (R) vs green (G) vs blue (B) QLEDs has not been compared or systematically studied. In this work we study the effect of changing the electron (e)/hole (h) supply ratio in the QDs emissive layer (EML) in CdSe-based R-, G-, and B-QLEDs with inverted structure in order to identify the type of excess carriers and investigate their effect on the electroluminescence performance of QLEDs of each color. Results show that in R-QLEDs, the e/h ratio in the EML is >1, whereas in G- and B-QLEDs, the e/h ratio is <1 with charge balance conditions being significantly worse in the case of B-QLEDs. Transient photoluminescence (PL) and steady state PL measurements show that, compared to electrons, holes lead to a stronger Auger quenching effect. Transient electroluminescence (TrEL) results indicate that Auger quenching leads to a gradual decline in the EL performance of the QLEDs after a few microseconds, with a stronger effect observed for positive charging versus negative charging. The results provide insights into the differences in the efficiency behavior of R-, G-, and B-QLEDs and uncover the role of excess holes and poor charge balance in the lower efficiency and EL stability of B-QLEDs.
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Affiliation(s)
- Mohsen Azadinia
- Department of Electrical and Computer Engineering and Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
| | - Peter Chun
- Ottawa IC Laboratory, Huawei Canada, 19 Allstate Parkway, Markham, Ontario L3R 5B4, Canada
| | - Quan Lyu
- Ipswich Research Centre, Huawei Technologies Research & Development (U.K.) Ltd., Phoenix House (B55), Adastral Park, Ipswich, IP5 3RE, U.K
| | - Giovanni Cotella
- Ipswich Research Centre, Huawei Technologies Research & Development (U.K.) Ltd., Phoenix House (B55), Adastral Park, Ipswich, IP5 3RE, U.K
| | - Hany Aziz
- Department of Electrical and Computer Engineering and Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
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25
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Ghorbani A, Chen J, Chun P, Lyu Q, Cotella G, Aziz H. Changes in Hole and Electron Injection under Electrical Stress and the Rapid Electroluminescence Loss in Blue Quantum-Dot Light-Emitting Devices. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2304580. [PMID: 37653596 DOI: 10.1002/smll.202304580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 08/17/2023] [Indexed: 09/02/2023]
Abstract
Blue quantum dot light-emitting devices (QLEDs) suffer from fast electroluminescence (EL) loss when under electrical bias. Here, it is identified that the fast EL loss in blue QLEDs is not due to a deterioration in the photoluminescence quantum yield of the quantum dots (QDs), contrary to what is commonly believed, but rather arises primarily from changes in charge injection overtime under the bias that leads to a deterioration in charge balance. Measurements on hole-only and electron-only devices show that hole injection into blue QDs increases over time whereas electron injection decreases. Results also show that the changes are associated with changes in hole and electron trap densities. The results are further verified using QLEDs with blue and red QDs combinations, capacitance versus voltage, and versus time characteristics of the blue QLEDs. The changes in charge injection are also observed to be partially reversible, and therefore using pulsed current instead of constant current bias for driving the blue QLEDs leads to an almost 2.5× longer lifetime at the same initial luminance. This work systematically investigates the origin of blue QLEDs EL loss and provides insights for designing improved blue QDs paving the way for QLEDs technology commercialization.
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Affiliation(s)
- Atefeh Ghorbani
- Department of Electrical and Computer Engineering and Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada
| | - Junfei Chen
- Department of Electrical and Computer Engineering and Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada
- Institute of Optoelectronics Technology, Beijing Jiaotong University, Beijing, 100044, China
| | - Peter Chun
- Ottawa IC Laboratory, Huawei Canada, 19 Allstate Parkway, Markham, Ontario, L3R 5B4, Canada
| | - Quan Lyu
- Ipswich Research Centre, Huawei Technologies Research & Development (UK) Ltd., Phoenix House (B55), Adastral Park, Ipswich, IP5 3RE, UK
| | - Giovanni Cotella
- Ipswich Research Centre, Huawei Technologies Research & Development (UK) Ltd., Phoenix House (B55), Adastral Park, Ipswich, IP5 3RE, UK
| | - Hany Aziz
- Department of Electrical and Computer Engineering and Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada
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26
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He S, Tang X, Deng Y, Yin N, Jin W, Lu X, Chen D, Wang C, Sun T, Chen Q, Jin Y. Anomalous efficiency elevation of quantum-dot light-emitting diodes induced by operational degradation. Nat Commun 2023; 14:7785. [PMID: 38012136 PMCID: PMC10682488 DOI: 10.1038/s41467-023-43340-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Accepted: 11/08/2023] [Indexed: 11/29/2023] Open
Abstract
Quantum-dot light-emitting diodes promise a new generation of high-performance and solution-processed electroluminescent light sources. Understanding the operational degradation mechanisms of quantum-dot light-emitting diodes is crucial for their practical applications. Here, we show that quantum-dot light-emitting diodes may exhibit an anomalous degradation pattern characterized by a continuous increase in electroluminescent efficiency upon electrical stressing, which deviates from the typical decrease in electroluminescent efficiency observed in other light-emitting diodes. Various in-situ/operando characterizations were performed to investigate the evolutions of charge dynamics during the efficiency elevation, and the alterations in electric potential landscapes in the active devices. Furthermore, we carried out selective peel-off-and-rebuild experiments and depth-profiling analyses to pinpoint the critical degradation site and reveal the underlying microscopic mechanism. The results indicate that the operation-induced efficiency increase results from the degradation of electron-injection capability at the electron-transport layer/cathode interface, which in turn leads to gradually improved charge balance. Our work provides new insights into the degradation of red quantum-dot light-emitting diodes and has far-reaching implications for the design of charge-injection interfaces in solution-processed light-emitting diodes.
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Affiliation(s)
- Siyu He
- Key Laboratory of Excited-State Materials of Zhejiang Province, State Key Laboratory of Silicon Materials, Department of Chemistry, Zhejiang University, Hangzhou, China
| | - Xiaoqi Tang
- Key Laboratory of Excited-State Materials of Zhejiang Province, State Key Laboratory of Silicon Materials, Department of Chemistry, Zhejiang University, Hangzhou, China
| | - Yunzhou Deng
- State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, International Research Center for Advanced Photonics, Zhejiang University, Hangzhou, China.
- Cavendish Laboratory, University of Cambridge, Cambridge, UK.
| | - Ni Yin
- i-Lab, CAS Key Laboratory of Nanophotonic Materials and Devices, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, China
| | - Wangxiao Jin
- Key Laboratory of Excited-State Materials of Zhejiang Province, State Key Laboratory of Silicon Materials, Department of Chemistry, Zhejiang University, Hangzhou, China
| | - Xiuyuan Lu
- Key Laboratory of Excited-State Materials of Zhejiang Province, State Key Laboratory of Silicon Materials, Department of Chemistry, Zhejiang University, Hangzhou, China
| | - Desui Chen
- Key Laboratory of Excited-State Materials of Zhejiang Province, State Key Laboratory of Silicon Materials, Department of Chemistry, Zhejiang University, Hangzhou, China
| | - Chenyang Wang
- Key Laboratory of Excited-State Materials of Zhejiang Province, State Key Laboratory of Silicon Materials, Department of Chemistry, Zhejiang University, Hangzhou, China
| | - Tulai Sun
- Center for Electron Microscopy, State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology and College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, China
| | - Qi Chen
- i-Lab, CAS Key Laboratory of Nanophotonic Materials and Devices, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, China.
| | - Yizheng Jin
- Key Laboratory of Excited-State Materials of Zhejiang Province, State Key Laboratory of Silicon Materials, Department of Chemistry, Zhejiang University, Hangzhou, China.
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27
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Yang C, Ma R, Wang Z, Wang Y, Yu C, Liu Y, Wan Y, Li J, Tong J, Zhang P, Zhang H. Efficient Quantum Dot Light-Emitting Diode Enabled by a Thick Inorganic CdS Interfacial Modification Layer. ACS APPLIED MATERIALS & INTERFACES 2023; 15:54185-54191. [PMID: 37943303 DOI: 10.1021/acsami.3c12897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2023]
Abstract
Ultrathin (∼10 nm) insulating polymer films are commonly employed as an interfacial modification layer (IML) to improve charge balance and suppress interfacial exciton quenching in quantum dot light-emitting diodes (QLEDs). However, because the thickness is smaller than the energy transfer distance, interfacial exciton quenching is only partially suppressed, leading to the degrading of device performance. In this work, a thick (35 nm) inorganic CdS film is developed to serve as the IML of CdSe quantum-dot-based QLED. Benefiting from relatively low electron mobility and well-matched energy level, the CdS IML can effectively improve charge balance. In addition, because the thickness is larger than the energy transfer distance, interfacial exciton quenching can be completely blocked. As a result, the QLEDs with CdS IML exhibit a maximum EQE of 21.2% and a peak current efficiency of 24.2 cd A-1, which are about 1.32- and 1.4-fold higher than 16.1% and 17.3 cd A-1 of the devices without CdS IML, respectively. Our work offers an efficient method to completely block interfacial exciton quenching, which may open a new avenue for developing higher-performance QLEDs.
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Affiliation(s)
- Chunyan Yang
- School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou 730000, China
| | - Rui Ma
- School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou 730000, China
| | - Zhe Wang
- State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures, Guangxi University, Nanning 530004,China
- School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China
| | - Yuanyuan Wang
- State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures, Guangxi University, Nanning 530004,China
- School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China
| | - Chaoyu Yu
- State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures, Guangxi University, Nanning 530004,China
- School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China
| | - Yonggang Liu
- School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou 730000, China
| | - Yanfu Wan
- School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou 730000, China
| | - Jianfeng Li
- School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou 730000, China
| | - Junfeng Tong
- School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou 730000, China
| | - Peng Zhang
- School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou 730000, China
| | - Heng Zhang
- State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures, Guangxi University, Nanning 530004,China
- School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China
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28
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Bi Y, Cao S, Yu P, Du Z, Wang Y, Zheng J, Zou B, Zhao J. Reducing Emission Linewidth of Pure-Blue ZnSeTe Quantum Dots through Shell Engineering toward High Color Purity Light-Emitting Diodes. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2303247. [PMID: 37420332 DOI: 10.1002/smll.202303247] [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: 04/17/2023] [Revised: 06/19/2023] [Indexed: 07/09/2023]
Abstract
High color purity blue quantum dot light-emitting diodes (QLEDs) have great potential applications in the field of ultra-high-definition display. However, the realization of eco-friendly pure-blue QLEDs with a narrow emission linewidth for high color purity remains a significant challenge. Herein, a strategy for fabricating high color purity and efficient pure-blue QLEDs based on ZnSeTe/ZnSe/ZnS quantum dots (QDs) is presented. It is found that by finely controlling the internal ZnSe shell thickness of the QDs, the emission linewidth can be narrowed by reducing the exciton-longitudinal optical phonon coupling and trap states in the QDs. Additionally, the regulation of the QD shell thickness can suppress the Förster energy transfer between QDs in the QLED emission layer, which will help to reduce the emission linewidth of the device. As a result, the fabricated pure-blue (452 nm) ZnSeTe QLED with ultra-narrow electroluminescence linewidth (22 nm) exhibit high color purity with the Commission Internationale de l'Eclairage chromatic coordinates of (0.148, 0.042) and considerable external quantum efficiency (18%). This work provides a demonstration of the preparation of pure-blue eco-friendly QLEDs with both high color purity and efficiency, and it is believed that it will accelerate the application process of eco-friendly QLEDs in ultra-high-definition displays.
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Affiliation(s)
- Yuhe Bi
- School of Physical Science and Technology, State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures, Guangxi University, Nanning, 530004, China
| | - Sheng Cao
- School of Physical Science and Technology, State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures, Guangxi University, Nanning, 530004, China
| | - Peng Yu
- School of Physical Science and Technology, State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures, Guangxi University, Nanning, 530004, China
| | - Zhentao Du
- School of Physical Science and Technology, State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures, Guangxi University, Nanning, 530004, China
| | - Yunjun Wang
- Suzhou Xingshuo Nanotech Co., Ltd. (Mesolight), Suzhou, 215123, China
| | - Jinju Zheng
- Institute of Micro/Nano Materials and Devices, Ningbo University of Technology, Ningbo, 315211, China
| | - Bingsuo Zou
- School of Physical Science and Technology, State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures, Guangxi University, Nanning, 530004, China
| | - Jialong Zhao
- School of Physical Science and Technology, State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures, Guangxi University, Nanning, 530004, China
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Saleem MI, Chandrasekar P, Batool A, Lee JH. Aqueous-Phase Formation of Two-Dimensional PbI 2 Nanoplates for High-Performance Self-Powered Photodetectors. MICROMACHINES 2023; 14:1949. [PMID: 37893386 PMCID: PMC10608996 DOI: 10.3390/mi14101949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 10/14/2023] [Accepted: 10/16/2023] [Indexed: 10/29/2023]
Abstract
The process of the aqueous synthesis of nanomaterials has gained considerable interest due to its ability to eliminate the need for complex organic solvents, which aligns with the principles of green chemistry. Fabricating nanostructures in aqueous solutions has gained recognition for its potential to develop ultrasensitive, low-energy, and ultrafast optoelectronic devices. This study focuses on synthesizing lead iodide (PbI2) nanoplates (NPs) using a water-based solution technique and fabricating a planar photodetector. The planar photodetectors (ITO/PbI2 NPs/Au) demonstrated a remarkable photosensitivity of 3.9 × 103 and photoresponsivity of 0.51 mA/W at a wavelength of 405 nm. Further, we have carried-out analytical calculations for key performance parameters including open-circuit voltage (Voc), short-circuit current (Isc), on-off ratio, responsivity (R), and specific detectivity (D*) at zero applied bias, while photodetector operating in self-powered mode. These values are as follows: Voc = 0.103 V, Isc = 1.93 × 10-8, on-off ratio = 103, R = 4.0 mA/W, and D* = 3.3 × 1011 Jones. Particularly, the asymmetrical output properties of ITO/PbI2 NPs/Au detector provided additional evidence of the effective creation of a Schottky contact. Therefore, the photodetector exhibited a photo-response even at 0 V bias (rise/decay time ~1 s), leading to the realization of self-powered photodetectors. Additionally, the device exhibited a rapid photo-response of 0.23/0.38 s (-5 V) in the visible range. This study expands the scope of aqueous-phase synthesis of PbI2 nanostructures, enabling the large-area fabrication of high-performance photodetectors.
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Affiliation(s)
- Muhammad Imran Saleem
- Department of Materials Science and Engineering, Inha University, Incheon 22212, Republic of Korea;
| | | | - Attia Batool
- Research Center for Materials Science, Beijing Institute of Technology, Beijing 100081, China;
| | - Jeong-Hwan Lee
- Department of Materials Science and Engineering, Inha University, Incheon 22212, Republic of Korea;
- 3D Convergence Center, Inha University, Incheon 22212, Republic of Korea
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30
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Zhang X, Bao H, Chen C, Wu XG, Li M, Ji W, Wang S, Zhong H. The fatigue effects in red emissive CdSe based QLED operated around turn-on voltage. J Chem Phys 2023; 158:131101. [PMID: 37031138 DOI: 10.1063/5.0145471] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023] Open
Abstract
The operational stability is a current bottleneck facing the quantum dot light-emitting diodes (QLEDs). In particular, the device working around turn-on voltage suffers from unbalanced charge injection and heavy power loss. Here, we investigate the operational stability of red emissive CdSe QLEDs operated at different applied voltages. Compared to the rising luminance at higher voltages, the device luminance quickly decreases when loaded around the turn-on voltage, but recovers after unloading or slight heat treatment, which is termed fatigue effects of operational QLED. The electroluminescence and photoluminescence spectra before and after a period of operation at low voltages show that the abrupt decrease in device luminance derives from the reduction of quantum yield in quantum dots. Combined with transient photoluminescence and electroluminescence measurements, as well as equivalent circuit model analysis, the electron accumulation in quantum dots mainly accounts for the observed fatigue effects of a QLED during the operation around turn-on voltage. The underlying mechanisms at the low-voltage working regime will be very helpful for the industrialization of QLED.
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Affiliation(s)
- Xin Zhang
- MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Hui Bao
- MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Cuili Chen
- MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Xian-gang Wu
- MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Menglin Li
- MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Wenyu Ji
- Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University, Changchun 130012, China
| | - Shuangpeng Wang
- Institute of Applied Physics and Materials Engineering, University of Macau, Taipa, Macao SAR, 999078, China
| | - Haizheng Zhong
- MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China
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Bao H, Chen C, Cao Y, Chang S, Wang S, Zhong H. Quantitative Determination of Charge Accumulation and Recombination in Operational Quantum Dots Light Emitting Diodes via Time-Resolved Electroluminescence Spectroscopy. J Phys Chem Lett 2023; 14:1777-1783. [PMID: 36762889 DOI: 10.1021/acs.jpclett.3c00070] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
In this work, we report the quantitative determination of charge accumulation and recombination in an operated QLED using time-resolved electroluminescence (TREL) spectroscopy. As a supplement technique, time-resolved current (TRC) measurement was introduced and simulated using equivalent circuit model with a series resistance, a parallel resistance, and a capacitance. By modeling the key processes in a typical TREL spectra, the stages of delay, rising, and decay can be correlated to the charge accumulations, charge injection and recombination, and charge release and recombination, respectively. In particular, the rising stage can be described using a modified Langevin recombination model. The electroluminescence recombination rate can be derived by fitting the rising stage curves in the TREL spectra, providing an intrinsic parameter of the emissive materials. In all, this work provides a methodology to quantitatively determine the charge accumulation and recombination of an operational QLED device.
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Affiliation(s)
- Hui Bao
- MIIT Key Laboratory for Low Dimensional Quantum Structure and Devices, School of Materials Sciences & Engineering, Beijing Institute of Technology, 100081 Beijing, China
| | - Cuili Chen
- MIIT Key Laboratory for Low Dimensional Quantum Structure and Devices, School of Photonics and Optics, Beijing Institute of Technology, 100081 Beijing, China
| | - Yongqi Cao
- MIIT Key Laboratory for Low Dimensional Quantum Structure and Devices, School of Materials Sciences & Engineering, Beijing Institute of Technology, 100081 Beijing, China
| | - Shuai Chang
- Department of Materials Science, Shenzhen MSU-BIT University, 518172 Shenzhen, China
| | - Shuangpeng Wang
- Institute of Applied Physics and Materials Engineering, University of Macau, 999078 Macau, China
| | - Haizheng Zhong
- MIIT Key Laboratory for Low Dimensional Quantum Structure and Devices, School of Materials Sciences & Engineering, Beijing Institute of Technology, 100081 Beijing, China
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