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Xiao P, Yu Y, Cheng J, Chen Y, Yuan S, Chen J, Yuan J, Liu B. Advances in Perovskite Light-Emitting Diodes Possessing Improved Lifetime. NANOMATERIALS (BASEL, SWITZERLAND) 2021; 11:E103. [PMID: 33406749 PMCID: PMC7823701 DOI: 10.3390/nano11010103] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 12/23/2020] [Accepted: 12/26/2020] [Indexed: 12/14/2022]
Abstract
Recently, perovskite light-emitting diodes (PeLEDs) are seeing an increasing academic and industrial interest with a potential for a broad range of technologies including display, lighting, and signaling. The maximum external quantum efficiency of PeLEDs can overtake 20% nowadays, however, the lifetime of PeLEDs is still far from the demand of practical applications. In this review, state-of-the-art concepts to improve the lifetime of PeLEDs are comprehensively summarized from the perspective of the design of perovskite emitting materials, the innovation of device engineering, the manipulation of optical effects, and the introduction of advanced encapsulations. First, the fundamental concepts determining the lifetime of PeLEDs are presented. Then, the strategies to improve the lifetime of both organic-inorganic hybrid and all-inorganic PeLEDs are highlighted. Particularly, the approaches to manage optical effects and encapsulations for the improved lifetime, which are negligibly studied in PeLEDs, are discussed based on the related concepts of organic LEDs and Cd-based quantum-dot LEDs, which is beneficial to insightfully understand the lifetime of PeLEDs. At last, the challenges and opportunities to further enhance the lifetime of PeLEDs are introduced.
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Affiliation(s)
- Peng Xiao
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, Foshan University, Foshan 528225, China; (P.X.); (J.C.); (Y.C.); (S.Y.); (J.C.); (J.Y.)
| | - Yicong Yu
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, Foshan University, Foshan 528225, China; (P.X.); (J.C.); (Y.C.); (S.Y.); (J.C.); (J.Y.)
| | - Junyang Cheng
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, Foshan University, Foshan 528225, China; (P.X.); (J.C.); (Y.C.); (S.Y.); (J.C.); (J.Y.)
| | - Yonglong Chen
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, Foshan University, Foshan 528225, China; (P.X.); (J.C.); (Y.C.); (S.Y.); (J.C.); (J.Y.)
| | - Shengjin Yuan
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, Foshan University, Foshan 528225, China; (P.X.); (J.C.); (Y.C.); (S.Y.); (J.C.); (J.Y.)
| | - Jianwen Chen
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, Foshan University, Foshan 528225, China; (P.X.); (J.C.); (Y.C.); (S.Y.); (J.C.); (J.Y.)
| | - Jian Yuan
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, Foshan University, Foshan 528225, China; (P.X.); (J.C.); (Y.C.); (S.Y.); (J.C.); (J.Y.)
| | - Baiquan Liu
- School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510275, China
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Luo D, Wang L, Qiu Y, Huang R, Liu B. Emergence of Impurity-Doped Nanocrystal Light-Emitting Diodes. NANOMATERIALS (BASEL, SWITZERLAND) 2020; 10:E1226. [PMID: 32599722 PMCID: PMC7353084 DOI: 10.3390/nano10061226] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 06/17/2020] [Accepted: 06/17/2020] [Indexed: 11/16/2022]
Abstract
In recent years, impurity-doped nanocrystal light-emitting diodes (LEDs) have aroused both academic and industrial interest since they are highly promising to satisfy the increasing demand of display, lighting, and signaling technologies. Compared with undoped counterparts, impurity-doped nanocrystal LEDs have been demonstrated to possess many extraordinary characteristics including enhanced efficiency, increased luminance, reduced voltage, and prolonged stability. In this review, recent state-of-the-art concepts to achieve high-performance impurity-doped nanocrystal LEDs are summarized. Firstly, the fundamental concepts of impurity-doped nanocrystal LEDs are presented. Then, the strategies to enhance the performance of impurity-doped nanocrystal LEDs via both material design and device engineering are introduced. In particular, the emergence of three types of impurity-doped nanocrystal LEDs is comprehensively highlighted, namely impurity-doped colloidal quantum dot LEDs, impurity-doped perovskite LEDs, and impurity-doped colloidal quantum well LEDs. At last, the challenges and the opportunities to further improve the performance of impurity-doped nanocrystal LEDs are described.
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Affiliation(s)
- Dongxiang Luo
- Institute of Semiconductors, South China Normal University, Guangzhou 510631, China;
| | - Lin Wang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore;
| | - Ying Qiu
- Guangdong R&D Center for Technological Economy, Guangzhou 510000, China
| | - Runda Huang
- School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, China;
| | - Baiquan Liu
- State Key Laboratory of Optoelectronic Materials and Technologies and the Guangdong Province Key Laboratory of Display Material and Technology, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510275, China
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Luo D, Chen Q, Qiu Y, Zhang M, Liu B. Device Engineering for All-Inorganic Perovskite Light-Emitting Diodes. NANOMATERIALS (BASEL, SWITZERLAND) 2019; 9:E1007. [PMID: 31336905 PMCID: PMC6669542 DOI: 10.3390/nano9071007] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 07/04/2019] [Accepted: 07/10/2019] [Indexed: 01/12/2023]
Abstract
Recently, all-inorganic perovskite light-emitting diodes (PeLEDs) have attracted both academic and industrial interest thanks to their outstanding properties, such as high efficiency, bright luminance, excellent color purity, low cost and potentially good operational stability. Apart from the design and treatment of all-inorganic emitters, the device engineering is another significant factor to guarantee the high performance. In this review, we have summarized the state-of-the-art concepts for device engineering in all-inorganic PeLEDs, where the charge injection, transport, balance and leakage play a critical role in the performance. First, we have described the fundamental concepts of all-inorganic PeLEDs. Then, we have introduced the enhancement of device engineering in all-inorganic PeLEDs. Particularly, we have comprehensively highlighted the emergence of all-inorganic PeLEDs, strategies to improve the hole injection, approaches to enhance the electron injection, schemes to increase the charge balance and methods to decrease the charge leakage. Finally, we have clarified the issues and ways to further enhance the performance of all-inorganic PeLEDs.
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Affiliation(s)
- Dongxiang Luo
- School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, China
| | - Qizan Chen
- School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, China
| | - Ying Qiu
- Guangdong R&D Center for Technological Economy, Guangzhou 510000, China.
| | - Menglong Zhang
- School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, China
- Institute of Semiconductors, South China Normal University, Guangzhou 510000, China
| | - Baiquan Liu
- State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China.
- LUMINOUS! Centre of Excellent for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798, Singapore.
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Luo D, Chen Q, Liu B, Qiu Y. Emergence of Flexible White Organic Light-Emitting Diodes. Polymers (Basel) 2019; 11:E384. [PMID: 30960368 PMCID: PMC6419156 DOI: 10.3390/polym11020384] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 02/19/2019] [Accepted: 02/21/2019] [Indexed: 11/17/2022] Open
Abstract
Flexible white organic light-emitting diodes (FWOLEDs) have considerable potential to meet the rapidly growing requirements of display and lighting commercialization. To achieve high-performance FWOLEDs, (i) the selection of effective flexible substrates, (ii) the use of transparent conducting electrodes, (iii) the introduction of efficient device architectures, and iv) the exploitation of advanced outcoupling techniques are necessary. In this review, recent state-of-the-art strategies to develop FWOLEDs have been summarized. Firstly, the fundamental concepts of FWOLEDs have been described. Then, the primary approaches to realize FWOLEDs have been introduced. Particularly, the effects of flexible substrates, conducting electrodes, device architectures, and outcoupling techniques in FWOLEDs have been comprehensively highlighted. Finally, issues and ways to further enhance the performance of FWOLEDs have been briefly clarified.
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Affiliation(s)
- Dongxiang Luo
- School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, China.
| | - Qizan Chen
- School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, China.
| | - Baiquan Liu
- LUMINOUS! Centre of Excellent for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798, Singapore.
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China.
| | - Ying Qiu
- Guangdong R&D Center for Technological Economy, Guangzhou 510000, China.
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Xiao P, Huang J, Yu Y, Liu B. Recent Developments in Tandem White Organic Light-Emitting Diodes. Molecules 2019; 24:E151. [PMID: 30609748 PMCID: PMC6337303 DOI: 10.3390/molecules24010151] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 12/24/2018] [Accepted: 12/25/2018] [Indexed: 12/20/2022] Open
Abstract
Tandem white organic light-emitting diodes (WOLEDs) are promising for the lighting and displays field since their current efficiency, external quantum efficiency and lifetime can be strikingly enhanced compared with single-unit devices. In this invited review, we have firstly described fundamental concepts of tandem device architectures and their use in WOLEDs. Then, we have summarized the state-of-the-art strategies to achieve high-performance tandem WOLEDs in recent years. Specifically, we have highlighted the developments in the four types of tandem WOLEDs (i.e., tandem fluorescent WOLEDs, tandem phosphorescent WOLEDs, tandem thermally activated delayed fluorescent WOLEDs, and tandem hybrid WOLEDs). Furthermore, we have introduced doping-free tandem WOLEDs. In the end, we have given an outlook for the future development of tandem WOLEDs.
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Affiliation(s)
- Peng Xiao
- School of Physics and Optoelectronic Engineering, Foshan University, Foshan 528000, China.
| | - Junhua Huang
- School of Physics and Optoelectronic Engineering, Foshan University, Foshan 528000, China.
| | - Yicong Yu
- School of Physics and Optoelectronic Engineering, Foshan University, Foshan 528000, China.
| | - Baiquan Liu
- LUMINOUS! Centre of Excellent for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798, Singapore.
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China.
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Luo D, Xiao P, Liu B. Doping-Free White Organic Light-Emitting Diodes. CHEM REC 2018; 19:1596-1610. [PMID: 30548958 DOI: 10.1002/tcr.201800147] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 11/28/2018] [Indexed: 11/11/2022]
Abstract
Doping-free white organic light-emitting diodes (WOLEDs) have great potential to the next-generation solid-state lighting and displays due to the excellent properties, such as high efficiency, bright luminance, low power consumption, simplified structure and low cost. In this account, our recent developments on doping-free WOLEDs have been summarized. Firstly, fundamental concepts of doping-free WOLEDs have been described. Then, the effective strategies to develop doping-free WOLEDs have been presented. Particularly, the manipulation of charges and excitons distribution in different kinds of doping-free WOLEDs have been highlighted, including doping-free fluorescent/phosphorescent hybrid WOLEDs, doping-free thermally activated delayed fluorescent WOLEDs and doping-free phosphorescent WOLEDs. In the end, an outlook for the future development of doping-free WOLEDs have been clarified.
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Affiliation(s)
- Dongxiang Luo
- School of Materials and Energy, Guangdong University of Technology, Guangzhou, 510006, China
| | - Peng Xiao
- School of Physics and Optoelectronic Engineering, Foshan University, Foshan, 528000, China
| | - Baiquan Liu
- LUMINOUS!, Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, Nanyang Technological University, Nanyang Avenue, 639798, Singapore.,Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, China
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Recent Advances of Exciplex-Based White Organic Light-Emitting Diodes. APPLIED SCIENCES-BASEL 2018. [DOI: 10.3390/app8091449] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Recently, exciplexes have been actively investigated in white organic light-emitting diodes (WOLEDs), since they can be effectively functioned as (i) fluorescent or thermally activated delayed fluorescent (TADF) emitters; (ii) the hosts of fluorescent, phosphorescent and TADF dopants. By virtue of the unique advantages of exciplexes, high-performance exciplex-based WOLEDs can be achieved. In this invited review, we have firstly described fundamental concepts of exciplexes and their use in organic light-emitting diodes (OLEDs). Then, we have concluded the primary strategies to develop exciplex-based WOLEDs. Specifically, we have emphasized the representative WOLEDs using exciplex emitters or hosts. In the end, we have given an outlook for the future development of exciplex-based WOLEDs.
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Electrical Conductivity and Optical Properties of Pulsed Laser Deposited LaNi₅ Nanoscale Films. MATERIALS 2018; 11:ma11081475. [PMID: 30126256 PMCID: PMC6120037 DOI: 10.3390/ma11081475] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 08/14/2018] [Accepted: 08/17/2018] [Indexed: 02/07/2023]
Abstract
This work presents pulsed laser deposition as a method to obtain unoxidized LaNi₅ nanoscale films and describes their temperature and thickness dependent electrical conductivity and the spectral dispersions of some optical properties. AB₅-type rare earth element (REE)-nickel compounds are currently studied from both theoretical and practical points of view. Special challenges are posed during the preparation of these nanomaterials, which can be overcome using finely tuned parameters in a preparation process that always involves the use of high energies. Film deposition was made by laser-induced vaporization, with short and modulated impulses and electro⁻optical tuning of the quality factor, mainly on glass and one SiO₂ substrate. Deposition geometry dependent linear thickness increase, between 1.5⁻2.5 nm per laser burst, was achieved. Film structures and phase compositions were determined using XRD and discussed in comparison with films obtained by similar deposition procedures. Temperature and scale dependent properties were determined by studying electrical conductivity and optical properties. Electrical conductivity was measured using the four-probe method. The observed semiconductor-like conductivity for film thicknesses up to 110 nm can be explained by thermal activation of electrons followed by inter-insular hopping or quantum tunneling, which, on the other hand, modulates the material's native metallic conductance. Films with thicknesses above this value can be considered essentially metallic and bulk-like. The spectral behaviors of the refractive index and absorption coefficient were deduced from differential reflectance spectroscopy data acquired on a broad ultraviolet, visible, near- and mid-infrared (UV-VIS-NIR-MIR) domain, processed using the Kramers-Krönig formalism. Their study led to the identification of the allowed interband transitions. Electronic behavior in the energy bands near the Fermi level and in the surface and interface-states was described, discussing the differences between experimental data and the classical free-electron theoretical model applied for the bulk intermetallic alloy, in correlation with theoretical optical properties or experimental X-ray photoelectron spectroscopy (XPS) results from references. However, the dielectric-like shape of the reflectance of the thinnest film was in accordance with the Lorentz⁻Drude model.
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