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Chen ZY, Zhang RJ, Wang YP, Yin D, Liu YF, Bi YG, Feng J. Efficient and stretchable organic light-emitting devices based on spontaneously formed disordered wrinkles. OPTICS LETTERS 2022; 47:3744-3747. [PMID: 35913304 DOI: 10.1364/ol.462931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 07/04/2022] [Indexed: 06/15/2023]
Abstract
We propose a facile, scalable strategy to introduce spontaneously formed disordered wrinkles into organic light-emitting devices (OLEDs) to enhance light extraction and realize stretchability of the devices. The luminance and current efficiency of the wrinkled OLEDs are improved by 37% and 18%, respectively, compared to the planar device. Meanwhile, broadband light scattering induced by the disordered wrinkles results in angle-stable electroluminescent spectra at wide viewing angles for the wrinkled OLEDs. The disordered wrinkles enable the OLEDs to be stretchable and withstand hundreds of stretching-releasing cycles at strain between 0% and 5%. This study provides a simple method to realize stretchable OLEDs with high efficiency.
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Choi GS, Kang SW, Bae EJ, Jang EB, Baek DH, Ju BK, Park YW. A Simple Method for Fabricating an External Light Extraction Composite Layer with RNS to Improve the Optical Properties of OLEDs. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:1430. [PMID: 35564139 PMCID: PMC9103064 DOI: 10.3390/nano12091430] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 03/29/2022] [Accepted: 04/20/2022] [Indexed: 02/01/2023]
Abstract
In this study, we fabricated a random nanostructure (RNS) external light extraction composite layer containing high-refractive-index nanoparticles through a simple and inexpensive solution process and a low-temperature mask-free process. We focused on varying the shape and density of the RNSs and adjusted the concentration of the high-refractive-index nanoparticles to control the optical properties. The RNSs fabricated using a low-temperature mask-free process can use the distance between the nanostructures and various forms to control the diffraction and scattering effects in the visible light wavelength range. Consequently, our film exhibited a direct transmittance of ~85% at a wavelength of 550 nm. Furthermore, when the RNSs' composite film, manufactured using the low-temperature mask-free process, was applied to organic light-emitting diodes (OLEDs), it exhibited an external quantum efficiency improvement of 32.2% compared with the OLEDs without the RNSs. Therefore, the randomly distributed high-refractive-index nanoparticles on the polymer film can reduce the waveguide mode and total reflection at the substrate/air interface. These films can be used as a scattering layer to reduce the loss of the OLED substrate mode.
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Affiliation(s)
- Geun-Su Choi
- Nano and Organic-Electronics Laboratory, Department of Display and Semiconductor Engineering, Sun Moon University, Asan 31460, Korea; (G.-S.C.); (S.-W.K.); (E.-J.B.); (E.-B.J.)
| | - Shin-Woo Kang
- Nano and Organic-Electronics Laboratory, Department of Display and Semiconductor Engineering, Sun Moon University, Asan 31460, Korea; (G.-S.C.); (S.-W.K.); (E.-J.B.); (E.-B.J.)
- Display and Nanosystem Laboratory, Department of Electrical Engineering, Korea University, Seoul 02841, Korea
| | - Eun-Jeong Bae
- Nano and Organic-Electronics Laboratory, Department of Display and Semiconductor Engineering, Sun Moon University, Asan 31460, Korea; (G.-S.C.); (S.-W.K.); (E.-J.B.); (E.-B.J.)
- Display and Nanosystem Laboratory, Department of Electrical Engineering, Korea University, Seoul 02841, Korea
| | - Eun-Bi Jang
- Nano and Organic-Electronics Laboratory, Department of Display and Semiconductor Engineering, Sun Moon University, Asan 31460, Korea; (G.-S.C.); (S.-W.K.); (E.-J.B.); (E.-B.J.)
| | - Dong-Hyun Baek
- Center for Next Generation Semiconductor Technology, Department of Display and Semiconductor Engineering, Sun Moon University, Asan 31460, Korea;
| | - Byeong-Kwon Ju
- Display and Nanosystem Laboratory, Department of Electrical Engineering, Korea University, Seoul 02841, Korea
| | - Young-Wook Park
- Nano and Organic-Electronics Laboratory, Department of Display and Semiconductor Engineering, Sun Moon University, Asan 31460, Korea; (G.-S.C.); (S.-W.K.); (E.-J.B.); (E.-B.J.)
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Zheng M, Fang G. Luminescence enhancement of lead halide perovskite light-emitting diodes with plasmonic metal nanostructures. NANOSCALE 2021; 13:16427-16447. [PMID: 34590647 DOI: 10.1039/d1nr05667k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Metal halide perovskites, as newly emerging light emitters, have been attracting considerable attention on luminescent materials and devices, due to their superior optoelectronic properties and potential practical applications. Recently, perovskite light-emitting diodes (PeLEDs) based on lead halide perovskites (LHPs) have been largely designed and intensively studied in laboratory platforms. However, to satisfy demand and promote their commercialization, it is crucial to improve the efficiency and stability of PeLEDs. Accordingly, the surface-plasmon (SP) effect provides a promising approach to enhance their luminescence, which is realized by incorporating plasmonic metal nanostructures (NSs) into PeLEDs. This review presents a comprehensive overview of the research status and prospect on LHP-based plasmonic PeLEDs together with the corresponding perovskite light-emission films (PeLEFs). Firstly, the recent development of the PeLEDs is briefly introduced. Secondly, the mechanisms and photophysics of the PeLEDs by SP manipulation are simply illustrated and analyzed. Then, the recent progress and achievements on the theoretical and experimental results of SP effect applications in the PeLEDs together with PeLEFs are presented in detail and systematically reviewed. Next, the current challenges and future directions of the PeLEDs are shown and discussed. Finally, a critical summary and outlook of the PeLEDs are summarized and proposed. Our results indicate that this new class of LHP-based plasmonic PeLEDs presents future research fields and demonstrates promising applications in lighting and displays, and further luminescence enhancement in exciton radiation processes and light extraction techniques are a hopeful route to obtain high-performance PeLEDs.
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Affiliation(s)
- Mingfei Zheng
- Key Laboratory of Artificial Micro- and Nano-structures of the Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072, P. R. China.
| | - Guojia Fang
- Key Laboratory of Artificial Micro- and Nano-structures of the Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072, P. R. China.
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Nagpal K, Rauwel E, Ducroquet F, Rauwel P. Assessment of the optical and electrical properties of light-emitting diodes containing carbon-based nanostructures and plasmonic nanoparticles: a review. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2021; 12:1078-1092. [PMID: 34631340 PMCID: PMC8474067 DOI: 10.3762/bjnano.12.80] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 09/16/2021] [Indexed: 06/13/2023]
Abstract
Light-emitting diodes (LED) are widely employed in display applications and lighting systems. Further research on LED that incorporates carbon nanostructures and metal nanoparticles exhibiting surface plasmon resonance has demonstrated a significant improvement in device performance. These devices offer lower turn-on voltages, higher external quantum efficiencies, and luminance. De facto, plasmonic nanoparticles, such as Au and Ag have boosted the luminance of red, green, and blue emissions. When combined with carbon nanostructures they additionally offer new possibilities towards lightweight and flexible devices with better thermal management. This review surveys the diverse possibilities to combine various inorganic, organic, and carbon nanostructures along with plasmonic nanoparticles. Such combinations would allow an enhancement in the overall properties of LED.
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Affiliation(s)
- Keshav Nagpal
- Institute of Technology, Estonian University of Life Sciences, Kreutzwaldi 56/1, 51014 Tartu, Estonia
| | - Erwan Rauwel
- Institute of Technology, Estonian University of Life Sciences, Kreutzwaldi 56/1, 51014 Tartu, Estonia
| | | | - Protima Rauwel
- Institute of Technology, Estonian University of Life Sciences, Kreutzwaldi 56/1, 51014 Tartu, Estonia
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Mao P, Liu C, Li X, Liu M, Chen Q, Han M, Maier SA, Sargent EH, Zhang S. Single-step-fabricated disordered metasurfaces for enhanced light extraction from LEDs. LIGHT, SCIENCE & APPLICATIONS 2021; 10:180. [PMID: 34489399 PMCID: PMC8421350 DOI: 10.1038/s41377-021-00621-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 08/13/2021] [Accepted: 08/19/2021] [Indexed: 05/28/2023]
Abstract
While total internal reflection (TIR) lays the foundation for many important applications, foremost fibre optics that revolutionised information technologies, it is undesirable in some other applications such as light-emitting diodes (LEDs), which are a backbone for energy-efficient light sources. In the case of LEDs, TIR prevents photons from escaping the constituent high-index materials. Advances in material science have led to good efficiencies in generating photons from electron-hole pairs, making light extraction the bottleneck of the overall efficiency of LEDs. In recent years, the extraction efficiency has been improved, using nanostructures at the semiconductor/air interface that outcouple trapped photons to the outside continuum. However, the design of geometrical features for light extraction with sizes comparable to or smaller than the optical wavelength always requires sophisticated and time-consuming fabrication, which causes a gap between lab demonstration and industrial-level applications. Inspired by lightning bugs, we propose and realise a disordered metasurface for light extraction throughout the visible spectrum, achieved with single-step fabrication. By applying such a cost-effective light extraction layer, we improve the external quantum efficiency by a factor of 1.65 for commercialised GaN LEDs, demonstrating a substantial potential for global energy-saving and sustainability.
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Affiliation(s)
- Peng Mao
- School of Physics and Astronomy, University of Birmingham, B15 2TT, Birmingham, UK
- National Laboratory of Solid State Microstructures, College of Engineering and Applied Sciencesand Collaborative Innovation Centre of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Changxu Liu
- School of Physics and Astronomy, University of Birmingham, B15 2TT, Birmingham, UK.
- Chair in Hybrid Nanosystems, Nanoinstitute Munich, Faculty of Physics, Ludwig-Maximilians-Universitaet Muenchen, 80539, Muenchen, Germany.
| | - Xiyan Li
- Department of Electrical and Computer Engineering, University of Toronto, 35 St. George Street, Toronto, ON, M5S 1A4, Canada
| | - Mengxia Liu
- Department of Electrical and Computer Engineering, University of Toronto, 35 St. George Street, Toronto, ON, M5S 1A4, Canada
| | - Qiang Chen
- National Laboratory of Solid State Microstructures, College of Engineering and Applied Sciencesand Collaborative Innovation Centre of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
- Key Laboratory of Intelligent Optical Sensing and Manipulation (Nanjing University), Ministry of Education, Nanjing, China
| | - Min Han
- National Laboratory of Solid State Microstructures, College of Engineering and Applied Sciencesand Collaborative Innovation Centre of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Stefan A Maier
- Chair in Hybrid Nanosystems, Nanoinstitute Munich, Faculty of Physics, Ludwig-Maximilians-Universitaet Muenchen, 80539, Muenchen, Germany
- Department of Physics, Imperial College London, London, SW7 2AZ, UK
| | - Edward H Sargent
- Department of Electrical and Computer Engineering, University of Toronto, 35 St. George Street, Toronto, ON, M5S 1A4, Canada.
| | - Shuang Zhang
- School of Physics and Astronomy, University of Birmingham, B15 2TT, Birmingham, UK.
- Department of Physics, University of Hong Kong, Hong Kong, 999077, China.
- Department of Electrical and Electronic Engineering, University of Hong Kong, Hong Kong, 999077, China.
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Chen G, Weng Y, Lai X, Wang W, Zhou X, Yan Q, Guo T, Zhang Y, Wu C. Design and fabrication of hybrid MLAs/gratings for the enhancement of light extraction efficiency and distribution uniformity of OLEDs. OPTICS EXPRESS 2021; 29:25812-25823. [PMID: 34614901 DOI: 10.1364/oe.427258] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 07/21/2021] [Indexed: 06/13/2023]
Abstract
Extracting light from organic light-emitting diodes (OLEDs) and improving the angular distribution are essential for their commercial applications in illumination and displays. In this work, hybrid microlens arrays (MLAs) and gratings with periods and depths in the scale of submicron have been designed and incorporated on the lighting surface of OLEDs for simultaneous enhancement of light outcoupling efficiency and angular distribution improvement. It is found that the augmentation of light extraction efficiency is mainly attributed to the MLAs, while the gratings can improve the viewing angle by increasing the angular distribution uniformity. A novel approach was proposed by combining photoresist thermal reflow, soft-lithography and plasma treatments on polydimethylsiloxane (PDMS) surfaces synergistically to realize gratings on the wavy surface of MLAs. It has been proved that with the hybrid MLAs/gratings, the external quantum efficiency (EQE) of the OLED can reach up to 22.8%, which increased by 24% compared to that of bare OLED. Moreover, the OLED with the hybrid MLAs/gratings showed an obvious lateral enhancement at wider viewing angle.
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Cheng Z, Javed N, O'Carroll DM. Optical and Electrical Properties of Organic Semiconductor Thin Films on Aperiodic Plasmonic Metasurfaces. ACS APPLIED MATERIALS & INTERFACES 2020; 12:35579-35587. [PMID: 32643375 DOI: 10.1021/acsami.0c07099] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Metal electrodes are playing an increasingly important role in controlling photon absorption and in promoting optimal light management in thin-film semiconductor devices. For organic optoelectronic devices, the conventional fabrication approach is to build the device on top of a transparent electrode, with metal electrode deposition as the last step. This makes it challenging to control the surface of the metal electrode to promote good light management properties. An inverted fabrication approach that builds the device on top of a metal electrode makes it possible to control the morphology of the metal surface independently of the organic semiconductor active layer to achieve a variety of photonic and plasmonic behaviors useful for devices. However, there are few reports of inverted fabrication of organic optoelectronic devices and its impacts on device properties. Silver (Ag) is the most suitable metal for fabrication of nanostructured electrodes with plasmonic behavior (i.e., plasmonic electrodes) because of its low parasitic absorption loss and high reflectivity. In this project, we describe the facile fabrication of silver nanoparticle (AgNP) aperiodic plasmonic metasurfaces and study their physical and optical characteristics. Then, we investigate the photonic and electrical behaviors of the aperiodic plasmonic metasurfaces when interfaced with poly(9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT) organic semiconducting polymer thin films. The luminescence quantum yield of F8BT thin films increases from 29% on planar Ag up to 66% on AgNP metasurfaces due to the Purcell effect and the improved extraction of emission coupled to surface plasmon polariton modes. In particular, we show that plasmonic enhancement can overcome ohmic losses associated with metals and metal-induced exciton quenching. According to the current-voltage characteristics of hole-only devices with and without aperiodic plasmonic metasurfaces, we conclude that AgNP aperiodic plasmonic metasurfaces have comparable electrical behavior to planar metal electrodes while having superior light management capability.
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Affiliation(s)
- Zhongkai Cheng
- Department of Chemistry and Chemical Biology, Rutgers University, 123 Bevier Road, Piscataway, New Jersey 08854, United States
| | - Nasir Javed
- Department of Material Science and Engineering, Rutgers University, 607 Taylor Road, Piscataway, New Jersey 08854, United States
| | - Deirdre M O'Carroll
- Department of Chemistry and Chemical Biology, Rutgers University, 123 Bevier Road, Piscataway, New Jersey 08854, United States
- Department of Material Science and Engineering, Rutgers University, 607 Taylor Road, Piscataway, New Jersey 08854, United States
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Gu L, Wen K, Peng Q, Huang W, Wang J. Surface-Plasmon-Enhanced Perovskite Light-Emitting Diodes. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e2001861. [PMID: 32573954 DOI: 10.1002/smll.202001861] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 04/29/2020] [Indexed: 06/11/2023]
Abstract
Perovskite light-emitting diodes (PeLEDs) have attracted considerable attention because of their potential in display and lighting applications. To promote commercialization of PeLEDs, it is important to improve the external quantum efficiency of the devices, which depends on their internal quantum efficiency (IQE) and light extraction efficiency. Optical simulations have revealed that 20-50% of the light generated in the device will be lost to surface plasmon (SP) modes formed in the metal/dielectric interfaces. Therefore, extracting the optical energy in SP modes to the air will greatly increase the light extraction efficiency of PeLEDs. In addition, the SPs can accelerate radiative recombination of the emitter via near-field effects. Thus, the IQE of a PeLED can also be enhanced by SP manipulation. In this review, first, general concepts of the SPs and how they can enhance the efficiency of LEDs are introduced. Then recent progresses in SP-enhanced emission of perovskite films and LEDs are systematically reviewed. After that, the challenges and opportunities of the SP-enhanced PeLEDs are shown, followed by an outlook of further development of the SPs in perovskite optoelectronic devices.
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Affiliation(s)
- Lianghui Gu
- Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing, 211816, China
| | - Kaichuan Wen
- Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing, 211816, China
| | - Qiming Peng
- Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing, 211816, China
| | - Wei Huang
- Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing, 211816, China
- Frontiers Science Center for Flexible Electronics (FSCFE), Shaanxi Institute of Flexible Electronics (SIFE) & Shaanxi Institute of Biomedical Materials and Engineering (SIBME), Northwestern Polytechnical University (NPU), 127 West Youyi Road, Xi'an, 710072, China
| | - Jianpu Wang
- Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing, 211816, China
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Zhang D, Huang T, Duan L. Emerging Self-Emissive Technologies for Flexible Displays. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1902391. [PMID: 31595613 DOI: 10.1002/adma.201902391] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Revised: 07/01/2019] [Indexed: 06/10/2023]
Abstract
Featuring a combination of ultrathin and lightweight properties, excellent mechanical flexibility, low power-consumption, and widely tunable saturated emission, flexible displays have opened up a new possibility for optoelectronics. The demands for flexible displays are growing on a continual basis due not only to their successful commercialization but, more importantly, their endless possibilities for wearable integrated systems. Up to now, self-emissive technologies for displays, flexible active-matrix organic light-emitting diodes (flex-AMOLED), flexible quantum dot light-emitting diodes (flex-QLEDs), and flexible perovskite light-emitting diodes (flex-PeLEDs) have been widely reported, but despite the significant progress made in these technologies, enormous obstacles and challenges remain for the vision of truly wearable applications, in particular with flex-QLEDs and flex-PeLEDs. Here, a review of the recent progress of all three self-emissive technologies for flexible displays is conducted, including the emissive active materials, device structures and approaches to manufacturing, the flexible substrates, and conductive electrodes, as well as the encapsulation techniques. The fast-paced improvement made to the efficiency of flexible devices in recent years is also summarized. The review concludes by making suggestions on the future development in this area, and is expected to help researchers in gaining a comprehensive understanding about the newly emerging technologies for flexible displays.
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Affiliation(s)
- Dongdong Zhang
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Tianyu Huang
- Center for Flexible Electronics Technology, Tsinghua University, Beijing, 100084, P. R. China
| | - Lian Duan
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
- Center for Flexible Electronics Technology, Tsinghua University, Beijing, 100084, P. R. China
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Choi J, Im HS, Kwack JH, Hwang H, Park YW, Seong TY, Ju BK. Self-catalytic-grown SnO x nanocones for light outcoupling enhancement in organic light-emitting diodes. NANOTECHNOLOGY 2020; 31:135204. [PMID: 31804223 DOI: 10.1088/1361-6528/ab5f04] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Light extraction in organic light-emitting diodes (OLEDs) was improved by applying SnO x nanocones grown via thermal annealing in a low-O2 atmosphere. SnO x was easily fabricated through thermal processing after Sn deposition. The diameter of the SnO x nanocones was controlled by changing the deposition thickness of Sn. The SnO x nanocones induced strong Mie scattering, which reduced the total internal reflection in the glass substrate. Consequently, the OLED with SnO x nanocones exhibited a 23% increase in the external quantum efficiency compared with a reference device.
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Affiliation(s)
- Junhee Choi
- Display and Nanosystem Laboratory, School of Electrical Engineering, Korea University, Seoul 02841, Republic of Korea
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