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Park CH, Kang SW, Jung SG, Lee DJ, Park YW, Ju BK. Enhanced light extraction efficiency and viewing angle characteristics of microcavity OLEDs by using a diffusion layer. Sci Rep 2021; 11:3430. [PMID: 33564021 PMCID: PMC7873264 DOI: 10.1038/s41598-021-82753-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 01/19/2021] [Indexed: 11/20/2022] Open
Abstract
The viewing angle characteristics and light extraction efficiency of organic light-emitting diodes (OLEDs) with a micro-cavity structure were enhanced. This was accomplished by inserting a diffusion layer composed of nano-sized structures of a transparent polymer poly(methyl methacrylate) (PMMA) combined with a zinc oxide (ZnO) semi-planarization layer with a high refractive index (n = 2.1) into the devices. The PMMA nanostructures were fabricated by employing a reactive ion etching (RIE) process. The height and density of the PMMA nanostructures were controlled by varying the speed at which the PMMA was spin-coated onto the substrate. The insertion of the diffusion layer into the micro-cavity OLEDs (MC-OLEDs) improved the external quantum efficiency (EQE) by as much as 17% when compared to that of a MC-OLED without a diffusion layer. Furthermore, adjustment of the viewing angle from 0° to 60° halved the peak shift distance of the electroluminescence (EL) spectra from 42 to 20 nm. Additionally, changing the viewing angle from 0° to 60° changed the color coordinate movement distance of the MC-OLED with the diffusion layer to 0.078, less than half of the distance of the MC-OLED without the diffusion layer (0.165).
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Affiliation(s)
- Cheol Hwee Park
- Display and Nanosystem Laboratory, Department of Electrical Engineering, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
| | - Shin Woo Kang
- Display and Nanosystem Laboratory, Department of Electrical Engineering, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea.,Nano and Organic-Electronics Laboratory, Department of Display and Semiconductor Engineering, Sun Moon University, Asan, Chungcheongnam-do, 31460, Republic of Korea
| | - Sun-Gyu Jung
- Display and Nanosystem Laboratory, Department of Electrical Engineering, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
| | - Dong Jun Lee
- Display and Nanosystem Laboratory, Department of Electrical Engineering, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
| | - Young Wook Park
- Nano and Organic-Electronics Laboratory, Department of Display and Semiconductor Engineering, Sun Moon University, Asan, Chungcheongnam-do, 31460, Republic of Korea.
| | - Byeong-Kwon Ju
- Display and Nanosystem Laboratory, Department of Electrical Engineering, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea.
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Microchannel Fabrication in Fused Quartz by Backside Laser-Induced Plasma Ablation Using 248 nm KrF Excimer Laser. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9245320] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Laser-induced plasma ablation (LIPA) using a 248 nm KrF excimer laser was investigated for microchannel fabrication. Examination of the morphology in relation to ablation performance was emphasized, and a synthetic LIPA mechanism model was proposed based on the results. Backside LIPA with a metal target on the bottom can be attributed to a combination of two phenomena: laser-induced plasma vaporization thermal ablation from the metal target below and enhanced laser–glass direct interaction from the plasma residuum. The laser absorption enhancement of quartz substrate resulting from the metal residuum was validated clearly using absorption spectrum measurements. The influence of laser parameters on the etching quality during LIPA was also analyzed for processing optimization. Finally, fused quartz glass microchannels of outstanding surface quality and dimension uniformity were implemented. The channel depth was 28 μm, and the bottom surface roughness was better than several hundred nanometers.
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Park CH, Kim JG, Jung SG, Lee DJ, Park YW, Ju BK. Optical characteristics of refractive-index-matching diffusion layer in organic light-emitting diodes. Sci Rep 2019; 9:8690. [PMID: 31213613 PMCID: PMC6581959 DOI: 10.1038/s41598-019-45000-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 05/17/2019] [Indexed: 11/09/2022] Open
Abstract
We developed a diffusion layer with a refractive index-matching layer added to a transparent nanoscale polymer-based structure to obtain its effective scattering effects. The diffusion layer had higher haze when the refractive index-matching layer to a higher refractive index was used. This diffusion layer was applied to conventional organic light-emitting diodes (OLEDs) and micro-cavity OLEDs (MC-OLEDs) to evaluate the characteristics. When a diffusion layer was applied to conventional OLEDs, the external quantum efficiency (EQE) was 31.1% higher than that of the device without a diffusion layer due to the reduction of the substrate mode, and the viewing angle characteristic was also improved. Then, when the diffusion layer was applied to the MC-OLEDs, all devices showed similar EQE values regardless of the presence or absence of the diffusion layer, and the viewing-angle-dependent characteristics were greatly improved by the diffusion layer. Furthermore, when the diffusion layer was used with polarizer film, the black color implementation was not affected by the polarizer film, proving that it is applicable to actual OLED display products.
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Affiliation(s)
- Cheol Hwee Park
- Display and Nanosystem Laboratory, School of Electrical Engineering, Korea University Seoul, Seoul, 136-713, Republic of Korea
| | - Jae Geun Kim
- Display and Nanosystem Laboratory, School of Electrical Engineering, Korea University Seoul, Seoul, 136-713, Republic of Korea
| | - Sun-Gyu Jung
- Display and Nanosystem Laboratory, School of Electrical Engineering, Korea University Seoul, Seoul, 136-713, Republic of Korea
| | - Dong Jun Lee
- Display and Nanosystem Laboratory, School of Electrical Engineering, Korea University Seoul, Seoul, 136-713, Republic of Korea
| | - Young Wook Park
- School of Mechanical and ICT Convergence Engineering, SUN MOON University, Chungcheongnam-do, 31460, Republic of Korea.
| | - Byeong-Kwon Ju
- Display and Nanosystem Laboratory, School of Electrical Engineering, Korea University Seoul, Seoul, 136-713, Republic of Korea.
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Abstract
We report on the fabrication of sub-micro and nanostructured steel mold inserts for the replication of nanostructured immunoassay biochips. Planar and microstructured stainless steel inserts were textured at the sub-micron and nanoscale by combining nanosphere lithography and electrochemical etching. This allowed the fabrication of structures with lateral dimensions of hundreds of nanometers and aspect ratios of up to 1:2. Nanostructured plastic parts were produced by means of hot embossing and injection molding. Surface nanostructuring was used to control wettability and increase the sensitivity of an immunoassay.
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Sharma H, Wood JB, Lin S, Corn R, Khine M. Shrink-induced silica multiscale structures for enhanced fluorescence from DNA microarrays. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:10979-83. [PMID: 25191785 PMCID: PMC4172299 DOI: 10.1021/la501123b] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 08/08/2014] [Indexed: 05/22/2023]
Abstract
We describe a manufacturable and scalable method for fabrication of multiscale wrinkled silica (SiO2) structures on shrink-wrap film to enhance fluorescence signals in DNA fluorescence microarrays. We are able to enhance the fluorescence signal of hybridized DNA by more than 120 fold relative to a planar glass slide. Notably, our substrate has improved detection sensitivity (280 pM) relative to planar glass slide (11 nM). Furthermore, this is accompanied by a 30-45 times improvement in the signal-to-noise ratio (SNR). Unlike metal enhanced fluorescence (MEF) based enhancements, this is a far-field and uniform effect based on surface concentration and photophysical effects from the nano- to microscale SiO2 structures. Notably, the photophysical effects contribute an almost 2.5 fold enhancement over the concentration effects alone. Therefore, this simple and robust method offers an efficient technique to enhance the detection capabilities of fluorescence based DNA microarrays.
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Affiliation(s)
- Himanshu Sharma
- Department
of Chemical Engineering & Materials Science, Department of Chemistry, and Department of
Biomedical Engineering, University of California,
Irvine, Irvine, California 92697, United States
| | - Jennifer B. Wood
- Department
of Chemical Engineering & Materials Science, Department of Chemistry, and Department of
Biomedical Engineering, University of California,
Irvine, Irvine, California 92697, United States
| | - Sophia Lin
- Department
of Chemical Engineering & Materials Science, Department of Chemistry, and Department of
Biomedical Engineering, University of California,
Irvine, Irvine, California 92697, United States
| | - Robert
M. Corn
- Department
of Chemical Engineering & Materials Science, Department of Chemistry, and Department of
Biomedical Engineering, University of California,
Irvine, Irvine, California 92697, United States
| | - Michelle Khine
- Department
of Chemical Engineering & Materials Science, Department of Chemistry, and Department of
Biomedical Engineering, University of California,
Irvine, Irvine, California 92697, United States
- E-mail:
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Kim JS, Jeong HW, Lee W, Park BG, Kim BM, Lee KB. A simple and fast fabrication of a both self-cleanable and deep-UV antireflective quartz nanostructured surface. NANOSCALE RESEARCH LETTERS 2012; 7:430. [PMID: 22853428 PMCID: PMC3552822 DOI: 10.1186/1556-276x-7-430] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Accepted: 06/06/2012] [Indexed: 06/01/2023]
Abstract
Both self-cleanability and antireflectivity were achieved on quartz surfaces by forming heptadecafluoro-1,1,2,2-tetrahydrodecyltrichlorosilane self-assembled monolayer after fabrication of nanostructures with a mask-free method. By exposing polymethylmethacrylate spin-coated quartz plates to O2 reactive ion etching (RIE) and CF4 RIE successively, three well-defined types of nanopillar arrays were generated: A2, A8, and A11 patterns with average pillar widths of 33 ± 4 nm, 55 ± 5 nm, and 73 ± 14 nm, respectively, were formed. All the fabrication processes including the final cleaning can be finished within 4 h. All nanostructured quartz surfaces exhibited contact angles higher than 155° with minimal water droplet adhesiveness and enhanced transparency (due to antireflectivity) over a broad spectral range from 350 to 900 nm. Furthermore, A2 pattern showed an enhanced antireflective effect that extends to the deep-UV range near 190 nm, which is a drawback region in conventional thin-film-coating approaches as a result of thermal damage. Because, by changing the conditions of successive RIE, the geometrical configurations of nanostructure arrays can be easily modified to meet specific needs, the newly developed fabrication method is expected to be applied in various optic and opto-electrical areas.PACS codes: 06.60.Ei; 81.65.Cf; 81.40.Vw.
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Affiliation(s)
- Jung Suk Kim
- Department of Biomedical Engineering, College of Medicine, Korea University, Seoul, 136-701, Korea
| | - Hyun Woo Jeong
- Department of Interdisciplinary Bio/Micro System Technology, College of Engineering, Korea University, Seoul, 136-701, Korea
| | - Wonbae Lee
- Department of Biomedical Engineering, College of Health Science, Korea University, San 1, Jeongneung-3-dong, Seongbuk-gu, Seoul, 136-703, Korea
- Research Institute of Health Science, Korea University, San 1, Jeongneung-3-dong, Seongbuk-gu, Seoul, 136-703, Republic of Korea
| | - Bo Gi Park
- Department of Interdisciplinary Bio/Micro System Technology, College of Engineering, Korea University, Seoul, 136-701, Korea
| | - Beop Min Kim
- Department of Interdisciplinary Bio/Micro System Technology, College of Engineering, Korea University, Seoul, 136-701, Korea
- Department of Biomedical Engineering, College of Health Science, Korea University, San 1, Jeongneung-3-dong, Seongbuk-gu, Seoul, 136-703, Korea
| | - Kyu Back Lee
- Department of Interdisciplinary Bio/Micro System Technology, College of Engineering, Korea University, Seoul, 136-701, Korea
- Department of Biomedical Engineering, College of Health Science, Korea University, San 1, Jeongneung-3-dong, Seongbuk-gu, Seoul, 136-703, Korea
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Lee SJ, Tatavarty R, Gu MB. Electrospun polystyrene-poly(styrene-co-maleic anhydride) nanofiber as a new aptasensor platform. Biosens Bioelectron 2012; 38:302-7. [PMID: 22776178 DOI: 10.1016/j.bios.2012.06.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Revised: 06/02/2012] [Accepted: 06/06/2012] [Indexed: 11/20/2022]
Abstract
Here, we report the use of an aptamer-immobilized electrospun polystyrene-poly(styrene-co-maleic anhydride) (PS-PSMA) nanofiber as a new aptasensor platform for protein detection. Two thrombin-binding aptamers (TBA29 and TBA15) were used as a model platform to facilitate efficient detection of thrombin in a sandwich manner. Thrombin concentration was measured by fluorescence microscopy and spectroscopy, in which aptamers were labeled with either fluorescein dye or quantum dots. The results indicated that thrombin was captured uniformly on the surface of the nanofiber. Using this sandwich-type biosensor, the minimum detectable concentration of thrombin was 10 pM, with a dynamic range of 0.1-50 nM, when quantum dots were used for labeling. In contrast, the limit of detection was 1 nM, with a dynamic range of 10-200 nM, when using fluorescein dye labeling. This aptamers-on-nanofiber-based biosensor showed 2500-fold higher sensitivity than a 96-microwell plate format, attributed mainly to the large surface area of the nanofibers. In addition, this novel platform also exhibited similar high sensitivity in the detection of exogenously added thrombin in diluted human serum. This aptamers-on-nanofiber system, which is competitive with other sensing platforms and clinically meaningful in terms of its detection limit, is expected to be useful for the detection of various other targets because of its ease of application and manipulation.
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Affiliation(s)
- Su Jin Lee
- College of Life Sciences and Biotechnology, Korea University Anam-Dong, Seongbuk-Gu, Seoul 136-701, Republic of Korea
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Lee SK, Kim GS, Wu Y, Kim DJ, Lu Y, Kwak M, Han L, Hyung JH, Seol JK, Sander C, Gonzalez A, Li J, Fan R. Nanowire substrate-based laser scanning cytometry for quantitation of circulating tumor cells. NANO LETTERS 2012; 12:2697-704. [PMID: 22646476 PMCID: PMC3381426 DOI: 10.1021/nl2041707] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
We report on the development of a nanowire substrate-enabled laser scanning imaging cytometry for rare cell analysis in order to achieve quantitative, automated, and functional evaluation of circulating tumor cells. Immuno-functionalized nanowire arrays have been demonstrated as a superior material to capture rare cells from heterogeneous cell populations. The laser scanning cytometry method enables large-area, automated quantitation of captured cells and rapid evaluation of functional cellular parameters (e.g., size, shape, and signaling protein) at the single-cell level. This integrated platform was first tested for capture and quantitation of human lung carcinoma cells from a mixture of tumor cells and leukocytes. We further applied it to the analysis of rare tumor cells spiked in fresh human whole blood (several cells per mL) that emulate metastatic cancer patient blood and demonstrated the potential of this technology for analyzing circulating tumor cells in the clinical settings. Using a high-content image analysis algorithm, cellular morphometric parameters and fluorescence intensities can be rapidly quantitated in an automated, unbiased, and standardized manner. Together, this approach enables informative characterization of captured cells in situ and potentially allows for subclassification of circulating tumor cells, a key step toward the identification of true metastasis-initiating cells. Thus, this nanoenabled platform holds great potential for studying the biology of rare tumor cells and for differential diagnosis of cancer progression and metastasis.
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Affiliation(s)
- Sang-Kwon Lee
- Department of Biomedical Engineering, Yale University, New Haven, CT 06511, USA
- Department of Semiconductor Science and Technology, Chonbuk National University, Jeonju 561-756, Korea
| | - Gil-Sung Kim
- Department of Semiconductor Science and Technology, Chonbuk National University, Jeonju 561-756, Korea
| | - Yu Wu
- Department of Biomedical Engineering, Yale University, New Haven, CT 06511, USA
| | - Dong-Joo Kim
- Department of Semiconductor Science and Technology, Chonbuk National University, Jeonju 561-756, Korea
| | - Yao Lu
- Department of Biomedical Engineering, Yale University, New Haven, CT 06511, USA
| | - Minsuk Kwak
- Department of Biomedical Engineering, Yale University, New Haven, CT 06511, USA
| | - Lin Han
- Department of Biomedical Engineering, Yale University, New Haven, CT 06511, USA
| | - Jung-Hwan Hyung
- Department of Semiconductor Science and Technology, Chonbuk National University, Jeonju 561-756, Korea
| | - Jin-Kyeong Seol
- Department of Semiconductor Science and Technology, Chonbuk National University, Jeonju 561-756, Korea
| | - Chantal Sander
- Department of Biomedical Engineering, Yale University, New Haven, CT 06511, USA
| | - Anjelica Gonzalez
- Department of Biomedical Engineering, Yale University, New Haven, CT 06511, USA
| | - Jie Li
- Department of Neuropathology, Yale School of Medicine, New Haven, CT 06520, USA
| | - Rong Fan
- Department of Biomedical Engineering, Yale University, New Haven, CT 06511, USA
- Yale Comprehensive Cancer Center, New Haven, CT 06520, USA
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