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Choi C, Schlenker E, Ha H, Cheong JY, Hwang B. Versatile Applications of Silver Nanowire-Based Electrodes and Their Impacts. MICROMACHINES 2023; 14:562. [PMID: 36984976 PMCID: PMC10055823 DOI: 10.3390/mi14030562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 02/25/2023] [Accepted: 02/25/2023] [Indexed: 06/18/2023]
Abstract
Indium tin oxide (ITO) is currently the most widely used material for transparent electrodes; however, it has several drawbacks, including high cost, brittleness, and environmental concerns. Silver nanowires (AgNWs) are promising alternatives to ITO as materials for transparent electrodes owing to their high electrical conductivity, transparency in the visible range of wavelengths, and flexibility. AgNWs are effective for various electronic device applications, such as touch panels, biosensors, and solar cells. However, the high synthesis cost of AgNWs and their poor stability to external chemical and mechanical damages are significant challenges that need to be addressed. In this review paper, we discuss the current state of research on AgNW transparent electrodes, including their synthesis, properties, and potential applications.
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Affiliation(s)
- Chunghyeon Choi
- School of Integrative Engineering, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Erik Schlenker
- College of Health, Science and Technology at University of Illinois Springfield, One University Plaza, Springfield, IL 62703, USA
| | - Heebo Ha
- School of Integrative Engineering, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Jun Young Cheong
- Bavarian Center for Battery Technology (BayBatt) and Department of Chemistry, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
| | - Byungil Hwang
- School of Integrative Engineering, Chung-Ang University, Seoul 06974, Republic of Korea
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Hossain M, Santra PK. Spray coated micropatterning of metal halide perovskite for anticounterfeiting fluorescent tags. NANOTECHNOLOGY 2022; 34:025301. [PMID: 36191474 DOI: 10.1088/1361-6528/ac96f6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 10/03/2022] [Indexed: 06/16/2023]
Abstract
Metal halide perovskites possess exciting optoelectronic properties and are being used for various applications, including fluorescent anticounterfeiting security tags. The existing anticounterfeitings based on perovskites have a reversible transition that does not allow to know whether the information is tampered or compromised. In this work, we developed fluorescent anticounterfeiting security tags using micropatterned metal halide perovskite nanocrystals. The micro features were created by spray coating of stabilized methylammonium lead tribromide (MAPbBr3) nanocrystals (NCs) in polystyrene (PS) solution, which has a proper wettability to various rigid and flexible substrates. The PS provides additional optical and structural stability to the MAPbBr3NCs against polar solvents. By combining stable and unstable MAPbBr3nanocrystals, we created a double-layer fluorescent anticounterfeiting security tag, and the information is hidden under both ambient light and UV illumination. An irreversible decryption is possible after treating the security tags with particular solvents, thus tampering of the security tag is easily detectable.
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Affiliation(s)
- Modasser Hossain
- Centre for Nano and Soft Matter Sciences (CeNS), Bengaluru-562162, India
- Manipal Academy of Higher Education (MAHE), Manipal-576104, India
| | - Pralay K Santra
- Centre for Nano and Soft Matter Sciences (CeNS), Bengaluru-562162, India
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Yu JS, Kim JH. Hacking detection based on the elastic properties of liquid crystals in different phases. OPTICS EXPRESS 2021; 29:39352-39361. [PMID: 34809301 DOI: 10.1364/oe.441941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 10/31/2021] [Indexed: 06/13/2023]
Abstract
We present a security device that can detect and block hacking using the characteristics of liquid crystals. This device is based on a liquid crystal cell consisting of a uniformly aligned layer and a photo-alignment layer. To inscribe a pattern, the device is illuminated when the liquid crystal is in the smectic phase. The resulting image is invisible after light irradiation. Heating to the nematic phase improves this alignment and reveals the recorded pattern. Returning to the smectic phase distorts the pattern. Because the pattern is not shown without heating and the trace of the pattern does not disappear once viewed, it is possible to detect whether data has been hacked. The device is easy to fabricate, cost-effective, and sensitive to outside intrusion.
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Jung C, Kim G, Jeong M, Jang J, Dong Z, Badloe T, Yang JKW, Rho J. Metasurface-Driven Optically Variable Devices. Chem Rev 2021; 121:13013-13050. [PMID: 34491723 DOI: 10.1021/acs.chemrev.1c00294] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Optically variable devices (OVDs) are in tremendous demand as optical indicators against the increasing threat of counterfeiting. Conventional OVDs are exposed to the danger of fraudulent replication with advances in printing technology and widespread copying methods of security features. Metasurfaces, two-dimensional arrays of subwavelength structures known as meta-atoms, have been nominated as a candidate for a new generation of OVDs as they exhibit exceptional behaviors that can provide a more robust solution for optical anti-counterfeiting. Unlike conventional OVDs, metasurface-driven OVDs (mOVDs) can contain multiple optical responses in a single device, making them difficult to reverse engineered. Well-known examples of mOVDs include ultrahigh-resolution structural color printing, various types of holography, and polarization encoding. In this review, we discuss the new generation of mOVDs. The fundamentals of plasmonic and dielectric metasurfaces are presented to explain how the optical responses of metasurfaces can be manipulated. Then, examples of monofunctional, tunable, and multifunctional mOVDs are discussed. We follow up with a discussion of the fabrication methods needed to realize these mOVDs, classified into prototyping and manufacturing techniques. Finally, we provide an outlook and classification of mOVDs with respect to their capacity and security level. We believe this newly proposed concept of OVDs may bring about a new era of optical anticounterfeit technology leveraging the novel concepts of nano-optics and nanotechnology.
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Affiliation(s)
- Chunghwan Jung
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Gyeongtae Kim
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Minsu Jeong
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Jaehyuck Jang
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Zhaogang Dong
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 138634, Singapore
| | - Trevon Badloe
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Joel K W Yang
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 138634, Singapore.,Engineering Product Development, Singapore University of Technology and Design, 487372, Singapore
| | - Junsuk Rho
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea.,Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea.,POSCO-POSTECH-RIST Convergence Research Center for Flat Optics and Metaphotonics, Pohang 37673, Republic of Korea
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