A5061037745- Advanced Sensor and Energy Harvesting Materials
- Conducting polymers and applications
- Advanced Materials and Mechanics
- Nanomaterials and Printing Technologies
- Organic Light-Emitting Diodes Research
- Organic Electronics and Photovoltaics
- Interactive and Immersive Displays
- Advanced Optical Imaging Technologies
- Nanofabrication and Lithography Techniques
- Non-Invasive Vital Sign Monitoring
- Advanced optical system design
- Gas Sensing Nanomaterials and Sensors
- Semiconductor Quantum Structures and Devices
- Additive Manufacturing and 3D Printing Technologies
- Quantum Dots Synthesis And Properties
- Tactile and Sensory Interactions
- Thin-Film Transistor Technologies
- Silicone and Siloxane Chemistry
- Modular Robots and Swarm Intelligence
- Advanced Fiber Optic Sensors
- Optical Systems and Laser Technology
- Adaptive optics and wavefront sensing
- Electrowetting and Microfluidic Technologies
Seoul National University
2019-2024
The ability to image pressure distribution over complex three-dimensional surfaces would significantly augment the potential applications of electronic skin. However, existing methods show poor spatial and temporal fidelity due their limited pixel density, low sensitivity, or conformability. Here, we report an ultraflexible transparent electroluminescent skin that autonomously displays super-resolution images in real time. device comprises a pressure-sensing film with solution-processable...
Abstract A stretchable display would be the ultimate form factor for next generation of displays beyond curved and foldable configurations that have enabled commercialization deformable electronic applications. However, because conventional active devices are very brittle vulnerable to mechanical deformation, appropriate strategies must developed from material structural points view achieve desired stretchability without compromising electrical properties. In this regard, remarkable findings...
Abstract Inkjet and transfer printing processes are combined to easily form patterned poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) films as top anodes of all solution–processed inverted polymer light emitting diodes (PLEDs) on rigid glass flexible plastic substrates. An adhesive PEDOT:PSS ink is formulated fully customizable patterns obtained using the inkjet process. In order films, adhesion properties at interfaces during multistep carefully adjusted. The transferred...
Abstract Silver nanowires (AgNWs) have been considered as replacements of indium tin oxide (ITO) due to superior optoelectronic properties and mechanical stability for flexible electronics. However, high cost process complexity patterning disturb their applicability commercial products. Herein, a facile method AgNWs by using inkjet‐printed conductive polymer templates is developed, which can be applied on various surfaces including super hydrophobic light‐emitting organic layer. Combination...
Abstract Stretchable organic light‐emitting diodes (OLEDs) have been considered as a promising technology for next‐generation free‐form and wearable displays. However, an approach to ensure both high device performance resolution has not yet suggested. While introducing wrinkled structure in the active pixel areas is decent method, formation of out‐of‐plane macroscopic wrinkles having wavelength few hundred µm caused distortion shape pixel, which critical drawback matrix‐configured display...
High-fidelity patterning of thin metal films on arbitrary soft substrates promises integrated circuits and devices that can significantly augment the morphological functionalities freeform electronics. However, existing methods decisively rely prefabricated rigid masks are severely incompatible with myriad surfaces. Here, we report printable, stretchable metal-vapor-desorption layers (s-MVDLs) enable high-fidelity polymeric The printed rubbery matrix highly mobile chains effectively repels...
Seamless tiling of displays is one the key enabling technologies for next-generation large-area electronics applications. In this paper, we propose a facile method to demonstrate seamless display using cylindrical lens pair (CLP) fabricated by dispenser printing method. Optical properties printed CLP and corresponding capability concealing seam in are analyzed set luminance simulation measurement terms geometric parameters lens. The with an optimized features viewing angle concealment 40°.
Field‐effect transistor (FET)‐type pressure sensor offers excellent amplification and signal conversion functionality as a switching device, it has the capability to integrate tactile sensors by constructing active‐matrix arrays with low crosstalk. However, conventional FET‐type either have complex device layout additional components, such pressure‐sensitive elastomer, attached source/drain electrodes, or method of modulating gate dielectric can lead breakdown failure. Additionally,...
Abstract Inkjet printing that ensures superior patternability and customizability can be fully exploited as top electrodes in thin-film-based light-emitting devices. However, direct inkjet onto multi-layered thin films severely damages the underlying functional layers due to intermixing with ink solvents, resulting poor device efficiencies. Here, we report a lamination of inkjet-printed Ag cathode for polymer diodes (PLEDs). The organometallic was printed on surface-modified elastomers...
Implementing the multilayered structure on a stretchable platform is essential to realize multifunctional system beyond simply imparting stretchability single rigid device. There have been many efforts achieve vertical interconnect access (VIA) for electrical connections between two or more different layers electronics. Nevertheless, there are still challenges in implementing soft systems with VIA due high complexity of fabrication process, limitations circuit design, and poor compatibility...
Quantum-dot light-emitting diodes (QLEDs) are promising components for next-generation displays and related applications. However, their performance is critically limited by inherent hole-injection barrier caused deep highest-occupied molecular orbital levels of quantum dots. Herein, we present an effective method enhancing the QLEDs incorporating a monomer (TCTA or mCP) into hole-transport layers (HTL). The impact different concentrations on characteristics were investigated. results...
By the combination of inkjet printing PEDOT:PSS transfer template and selective silver nanowires (AgNW), AgNWs customizable transparency can be patterned with high degree freedom, without need equipment cost complicated process. The AgNW-transferred transparent electrodes exhibit both great figure merit easily tunable optoelectronic properties. With maintaining advantages overcoming issues AgNWs, method developed by Yongtaek Hong co-workers in article number 2000042 applied to various...
Stretchable polymer light-emitting diodes with an engineered microwrinkle structure are presented in article number 2000231 by Yongtaek Hong and co-workers. The formation of imperceptible structure, enabled reducing the film thickness deposited on a prestretched elastomer, suppresses distortion caused out-of-plane wavy which occurs conventional lamination approach, advancing feasibility high-resolution stretchable display.
Abstract Facile high-resolution patterning of silver nanowires (AgNWs) is a key enabling technology for expanding their usage to flexible and stretchable electronics applications. Although various methods have been proposed, only high-cost complex mask-based demonstrated potential micrometer-scale pattern-ability, which no design freedom changing patterns in facile manner. Herein, we suggest maskless method by combining an adhesive underlayer inkjet-printed conductive polymer patterns. AgNWs...
A facile method for designing and fabricating a concave mirror from 3D printed mold is proposed seamless modular curved-edge display. The placed on the seam of display, thereby reflecting images at area toward observer direction. By investigating structures based parametric modeling, we obtain continuous image in display by optically concealing seam. We also analyze luminance distribution viewing angle to show capability mirror.
Stretchable Displays In article number 2201067, Yeongjun Lee, Yongtaek Hong, Youngjun Yun, and co-workers review recent developments in advanced materials feasible strategies for the realization of stretchable electronic devices displays, which will be ultimate form factor next-generation displays. Various matrix displays as well future prospect active are discussed.
Solution-processed polymer light-emitting diodes (PLEDs) have been widely investigated in display area due to their low-cost and large-scale fabrication. Generally, order pattern the device, electrodes are deposited through a vacuum process such as sputtering or thermal evaporation. In terms of cost, inkjet printing is most promising alternative evaporation because it allows low-material consumption well free patterning electrodes. However, direct inkjet-printing on organic layers induces...
Elastomeric mirror is one of the main components systems that require tunable optical characteristics, and being applied in various devices such as zoom camera, electrostatic actuator, augmented/virtual reality (AR/VR) display. Generally, to fabricate an elastomeric mirror, a metal layer deposited on elastomer substrate by vacuum process thermal evaporation, e-beam sputtering. However, these processes can damage substrate, thereby degrading quality surface. The formed also vulnerable small...
We fabricated all solution-processed inverted polymer light emitting diodes (PLEDs) where functional layers were spin-coated on patterned-ITO glass substrates and PEDOT:PSS anodes deposited by a transfer process. The structure of our devices is ITO (cathode) / ZnO (EITL) PEI (interlayer) PDY-132 (EML) (HITL) transferred conductive (anode). Although many groups have studied PLEDs, top electrodes typically photolithography or adhesive tape, which hinders low-cost large-area mass production. In...
A key enabling technology for all‐printed organic light‐emitting diodes is printing electrodes that can be used anodes or cathodes conventional inverted device structures. In both structures, the first bottom electrodes, which are either transparent opaque depending on structure, typically printed while last top have been deposited by using a vacuum‐based evaporation process because when fabricated solution‐based process, under layers easily damaged during fabrication process. Although...
We report a facile fabrication method of curved mirror with 3D printed plastic mold. Polylactic acid (PLA) is used as material for Polydimethylsiloxane (PDMS) replica obtained from PLA mold, followed by planarization spin-coating additional PDMS. After ultraviolet (UV) treatment smoothened PDMS replica, aluminum (Al) layer deposited thermal evaporation. Due to surface Al shows clear reflected image without perceptible lines, thereby functioning mirror. expect that our will be applicable...
We report imperceptibly micro-wrinkled organic light-emitting diodes (OLEDs) to define distortion-free pixel by in-situ deposition on two-dimensionally pre-stretched polydimethylsiloxane (PDMS) substrate. The developed fabrication process includes surface engineering for a low-temperature solution process. After releasing the pre-strain, structure facilitates maintain clear shape of with wrinkle period under 20 µm that is unrecognizable human eyes, whereas wrinkles hundreds are formed when...