Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Jihun Park is active.

Publication


Featured researches published by Jihun Park.


Nano Letters | 2013

High-Performance, Transparent, and Stretchable Electrodes Using Graphene–Metal Nanowire Hybrid Structures

Mi Sun Lee; Kyongsoo Lee; So Yun Kim; Heejoo Lee; Jihun Park; Kwang Hyuk Choi; Han-Ki Kim; Dae Gon Kim; Dae Young Lee; SungWoo Nam; Jang-Ung Park

Transparent electrodes that can remain electrically conductive and stable under large mechanical deformations are highly desirable for applications in flexible and wearable electronics. This paper describes a comprehensive study of the electrical, optical, and mechanical properties of hybrid nanostructures based on two-dimensional graphene and networks of one-dimensional metal nanowires, and their use as transparent and stretchable electrodes. Low sheet resistance (33 Ω/sq) with high transmittance (94% in visible range), robust stability against electric breakdown and oxidation, and superb flexibility (27% in bending strain) and stretchability (100% in tensile strain) are observed, and these multiple functionalities of the hybrid structures suggest a future promise for next generation electronics. The use of hybrid electrodes to fabricate oxide semiconductor transistors and single-pixel displays integrated on wearable soft contact lenses with in vivo tests are demonstrated.


Nature Communications | 2017

Wearable smart sensor systems integrated on soft contact lenses for wireless ocular diagnostics

Joohee Kim; Minji Kim; Mi-Sun Lee; Kukjoo Kim; Sangyoon Ji; Yun-Tae Kim; Jihun Park; Kyungmin Na; Kwi-Hyun Bae; Hong Kyun Kim; Franklin Bien; Chang Young Lee; Jang-Ung Park

Wearable contact lenses which can monitor physiological parameters have attracted substantial interests due to the capability of direct detection of biomarkers contained in body fluids. However, previously reported contact lens sensors can only monitor a single analyte at a time. Furthermore, such ocular contact lenses generally obstruct the field of vision of the subject. Here, we developed a multifunctional contact lens sensor that alleviates some of these limitations since it was developed on an actual ocular contact lens. It was also designed to monitor glucose within tears, as well as intraocular pressure using the resistance and capacitance of the electronic device. Furthermore, in-vivo and in-vitro tests using a live rabbit and bovine eyeball demonstrated its reliable operation. Our developed contact lens sensor can measure the glucose level in tear fluid and intraocular pressure simultaneously but yet independently based on different electrical responses.


Nano Letters | 2014

In-situ Synthesis of Carbon Nanotube–Graphite Electronic Devices and Their Integrations onto Surfaces of Live Plants and Insects

Kyongsoo Lee; Jihun Park; Mi-Sun Lee; Joohee Kim; Byung Gwan Hyun; Dong Jun Kang; Kyungmin Na; Chang Young Lee; Franklin Bien; Jang-Ung Park

Here we report an unconventional approach for the single-step synthesis of monolithically integrated electronic devices based on multidimensional carbon structures. Integrated arrays of field-effect transistors and sensors composed of carbon nanotube channels and graphitic electrodes and interconnects were formed directly from the synthesis. These fully integrated, all-carbon devices are highly flexible and can be transferred onto both planar and nonplanar substrates, including papers, clothes, and fingernails. Furthermore, the sensor network can be interfaced with inherent life forms in nature for monitoring environmental conditions. Examples of significant applications are the integration of the devices to live plants or insects for real-time, wireless sensing of toxic gases.


Nature Communications | 2017

Integrated arrays of air-dielectric graphene transistors as transparent active-matrix pressure sensors for wide pressure ranges

Sung-Ho Shin; Sangyoon Ji; Seiho Choi; Kyoung-Hee Pyo; Byeong Wan An; Jihun Park; Joohee Kim; Ju-Young Kim; Ki-Suk Lee; Soon-Yong Kwon; Jaeyeong Heo; Byong-Guk Park; Jang-Ung Park

Integrated electronic circuitries with pressure sensors have been extensively researched as a key component for emerging electronics applications such as electronic skins and health-monitoring devices. Although existing pressure sensors display high sensitivities, they can only be used for specific purposes due to the narrow range of detectable pressure (under tens of kPa) and the difficulty of forming highly integrated arrays. However, it is essential to develop tactile pressure sensors with a wide pressure range in order to use them for diverse application areas including medical diagnosis, robotics or automotive electronics. Here we report an unconventional approach for fabricating fully integrated active-matrix arrays of pressure-sensitive graphene transistors with air-dielectric layers simply formed by folding two opposing panels. Furthermore, this realizes a wide tactile pressure sensing range from 250 Pa to ∼3 MPa. Additionally, fabrication of pressure sensor arrays and transparent pressure sensors are demonstrated, suggesting their substantial promise as next-generation electronics.


Nanoscale Research Letters | 2015

Studies on the mechanical stretchability of transparent conductive film based on graphene-metal nanowire structures

Mi-Sun Lee; Joohee Kim; Jihun Park; Jang-Ung Park

Transparent electrodes with superior flexibility and stretchability as well as good electrical and optical properties are required for applications in wearable electronics with comfort designs and high performances. Here, we present hybrid nanostructures as stretchable and transparent electrodes based on graphene and networks of metal nanowires, and investigate their optical, electrical, and mechanical properties. High electrical and optical characteristics, superb bendability (folded in half), excellent stretchability (10,000 times in stretching cycles with 100% in tensile strain toward a uniaxial direction and 30% in tensile strain toward a multi-axial direction), strong robustness against electrical breakdown and thermal oxidation were obtained through comprehensive study. We believe that these results suggest a substantial promise application in future electronics.


Polymers | 2017

Smart Sensor Systems for Wearable Electronic Devices

Byeong Wan An; Jung Hwal Shin; So-Yun Kim; Joohee Kim; Sangyoon Ji; Jihun Park; Youngjin Lee; Jiuk Jang; Young-Geun Park; Eunjin Cho; Subin Jo; Jang-Ung Park

Wearable human interaction devices are technologies with various applications for improving human comfort, convenience and security and for monitoring health conditions. Healthcare monitoring includes caring for the welfare of every person, which includes early diagnosis of diseases, real-time monitoring of the effects of treatment, therapy, and the general monitoring of the conditions of people’s health. As a result, wearable electronic devices are receiving greater attention because of their facile interaction with the human body, such as monitoring heart rate, wrist pulse, motion, blood pressure, intraocular pressure, and other health-related conditions. In this paper, various smart sensors and wireless systems are reviewed, the current state of research related to such systems is reported, and their detection mechanisms are compared. Our focus was limited to wearable and attachable sensors. Section 1 presents the various smart sensors. In Section 2, we describe multiplexed sensors that can monitor several physiological signals simultaneously. Section 3 provides a discussion about short-range wireless systems including bluetooth, near field communication (NFC), and resonance antenna systems for wearable electronic devices.


Science Advances | 2018

Soft, smart contact lenses with integrations of wireless circuits, glucose sensors, and displays

Jihun Park; Joohee Kim; So-Yun Kim; Woon Hyung Cheong; Jiuk Jang; Young-Geun Park; Kyungmin Na; Yun-Tae Kim; Jun Hyuk Heo; Chang Young Lee; Jung Heon Lee; Franklin Bien; Jang-Ung Park

This study presents a soft, smart contact lens that provides real-time sensing for diabetes through a wireless display. Recent advances in wearable electronics combined with wireless communications are essential to the realization of medical applications through health monitoring technologies. For example, a smart contact lens, which is capable of monitoring the physiological information of the eye and tear fluid, could provide real-time, noninvasive medical diagnostics. However, previous reports concerning the smart contact lens have indicated that opaque and brittle components have been used to enable the operation of the electronic device, and this could block the user’s vision and potentially damage the eye. In addition, the use of expensive and bulky equipment to measure signals from the contact lens sensors could interfere with the user’s external activities. Thus, we report an unconventional approach for the fabrication of a soft, smart contact lens in which glucose sensors, wireless power transfer circuits, and display pixels to visualize sensing signals in real time are fully integrated using transparent and stretchable nanostructures. The integration of this display into the smart lens eliminates the need for additional, bulky measurement equipment. This soft, smart contact lens can be transparent, providing a clear view by matching the refractive indices of its locally patterned areas. The resulting soft, smart contact lens provides real-time, wireless operation, and there are in vivo tests to monitor the glucose concentration in tears (suitable for determining the fasting glucose level in the tears of diabetic patients) and, simultaneously, to provide sensing results through the contact lens display.


IEEE Sensors Journal | 2016

Graphene-Based Wireless Environmental Gas Sensor on PET Substrate

Kyungmin Na; Hyunggun Ma; Jihun Park; Junho Yeo; Jang-Ung Park; Franklin Bien

Modern gas detection systems have expanded into the monitoring of greenhouse gases, which are believed to cause global warming and are toxic to the human body. This demand has led to the development of numerous different discrete and distinct sensor technologies. A wireless sensing system is formed using the integrated arrays of field-effect transistors and sensors comprising graphene channels, silver nanowire electrodes, and interconnects with a wireless communication antenna. These carbon devices are highly flexible and can be transferred onto both planar and non-planar substrates, including papers, clothes, fingernails, and human skin. The printed wireless sensing antenna senses the gases by detecting the change in the signal produced by a change in sensor resistance.


npj Flexible Electronics | 2017

Research on flexible display at ulsan national institute of science and technology

Jihun Park; Sanghyun Heo; Kibog Park; Myoung Hoon Song; Ju-Young Kim; Gyouhyung Kyung; Rodney S. Ruoff; Jang-Ung Park; Franklin Bien

Displays represent information visually, so they have become the fundamental building block to visualize the data of current electronics including smartphones. Recently, electronics have been advanced toward flexible and wearable electronics that can be bent, folded, or stretched while maintaining their performance under various deformations. Here, recent advances in research to demonstrate flexible and wearable displays are reviewed. We introduce these results by dividing them into several categories according to the components of the display: active-matrix backplane, touch screen panel, light sources, integrated circuit for fingerprint touch screen panel, and characterization tests; and we also present mechanical tests in nano-meter scale and visual ergonomics research.


Nanoscale | 2016

Wearable, wireless gas sensors using highly stretchable and transparent structures of nanowires and graphene

Jihun Park; Joohee Kim; Kukjoo Kim; So-Yun Kim; Woon Hyung Cheong; Kyeongmin Park; Joo Hyeb Song; Gyeongho Namgoong; Jae Joon Kim; Jaeyeong Heo; Franklin Bien; Jang-Ung Park

Collaboration


Dive into the Jihun Park's collaboration.

Top Co-Authors

Avatar

Jang-Ung Park

Ulsan National Institute of Science and Technology

View shared research outputs
Top Co-Authors

Avatar

Joohee Kim

Ewha Womans University

View shared research outputs
Top Co-Authors

Avatar

Franklin Bien

Ulsan National Institute of Science and Technology

View shared research outputs
Top Co-Authors

Avatar

Sangyoon Ji

Ulsan National Institute of Science and Technology

View shared research outputs
Top Co-Authors

Avatar

So-Yun Kim

Ulsan National Institute of Science and Technology

View shared research outputs
Top Co-Authors

Avatar

Kyungmin Na

Ulsan National Institute of Science and Technology

View shared research outputs
Top Co-Authors

Avatar

Byeong Wan An

Ulsan National Institute of Science and Technology

View shared research outputs
Top Co-Authors

Avatar

Jiuk Jang

Ulsan National Institute of Science and Technology

View shared research outputs
Top Co-Authors

Avatar

Ju-Young Kim

Ulsan National Institute of Science and Technology

View shared research outputs
Top Co-Authors

Avatar

Mi-Sun Lee

Ulsan National Institute of Science and Technology

View shared research outputs
Researchain Logo
Decentralizing Knowledge