Sangyoon Lee

Dr. Sangyoon Lee

Korea Advanced Institute of Science and Technology
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orcid

Research Focus & Metrics

Academic Career Length

23Years (2004-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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7 July 2011 in Advanced Materials
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Journal Article
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SKSunkook Kim
Sunkook Kim
Hyuk-Jun KwonHyuk-Jun Kwon
Hyuk-Jun Kwon
SLSunghun Lee
Sunghun Lee
HSHongshik Shim
Hongshik Shim
YCYoungtea Chun
Youngtea Chun
Sangyoon LeeSangyoon Lee
Sangyoon Lee

15 March 2013 in Scientific Reports
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Journal Article
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HKHyun-Suk Kim
Hyun-Suk Kim
SJSang Ho Jeon
Sang Ho Jeon
JPJoon Seok Park
Joon Seok Park
TKTae Sang Kim
Tae Sang Kim
KSKyoung Seok Son
Kyoung Seok Son
KKKinam Kim
Kinam Kim
Ultra-definition, large-area displays with three-dimensional visual effects represent megatrend in the current/future display industry. On the hardware level, such a “dream” display requires faster pixel switching and higher driving current, which in turn necessitate thin-film transistors (TFTs) with high mobility. Amorphous oxide semiconductors (AOS) such as In-Ga-Zn-O are poised to enable such TFTs, but the trade-off between device performance and stability under illumination critically limits their usability, which is related to the hampered electron-hole recombination caused by the oxygen vacancies. Here we have improved the illumination stability by substituting oxygen with nitrogen in ZnO, which may deactivate oxygen vacancies by raising valence bands above the defect levels. Indeed, the stability under illumination and electrical bias is superior to that of previous AOS-based TFTs. By achieving both mobility and stability, it is highly expected that the present ZnON TFTs will be extensively deployed in next-generation flat-panel displays.

23 March 2017 in Advanced Science
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Journal Article
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SISoo‐Ghang Ihn
Soo‐Ghang Ihn
NLNamheon Lee
Namheon Lee
SJSoon Ok Jeon
Soon Ok Jeon
MSMyungsun Sim
Myungsun Sim
HKHosuk Kang
Hosuk Kang
Sangyoon LeeSangyoon Lee
Sangyoon Lee
It has been challenging to find stable blue organic light emitting diodes (OLEDs) that rely on thermally activated delayed fluorescence (TADF). Lack of stable host materials well‐fitted to the TADF emitters is one of the critical reasons. The most popular host for blue TADF, bis[2‐(diphenylphosphino)phenyl] ether oxide (DPEPO), leads to unrealistically high maximum external quantum efficiency. DPEPO is however an unstable material and has a poor charge transporting ability, which in turn induces an intrinsic short OLED operating lifespan. Here, an alternative host material is introduced which educes the potential efficiency and device lifespan of given TADF emitters with the appropriateness of replacing the most popular host material, DPEPO, in developing blue TADF emitters. It simultaneously provides much longer device lifespan and higher external quantum efficiency at a practical brightness due to its high material stability and electron‐transport‐type character well‐fitted for hole‐transport‐type TADF emitters.

12 January 2015 in Scientific Reports
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Journal Article
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SLSeon-Jeong Lim
Seon-Jeong Lim
DLDong-Seok Leem
Dong-Seok Leem
KPKyung-Bae Park
Kyung-Bae Park
KKKyu-Sik Kim
Kyu-Sik Kim
SSSangchul Sul
Sangchul Sul
Sangyoon LeeSangyoon Lee
Sangyoon Lee
Complementary metal–oxide–semiconductor (CMOS) colour image sensors are representative examples of light-detection devices. To achieve extremely high resolutions, the pixel sizes of the CMOS image sensors must be reduced to less than a micron, which in turn significantly limits the number of photons that can be captured by each pixel using silicon (Si)-based technology (i.e., this reduction in pixel size results in a loss of sensitivity). Here, we demonstrate a novel and efficient method of increasing the sensitivity and resolution of the CMOS image sensors by superposing an organic photodiode (OPD) onto a CMOS circuit with Si photodiodes, which consequently doubles the light-input surface area of each pixel. To realise this concept, we developed organic semiconductor materials with absorption properties selective to green light and successfully fabricated highly efficient green-light-sensitive OPDs without colour filters. We found that such a top light-receiving OPD, which is selective to specific green wavelengths, demonstrates great potential when combined with a newly designed Si-based CMOS circuit containing only blue and red colour filters. To demonstrate the effectiveness of this state-of-the-art hybrid colour image sensor, we acquired a real full-colour image using a camera that contained the organic-on-Si hybrid CMOS colour image sensor.

8 August 2005 in Advanced Materials
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Journal Article
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TLT.‐W. Lee
T.‐W. Lee
YBY. Byun
Y. Byun
BKB.‐W. Koo
B.‐W. Koo
IKI.‐N. Kang
I.‐N. Kang
YLY.‐Y. Lyu
Y.‐Y. Lyu
Sangyoon LeeSangyoon Lee
Sangyoon Lee

28 June 2010 in Applied Physics Letters
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Journal Article
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JPJoon Seok Park
Joon Seok Park
TKTae Sang Kim
Tae Sang Kim
KSKyoung Seok Son
Kyoung Seok Son
KLKwang-Hee Lee
Kwang-Hee Lee
WMWan-Joo Maeng
Wan-Joo Maeng
Sangyoon LeeSangyoon Lee
Sangyoon Lee
The stability of hafnium indium zinc oxide thin film transistors under negative bias stress with simultaneous exposure to white light was evaluated. Two different inverted staggered bottom gate devices, each with a silicon oxide and a silicon nitride passivation, were compared. The latter exhibits higher field effect mobility but inferior subthreshold swing, and undergoes more severe shifts in threshold voltage (VT) during negative bias illumination stress. The time evolution of VT fits the stretched exponential equation, which implies that hydrogen incorporation during the nitride growth has generated bulk defects within the semiconductor and/or at the semiconductor/gate dielectric interface.