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93 results on '"Lee, Hayoon"'

89. The Efficacy of the Change in Belly Board Aperture Location by the Addition of Bladder Compression Device for Radiotherapy of Rectal Cancer

Author

Yoon, Hong In, primary, Chung, Yoonsun, additional, Kim, Joo Ho, additional, Park, Hyo Kuk, additional, Lee, Sang Kyu, additional, Kim, Young Suk, additional, Choi, Yunseon, additional, Kim, Misun, additional, Lee, Hayoon, additional, Chang, Jeesuk, additional, Cha, Hyejung, additional, Seong, Jinsil, additional, Keum, Ki Chang, additional, and Koom, Woong Sub, additional

Published
2010
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91. Enhanced Optical and Thermal Properties of a Novel Yellow Quinophthalone Derivative for Color Filter Colorants in Image Sensors.

Author

Park, Sunwoo, Godi, Mahendra, Khairnar, Nikita, Dae, Sunwoo, Kwon, Hyukmin, Park, Sangwook, Lee, Hayoon, Lee, Kiho, and Park, Jongwook

Abstract

Herein, the design and synthesis of novel yellow quinophthalone derivatives, 4,5,6,7‐tetrachloro‐2‐(6‐chloro‐2‐(3‐hydroxy‐1‐oxo‐1H‐cyclopenta[b]naphthalen‐2‐yl)quinolin‐4‐yl)isoindoline‐1,3‐dione (pC‐QP) and 4,5,6,7‐tetrachloro‐2‐(7‐chloro‐2‐(3‐hydroxy‐1‐oxo‐1H‐cyclopenta[b]naphthalen‐2‐yl)quinolin‐4‐yl)isoindoline‐1,3‐dione (mC‐QP), are used for use as yellow colorants in image sensors. The synthesized compounds are designed to modulate the optical properties based on the substituted positions of the chloride group within the quinophthalone structure. The solubility of pC‐QP and mC‐QP in propylene glycol monomethyl ether acetate solvent is found to be 0.08 and 0.15 wt%, respectively. The molar extinction coefficient values of pC‐QP and mC‐QP in solution are determined to be 3.14 × 104 and 3.62 × 105 L mol−1 cm−1, respectively. The transmittance of mC‐QP meets commercial requirements, exhibiting less than 0.3% between 412 and 475 nm and over 91% above 530 nm. Both pC‐QP and mC‐QP demonstrate high thermal stability with decomposition temperatures of 464 and 393 °C, respectively. As a result, mC‐QP emerges as an excellent candidate material for use as a yellow colorant in image sensors due to its outstanding properties. [ABSTRACT FROM AUTHOR]

Published
2024
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92. Novel halogenated cyclopentadienyl hafnium precursor for atomic layer deposition of high-performance HfO 2 thin film.

Author

Park S, Choi Y, Park S, Lee H, Lee K, Park J, and Jeon W

Abstract

High dielectric constant (high- k ) materials play a crucial role in modern electronics, particularly in semiconductor applications such as transistor gate insulators and dielectrics in metal-insulator-metal (MIM) capacitors. However, achieving optimal crystallinity and suppressing interfacial layer formation during deposition processes remain key challenges. To address these challenges, this study introduces a novel approach using atomic layer deposition (ALD) with a new Hf precursor incorporating an iodo ligand. The synthesized precursor, IHf, demonstrates enhanced thermal stability and reactivity, leading to superior film properties. ALD deposition of HfO 2 thin films using IHf yields excellent crystallinity and effectively inhibits interfacial layer formation, resulting in enhanced capacitance density and improved leakage current characteristics in MIM capacitors. Notably, IHf-deposited HfO 2 films exhibit a significant reduction in leakage current, achieving an equivalent oxide thickness of 1.73 nm at a leakage current density of 7.02 × 10 -8 A cm -2 @ +0.8 V. These findings highlight the potential of IHf as a promising precursor for high-performance electronic device fabrication, paving the way for advancements in semiconductor technology., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Published
2024
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93. Indolo[3,2,1- jk ]carbazole-Derived Narrowband Violet-Blue Fluorophores: Tuning the Optical and Electroluminescence Properties by Chromophore Juggling.

Author

Konidena RK, Oh S, Kang S, Park SS, Lee H, and Park J

Abstract

The development of rigid polyaromatic building blocks for narrowband violet fluorophores has received tremendous attention. Herein, we designed and synthesized two new triangle-shaped rigid building blocks, namely, 2,5-di- tert -butylindolo[3,2,1- jk ]carbazole ( tBuICz ) and 2,11-di- tert -butylindolo[3,2,1- jk ]carbazole-4-carbonitrile ( tBuICzCN ), and tethered them with different chromophores to yield a series of violet-blue fluorophores, viz. , ICzTPA-ICzPICN , and studied their structure-function relationship. The appended chromophores and cyano unit played a vital role in controlling the optical and electrical properties of the compounds. Except triphenylamine-substituted derivatives, the compounds showed pure violet emission (λ em ≤ 403 nm). Intriguingly, the compounds exhibited narrow-band emission with a full-width at half-maximum ≤ 40 nm, attributed to the rigidity of the ICz core. The emission of the compounds displayed positive solvatochromism, which is ascribed to the photoinduced intramolecular charge transfer in the excited state. The compounds revealed excellent thermal robustness with T 5d ≥ 363 °C. The triphenylamine-featuring derivatives displayed a high-lying HOMO compared to their congeners due to their electron-rich nature. When we applied these materials in organic light-emitting diodes, ICzPI outperformed in the series with an EQE max of 3.07% and a current efficiency of 1.04 cd/A. Notably, its CIEy ∼ 0.046 precisely matched with the Rec.2020 standard of deep-blue color (CIEy ∼ 0.046).

Published
2022
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