• Title/Summary/Keyword: 나노과학

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Theoretical Investigation for the Adsorption of Atmospheric Harmful Gases on the Germanene Sheet (게르마닌 시트의 대기오염 기체 흡착에 대한 이론적 연구)

  • Seo, Hyun-Il;Kim, DongHyun;Baek, SooJin;Shin, ChangHo;Kim, SeungJoon
    • Journal of the Korean Chemical Society
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    • v.64 no.6
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    • pp.334-344
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    • 2020
  • The adsorption of various atmospheric harmful gases (COx, NOx, SOx) on graphene-like Germanene 2D sheet was theoretically investigated using density functional theory(DFT) method. The structures were fully optimized at the B3LYP/cc-pvDZ and CAM-B3LYP/cc-pvDZ levels of theory and confirmed to be a local minimum by the calculation of the harmonic vibrational frequencies. The adsorptions of gases on the Germanene sheet were predicted to be a physisorption process for CO, CO2, NO, and SO2 gases but to be a chemisorption process for NO2, SO, and SO2 gases.

Optical Properties of Silicon Oxide (SiOx, x<2) Thin Films Deposited by PECVD Technique (PECVD 방법으로 증착한 SiOx(x<2) 박막의 광학적 특성 규명)

  • Kim, Youngill;Park, Byoung Youl;Kim, Eunkyeom;Han, Munsup;Sok, Junghyun;Park, Kyoungwan
    • Korean Journal of Metals and Materials
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    • v.49 no.9
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    • pp.732-738
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    • 2011
  • Silicon oxide thin films were deposited by using a plasma-enhanced chemical-vapor deposition technique to investigate the light emission properties. The photoluminescence characteristics were divided into two categories along the relative ratio of the flow rates of $SiH_4$ and $N_2O$ source gases, which show light emission in the broad/visible range and a light emission peak at 380 nm. We attribute the broad/visible light emission and the light emission peak to the quantum confinement effect of nanocrystalline silicon and the Si=O defects, respectively. Changes in the photoluminescence spectra were observed after the post-annealing processes. The photoluminescence spectra of the broad light emission in the visible range shifted to the long wavelength and were saturated above an annealing temperature of $900^{\circ}C$ or after 1 hour annealing at $970^{\circ}C$. However, the position of the light emission peak at 380 nm did not change at all after the post-annealing processes. The light emission intensities at 380 nm initially increased, and decreased at annealing temperatures above $700^{\circ}C$ or after 1 hour annealing at $700^{\circ}C$. The photoluminescence behaviors after the annealing processes can be explained bythe size change of the nanocrystalline silicon and the density change of Si=O defect in the films, respectively. These results support the possibility of using a silicon-based light source for Si-optoelectronic integrated circuits and/or display devices.

Effect of proton concentration in TEOS to improve durability of hydrophilic and high light transmittance properties of nanosilica coating (친수 및 높은 광투과 기능을 함유한 나노실리카 코팅액의 내구성 향상을 위한 수소이온 농도에 따른 TEOS의 반응 연구)

  • Lee, Soo;Chan, Sung Il;Hwang, Heon
    • Journal of the Korean Applied Science and Technology
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    • v.33 no.3
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    • pp.483-491
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    • 2016
  • Even though the antifogging property of nanosilica coated glass surface is highly increased due to the hydrophilic hydroxyl groups on nanosilica surface, the durability of this property on outdoor glass was diminished rapidly after rain washing. In addition the topology of nanosilica coated glass surface plays very important roles to control an light transmittance or antireflection property. To improve these coating durability and characteristics a hydrophilic nanosilica coating on glass was prepared by coating with 1.5 wt% of nanosilica (Ludox) suspension in the presence of hydrolyzed tetraethylorthosilicate (TEOS). The optimum hydrolysis condition of TEOS in acidic or basic aqueous solution was also examined by contact angle measurement. The final transparent hydrophilic coating layer coated with nanosilica-TEOS in acidic condition (pH=4) showed much improved durability of hydrophilic surface as well as higher visible light transmittance than original uncoated glass by 2 % point.

Preparation and Characterization of transparent electrode based on polymer/metal oxide composite via electrospinning (전기 방사를 이용한 고분자/금속산화물 복합소재 기반의 투명전극 제조 및 특성 분석)

  • Kang, Hye Ju;Jeong, Hyeon Taek
    • Journal of the Korean Applied Science and Technology
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    • v.38 no.6
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    • pp.1553-1560
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    • 2021
  • We have confirmed that optimized transmittance and surface resistance by electrospinning time, also the fabricated transparent electrode composed of silver nanofiber with excellent electrical, optical and mechanical performances is showed applicability to next generation flexible displays such as solar cells, displays, and touch screens. → We have confirmed the optimized transmittance and surface resistance by electrospinning time Also the fabricated transparent electrode composed of silver nanofiber with excellent electrical, optical and mechanical performances showed applicability to next generation flexible displays such as solar cells, displays, and touch screens.