• Bulletin of the Korean Chemical Society
• /
• v.21 no.10
• /
• pp.953-954
• /
• 2000

The equilibrium geometrical structures of silver atom clusters at their electronic ground states have been theo-retically determined by using the nonrelativistic semiempirical INDO/1 method. The clusters investigated are Agn, Agn+, and Agn- (n = 7 , 8, 9). In order to find the most stable structure, i.e., the global minimum in energy hypersurface, geometry optimization and energy calculation processes have been repeatedly performed for all the possible graphical models by changing the bond parameters (resonance integral values). The heptamers are pentagonal bipyramidal-Ag7(D5h), Ag7+ (D5h), Ag7- (D5h); the octamers are pentagonal bipyramidal with one atom capped-Ag8(D2d), Ag8+ (Cs), Ag8- (D2d); the nonamers are pentagonal bipyramidal with two atoms capped -Ag9(C2v), Ag9+ (C2v), Ag9- (C2v). Our structures are in good agreement with those by ab initio calculations ex-cept for the anionic Ag9- cluster. And it is noted that the INDO/1 method can accurately predict the Ag cluster geometries when a proper set of bond parameters is used.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.08a
• /
• pp.238-238
• /
• 2012

Ag (silver)의 일함수는 T-OLED (Top Emission Organic Light Emitting Diode)의 전극소자로 사용하기에는 다소 낮다는 단점이 있다(~4.3 eV). 이러한 단점을 해결하기 위한 대안으로 Ag 박막의 표면을 플라즈마 처리, UV 처리 및 열처리를 통하여 일함수를 높이는 연구가 진행 되어왔다(>5.0 eV). 하지만 현재의 대부분 연구는 후 처리된 박막의 일함수에 초점을 맞춰 연구가 진행 되어 박막의 nano-mechanical property에 대한 연구는 매우 부족하다. 따라서 본 논문에서는 AgOx 박막의 nano-mechanical property에 초점을 맞춰 분석을 실시하였다. 연구에 사용된 샘플은 Ag 박막을 유리기판 위에 rf-magnetron sputter 장치를 이용하여 100 W의 power로 150 nm 두께로 증착하였다. 증착된 Ag 박막은 $O_3$ 발생 UV 램프를 이용하여, 다양한 시간동안 UV 처리하였다(0~9분). 증착된 샘플은 Four-point probe, nanoindenter 장비를 이용하여 nano-mechanical property를 분석하였다. 실험 결과 UV 처리 시간이 0, 1분에서 면저항이 0.16, 0.50 ${\Omega}$/sq로 급격한 변화가 나타났으나, 반면 3분 이후 9분의 샘플의 경우, 0.55 ${\Omega}$/sq에서 0.24, 0.20, 0.15 ${\Omega}$/sq로 감소하여 전기적 특성변화를 볼 수 있었다. 또한 nanoindenting 결과 UV 처리한 박막의 극 표면 경도 값의 변화는 0~5분 처리한 샘플의 경우, 물리적인 경도가 증가하는 형태를 보이며 UV 처리를 5분간 했을때 7.89 GPa로 최고의 경도를 가진다. 그 이후부터는 6.97, 3.46 GPa의 결과로 박막의 경도가 감소되는 결과를 얻었다. 이러한 결과로부터 Ag 박막의 후처리에 따른 Ag 물질의 산화 및 결정상태에 따라 박막 내에 존재하는 residual stress를 분석할 수 있다.

• Journal of Fashion Business
• /
• v.21 no.6
• /
• pp.16-30
• /
• 2017

Currently, e-textile market is rapidly expanding and the emerging area of e-textiles requires electrically conductive threads for diverse applications, including wearable innovative e-textiles that can transmit/receive and display data with a variety of functions. This study introduces hybrid nano-structures which may help increase the conductivity of the textile threads for use in wearable and flexible smart apparels. For this aim, Ag was selected as a conductive material, and yarn treatment was implemented where silver nanowire (AgNW) and graphene flake (GF) hybrid structures overcome the limitations of the AgNW alone. The yarn treatment includes several treatment conditions, e.g., annealing temperature, annealing time, binder material such as polyurethane (PU), coating time, in order to search for the optimum method to form stable conductive nano-scale composite materials as thin film on the surface of textile yarns. Treatedyarns showed improved electrical resistance readings. The functionality of the spandex yarn as a stretchable conductive thread was also demonstrated. When the yarn specimens were treated with colloid of AgNW/GF, relatively good electrical conductivity value was obtained. During the extension and recovery cycles of the treated yarns, the initial resistance values did not deteriorate significantly, since the network of nanowire structure with the support of GF and polyurethane stayed flexible and stable. Through this research, it was found that when one-dimensional structure of AgNW and two-dimensional structure of GF were mixed as colloids and treated on the surface of textile yarns, flexible and stretchable electrical conductor could be formed.

• Journal of the Korean Chemical Society
• /
• v.36 no.1
• /
• pp.44-50
• /
• 1992

The ability to account for magnetic and spectra properties of complexes was investigated for the splitting of the degenerate d-orbitals and with nonaqueous solution by UV/vis-spectrophotometric method. The correlation of the magnetitude of 10Dq obtained from the spectra, the pairing energy, and the spin state of the complexes. The electrochemical behavior of complexes were investigated by the use of cyclic voltammetry in aprotic media. These reduction peak of $[(C_6H_5)3_P]_2Pd(II)(CH_3COO)_2$ and $[(C_6H_5)_3Pd]_2Pd(II)Cl_2$ were irreversible one-electron processes at peak $E_{pc1} = -1.32 V,\;E_{pc2} = -1.56 V$ and $E_{pc1} = -1.74 V,\;E_{pc2} = -1.88 V$ of these complexes vs. Ag/AgCl, but nickel complexes were not to be reducible.

• Journal of the Microelectronics and Packaging Society
• /
• v.20 no.3
• /
• pp.45-51
• /
• 2013

Thermal annealing tests were performed in an in-situ scanning electron microscope chamber at $130^{\circ}C$, $150^{\circ}C$, and $170^{\circ}C$ in order to investigate the effects of solder structure on the growth kinetics of intermetallic compound (IMC) in Cu/Sn-3.5Ag microbump. Cu/Sn-3.5Ag($6{\mu}m$) microbump with spreading solder structure showed $Cu_6Sn_5$ and $Cu_3Sn$ phase growths and then IMC phase transition stages with increasing annealing time. By the way, Cu/Sn-3.5Ag($4{\mu}m$) microbump without solder spreading, remaining solder was transformed to $Cu_6Sn_5$ right after bonding and had only a phase transition of $Cu_6Sn_5$ to $Cu_3Sn$ during annealing. Measured activation energies for the growth of the $Cu_3Sn$ phase during the annealing were 0.80 and 0.71eV for Cu/Sn-3.5Ag($6{\mu}m$) and Cu/Sn-3.5Ag($4{\mu}m$), respectively.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.671-671
• /
• 2013

실리콘 태양전지와 박막형 태양전지의 뒤를 이어, 제3세대로 분류되는 양자점 감응형 태양전지(QDSC)에 대한 연구가 활발히 진행되고 있다. 이 태양전지의 TCO로는 주로 ZnO, TiO2가 대부분 사용되고 있으며, 양자점 물질로는 CdS, CdSe, CdTe, PbS, PbSe 등의 카드뮴 및 납을 주 성분으로 하는 물질들에 대한 연구만 중점적으로 이루어지고 있는 실정이다. 이런 물질들은 현재까지 알려진 한도 내에서는 QDSC 효율 중 가장 좋은 효율을 나타내고는 있으나 이런 타입의 QDSC가 상용화된다면 환경에 노출되었을 때에 미치는 악영향이 매우 큰 중금속 물질들로 이루어져 있어, 이를 극복할 수 있는 친환경 성분의 물질에 대한 연구 또한 필요한 시점이다. 따라서 본 연구에서는 CdS를 대체할 수 있는 물질로 Ag2S를 선정, 이에 대한 연구를 진행하였다. Ag2S는 밴드갭이 1.1eV의 물질로, CdS의 2.3 eV와 비교해 상당히 작은 밴드갭을 가져 월등히 넓은 영역에서 빛을 흡수할 수 있다는 장점을 가지고 있으며, 동시에 이로 인한 전자-정공 재결합이 빨라 태양전지로 제작시에 Voc가 낮게 형성된다는 단점도 가지고 있다. 태양전지에 사용된 TCO물질은 ZnO 나노선을 사용했으며, 본 연구실에서 기존에 개발한 수열합성법을 통해 제작하였다. 이를 활용하여 최종적으로 제작한 태양전지의 효율은 CdS/ZnO QDSC가 1.2%, Ag2S/ZnO QDSC가 1.2%로 동일한 성능을 나타냈으며, CdS를 대체할 물질로 Ag2S의 가능성을 보여준 결과라 할 수 있다.

• Journal of Sensor Science and Technology
• /
• v.28 no.4
• /
• pp.266-269
• /
• 2019

In this study, $Ag_2Se$ nanoparticles were synthesized by employing the colloidal method. The synthesized $Ag_2Se$ nanocrystals were spherical in shape with a diameter of approximately 4 nm and had high crystallinity. These attributes of $Ag_2Se$ nanocrystals were determined through images obtained from a high resolution transmission electron microscope. Thin films comprising the synthesized $Ag_2Se$ nanoparticles had an optical band gap of 1.5 eV. Furthermore, fabricated NIR sensors comprising $Ag_2Se$ nanoparticles exhibited a high detectivity of $5.5{\times}10^9$ Jones (above $1{\times}10^9$) at room temperature, leading to low power consumption

• Journal of Astronomy and Space Sciences
• /
• v.13 no.1
• /
• pp.63-71
• /
• 1996

A total of 546 UBV photoelectric observations of AG Per was carried out from January to December in 1993 at Chungbuk National University Observatory. With our observations, UBV light curves were constructed, three minimum times of JDHel. 2449284.213, JDHel. 2449360.060, and JDHel. 2449363.192 were determined. The phase displacement of secondary minimum time $\delta$=-0.046 were determined and orbital eccentricity e=0.071 was calculated. Forty-five times of minimum light (including ours) were collected from the literature and plotted on O-C diagram. We analyzed these data and apsidal motion period of U=76.17 (years) was obtained. Using e and U for AG Per, the internal structure constant, log k2, was found to be -2.13.

• Microbiology and Biotechnology Letters
• /
• v.23 no.1
• /
• pp.104-109
• /
• 1995

The gene responsible for dechlorination of 4-chlorobenzoate (4CBA) was cloned in E. coli XL1-Blue from Pseudomonas sp. DJ-12. The cloned cell of E. coli Cjl had the hybrid pBluescript SK(+) plasmid, into which about 9.5 kb genomic DNA fragment of PseudOmonas sp. DJ-12 was inserted. The subclone of pCJlOl was constructed by inserting the 3.4 kb EcoRI-HindIII fragment of pCJl into the vector. Those cloned cells could be simply selected by halo formation around the colonies which was the precipitate of AgCl produced by reaction of AgNO$_{3}$ and chloride ion liberated by bacterial dechlorination of 4CBA- Such a plate assay method was standardized by the procedure that the colonies grown for 2 days on the Cl$^{-}$-free plate medium containing 1 mM 4CBA were flooded with 0.1 M AgNO$_{3}$ solution.

• Proceedings of the Optical Society of Korea Conference
• /
• 2003.02a
• /
• pp.82-83
• /
• 2003

일반적인 PDP (Plasma display panel)용 전도성 저방출(low-e) 필터는 유리 기판 위에 굴절률이 높은 금속 산화물 유전체 박막과 Ag와 같은 귀금속 박막이 번갈아 쌓인 [유전체｜금속(Ag)｜유전체]가 기본 구조인 다층 박막의 형태로 개발되어 왔다. Ag는 가시광선 영역에서 다른 금속보다 작은 흡수를 보이고 전도성이 뛰어나 전자파 차페용 필터의 전도성 박막으로 널리 쓰인다. 그리고 이러한 구조에서 가시광선의 높은 투과율을 유지하면서 유해 전자기파를 차폐할 수 있도록 충분한 전도성을 갖추기 위해서는 2층 이상의 Ag 박막이 존재하도록 설계되며 유전체 박막과 금속 박막 사이에 1∼2 nm 정도의 매우 얇은 금속 보호 층을 사용한다. (중략)