• 한국인쇄학회지
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• 제29권1호
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• pp.23-33
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• 2011

This experimental focus to characterize luminescence properties related to CNT (Carbon Nano Tube) element dispersedly implanted in ZnS-based phosphor thin film panel fabricated by a screen printing method. More specifically FE-SEM measurements, L-V(Luminescence vs. Voltage) and photo luminescence were carried out to determine an optimum value of CNT concentration and film thickness for the thin film structure of CNT-ZnS:(Cu, Al) by the screen printing method. We confirmed that an optimum value of CNT concentration in the ZnS:(Cu, Al) film panel is about 0.75 wt% resulting that the electric conductivity is 1.6 times higher than that of pure CNT sample and showing that the luminescence intensity is increasing until the optimum concentration. Clearly, CNT is presenting in the luminescence process providing a pathway for the creation of hot electron and a channel for the electron-hole recombination but overly inserted CNT may hinder to produce the hot electron for making an avalanching process. In case of the overly doped CNT 1.0 wt% in the ZnS-based phosphor, the luminescence intensity is decreasing although the electric conductivity is exponentially increasing. Based on these results, we realized that hot electron occurred by the external electric field or exciton arose by the external photon source are reduced dramatically over the critical value of CNT concentration because CNT element provide various isolated residues in the composites of ZnS based phosphor rather than pathway or channel for the D-A(Donnor to Acceptor) pair transition or the radiative recombination of electron-hole.

• Bulletin of the Korean Chemical Society
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• 제31권8호
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• pp.2151-2157
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• 2010

Spectroscopic and quantum mechanical studies of the Et3PAuCl complex were performed to characterize the effect of aurophilicity on the optical properties. When excited with UV light at low temperature, the crystalline complex produced a deep luminescence in both the blue (high-energy) and red (low-energy) regions of the spectrum. The intensity of the low-energy luminescence was markedly reduced in the powdered state and quenched in the solution state. Time-dependent density functional theory (TD-DFT) calculations on electronic structures of both the ground and excited states of aggregates $[Et_3PAuCl]_n$ (n = 1 - 3) indicated that the low-energy luminescence was attributable to Au-centered transitions, which are significantly affected by aurophilic interactions. By contrast, the high-energy luminescence appeared to be independent of the state of the complex and was strongly associated with the charge transfer from Cl to Au.

• 방사성폐기물학회지
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• 제18권4호
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• pp.497-508
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• 2020

In the geochemical field, the chemical speciation of hexavalent uranium (U(VI)) has been widely investigated by performing measurements to determine its luminescence properties, namely the excitation, emission, and lifetime. Of these properties, the excitation has been relatively overlooked in most time-resolved laser fluorescence spectroscopy (TRLFS) studies. In this study, TRLFS and continuous-wave excitation-emission matrix spectroscopy are adopted to characterize the excitation properties of U(VI) surface species that interact with amorphous silica. The luminescence spectra of U(VI) measured from a silica suspension and silica sediment showed very similar spectral shapes with similar lifetime values. In contrast, the excitation spectra of U(VI) measured from these samples were significantly different. The results show that distinctive excitation maxima appeared at approximately 220 and 280 nm for the silica suspension and silica sediment, respectively.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.170.2-170.2
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• 2015

Enormous interest in trivalent rare-earth (RE) ions activated luminescent materials has been gaining owing to their promising applications in bio-imaging, solar cells, white light-emitting diodes and field-emission displays. Among these trivalent RE ions, dysprosium (Dy3+) was widely investigated due to its unique photoluminescence (PL) emissions. A series of Dy3+-activated CaWO4 phosphors were prepared by a facile high-temperature solid-state reaction method. The X-ray diffraction, PL spectra, cathodoluminescence (CL) spectra as well as PL decay curves were used to characterize the prepared samples. Under ultraviolet light excitation, the characteristic emissions of Dy3+ ions were observed in all the obtained phosphors. Furthermore, the PL emission intensity increased gradually with the increment of Dy3+ ion concentration, reaching its maximum value at an optimized Dy3+ ion concentration. Additionally, color-tunable emissions were obtained in Dy3+-activated CaWO4 system by adjusting the Dy3+ ion concentration and excitation wavelength. Ultimately, strong CL properties were observed in Dy3+-activted CaWO4 phosphors. These results suggested that the Dy3+-activted CaWO4 phosphors may have potential applications in the field of miniature color displays.

• 반도체디스플레이기술학회지
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• 제7권4호
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• pp.19-22
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• 2008

Thin film has been an increasing important subject of intensive research, owing to the fact that these films possess desirable optical, electrical and electrochemical properties for uses in many semi-conducting nano-crystal applications, such as light-emitting diodes, lasers and solar cell applications. Here, ZnSe thin films were deposited by electrochemical method for the applications of light emitting diode. Electrochemical deposition of ZnSe thin film is not easy, because of the high difference of reduction potential between zinc ion and selenium acid. In order to handle the band gap of ZnSe crystal thin films easily, electrochemical methods are promising to manufacture these films economically. Therefore we have investigated the present study to characterize zinc selenide thin films deposited on ITO glass plates electrochemically. The luminescent properties of ZnSe films have been evaluated by UV-Vis spectrometer and luminescence spectrometer. And the morphology of the film surface has been discussed qualitatively from SEM images.

• 한국해양생명과학회지
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• 제7권2호
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• pp.74-85
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• 2022

Organisms constituting a large proportion of marine ecosystems, ranging from bacteria to fish, exhibit fluorescence and bioluminescence. A variety of marine organisms utilize these biochemically generated light sources for feeding, reproduction, communication, and defense. Since the discovery of green fluorescent protein and the luciferin-luciferase system more than a century ago, numerous studies have been conducted to characterize their function and regulatory mechanism. The unique properties of fluorescent and bioluminescent proteins offer great potential for their use in a broad range of applications. This short review briefly describes the functions and characteristics of fluorescent and bioluminescent proteins, in addition to summarizing the recent status of their applications.

• 분석과학
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• 제17권2호
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• pp.163-172
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• 2004

토양 풀빅산 (FA)의 분자량 크기 분포와 분자량별 형광특성을 겔 여과 크로마토그래피(GFC)와 형광분석시스템을 사용하여 분석하였다. 본 연구에서는 제주 지역 토양에서 추출한 풀빅산을 세 개의 분자량 영역으로 분리하였고, 분자량별 풀빅산의 excitation, emission, synchronous 형광특성을 비교 분석하였다. 토양 풀빅산의 분자량 분리를 위한 GFC 시스템은 아세톤과 덱스트란 블루 및 폴리에틸렌 글리콜 표준분자를 사용하여 교정하였다. 분자량 분리 시스템의 틈새부피는 130 mL이고, total permeation volume은 404 mL을 나타냈다. 이 시스템을 풀빅산의 분자량 분리에 적용한 결과, 토양 풀빅산은 190~8,900 Da의 분자량 분포를 나타냈으며 피크점에서의 분자량은 930 Da을 나타냈다. 분자량별 구조 차이를 나타내는 synchronous 형광피크의 상대비 ($I_{498nm}/I_{390nm}$)는 분자량이 클수록 증가하였다. 이와 같은 결과는 고 분자량의 풀빅산이 저 분자량의 풀빅산에 비해 ${\pi}$-결합으로 연결된 방향족 고리와 다양한 치환기가 결합된 좀더 복잡한 분자 구조임을 제시한다.

• 폴리머
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• 제32권4호
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• pp.305-312
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• 2008

A novel TPC-PEG-TPC with active end-groups was obtained from the end-groups of polyethylene glycol (PEG) modified by terephthaloyl chloride (TPC). These active end-groups can link up with a rare earth ion, which is a luminescent center of a rare earth fluorescent complex. Complexes of Eu-PEG with novel ligands (TPC-PEG-PTC) were synthesized by the coordination of the active reactant (as the first ligand) and phenanthroline (as the second ligand) with $Eu^{3+}$.IR, $^1H$-NMR, element analysis, DSC, WAXD, fluorescent spectroscopy, TGA, and SEM were used to characterize the structure and properties of these complexes. The results showed that this type of complex is a heat storage material with the phase change character of polyethylene glycol (PEG) and the luminescent properties of europium. There was no thermal decomposition of the complex of Eu-PEG until $300^{\circ}C$. SEM showed that the complex of Eu-PEG can be dispersed in PE.

• 한국광물학회지
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• 제17권2호
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• pp.123-133
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• 2004

포항지역 제3기 해성퇴적층에서 산출되는 탄산염광물의 특성을 밝히기 위하여 음극선 발광현미경 관찰과 화학분석을 실시하였다. 발광현미경은 보통의 편광 현미경으로는 관찰할 수 없는 정보를 제공해 준다. 사암의 탄산염 교질물 내에서, 편광현미경하에서는 나타나지 않는 유공충의 형태와 마름모꼴로 자란 돌로마이트 형태들이 음금선 발광현미경하에서는 명확히 나타난다. 화학분석 결과, 발광은 탄산염 광물 내의 망간 성분과 칠 성분에 의해서 나타난다. 그러나 돌로마이트 내의 철성분이 10,000 ppm을 넘게 되면 발광은 사라진다. 산출되는 돌로마이트는 칼슘 성분이 많은 것이 특징이며, $60～70^{\circ}C$의 초기 속성작용 단계에서 생성된 것으로 생각된다.

• 한국세라믹학회지
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• 제55권1호
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• pp.55-60
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• 2018

In this study, quantum dots composed of $Mn^{2+}$ doped ZnS core and ZnS shell were synthesized using MPA precursor at room temperature. The ZnS: Mn/ZnS quantum dots were prepared by varying the content of MPA in the synthesis of ZnS shells. XRD, Photo-Luminescence (PL), XPS and TEM were used to characterize the properties of the ZnS: Mn/ZnS quantum dots. As a result of PL measurement using UV excitation light at 365 nm, the PL intensity was found to greatly increase when MPA was added at 15 ml, compared to the case with no MPA; the PL peaks shifted from 603 nm to 598 nm. A UV sensor was fabricated by using a sputtering process to form a Pt pattern and placing a QD on the Pt pattern. To verify the characteristics of the sensor, we measured the electrical properties via irradiation with UV, Red, Green, and Blue light. As a result, there were no reactions for the R, G, and B light, but an energy of 3.39 eV was produced with UV light irradiation. For the sensor using ZnS: Mn/ZnS quantum dots, the maximum current (A) value decreased from $4.00{\times}10^{-11}$ A to $2.62{\times}10^{-12}$ A with increasing of the MPA content. As the MPA content increases, the PL intensity improves but the electrical current value dropped because of the electron confinement effect of the core-shell.