• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.50-51
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• 2009

Nitride Phosphors have recently been considered as a novel class of luminescent materials for white LEDs due to their promising luminescent properties. It is of great importance to tailor the emission color in order to meet the requirements for practical applications. The paper presents the results of tuning the emission colors of sialon phosphors through compositional tailoring.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.125-126
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• 2009

In this study, we report the room temperature synthesis and luminescence properties of white-light-emitting Rb(V,P)$O_3$. The vanadate phosphor, RbV$O_3$, was synthesized by simple mixing of $RbCO_3$ and $V_2O_5$ at room temperature in air. New direct room temperature solidstate reaction is a cost-effective method to synthesize the above luminescent materials.

• Bulletin of the Korean Chemical Society
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• v.30 no.12
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• pp.3109-3112
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• 2009

• Bulletin of the Korean Chemical Society
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• v.34 no.1
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• pp.267-270
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• 2013

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.12
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• pp.899-903
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• 2013

We investigated the luminescence properties of $Alq_3$ in the device structure of ITO/CuPc/TPD/$Alq_3$/Al. The CuPc as a hole-injection material and TPD as hole-transport material. Emission properties were measured by varying a layer thickness of CuPc (0 nm to 50 nm), which is the hole-injection layer. As a result, it was found that the hole injection occurs smoothly when the layer thickness was 20 nm among the thicknesses from 0 nm to 50 nm.

• Journal of Powder Materials
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• v.27 no.2
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• pp.154-163
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• 2020

Fluorescent nanoparticles are characterized by their unique properties such as luminescence, optical transparency, and sensitivity to various chemical environments. For example, semiconductor nanocrystals (quantum dots), which are nanophosphors doped with transition metal or rare earth ions, can be classified as fluorescent nanoparticles. Tuning their optical and physico-chemical properties can be carried out by considering and taking advantage of nanoscale effects. For instance, quantum confinement causes a much higher fluorescence with nanoparticles than with their bulk counterparts. Recently, various types of fluorescent nanoparticles have been synthesized to extend their applications to other fields. In this study, State-of-the-art fluorescent nanoparticles are reviewed with emphasis on their analytical and anti-counterfeiting applications and synthesis processes. Moreover, the fundamental principles behind the exceptional properties of fluorescent nanoparticles are discussed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.7
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• pp.600-604
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• 2005

We studied that structural and optical properties of ZnO films depend on oxygen contents. ZnO films were deposited on Si (111) substrates at room temperature by rf sputtering system and the thickness of films was 100 nm. The ZnO films were annealed in thermal furnace for 2 h at 800 and $900^{\circ}C$ in $H_2O,\;N_2$, and air ambient gases to control oxygen contents. We used AES, PL, XRD, AFM. As our result, crystal quality and luminescence improved until O/Zn is 1. However, when O/Zn ratio Is larger than 1, the structural and optical properties were getting worse.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.651-654
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• 2009

Novel compounds with rod and disc mesogens were synthesized and characterized. The molecular structures were confirmed by FT-IR, $^1H$-NMR spectroscopy and elemental analysis. The optical properties of these molecules were investigated by UV-vis absorption spectroscopy and photo-luminescence spectroscopy. We found that they are a novel series of blue light-emitting molecules. The absorption spectra peaks of these compounds varied from 336 nm-341 nm, while the maximum emissions centered form 410 nm-450 nm in chloroform solution. However, unexpectedly we could not found their biaxiality and mesomorphic properties by POM, conoscopy and DSC method.

• Bulletin of the Korean Chemical Society
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• v.34 no.9
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• pp.2597-2603
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• 2013

The reactions of hydrated $CdCl_2$, $MnCl_2$, and $NiCl_2$ with 2,2'-bipyidine-3,3',6,6'-tetracarboxylic acid ($H_4bptc$) afforded the mononuclear [$Cd^{II}(H_2bptc)(H_2O)_3]{\cdot}H_2O$ (1), linear $\{[Cd(H_2bptc)(H_2O)]{\cdot}3H_2O\}_n$ (2), 3-D heterobimetallic $[NaCd(Hbptc)(H_2O)]$ (3), layer $[Mn(H_2bptc)(H_2O)]_n$ (4) and a dinuclear compound $[Ni_2(H_2bptc)-(H_2O)_2]{\cdot}6H_2O$ (5). These compounds have been characterized by elemental analysis, IR, and their structures have been determined by X-ray crystallography. The thermal stabilities of 1-3 were measured by thermogravimetric analysis (TGA) and their solid state luminescence properties together with the free ligand $H_4bptc$ were investigated at room temperature.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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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.