• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.233-233
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• 2006

[ $Y_{2}O_{2}S:Eu$ ], a red phosphor, coated with silica nanoparticles or nanocomposites composed of silica nanoparticles and polymeric materials such as PMMA and PVP was prepared via sol-gel process. Samples were prepared from four different methods coded P1, P2, P3, and P4. P1 includes a conventional sol-gel process and a dip-coating method while P2 has the same procedure with P1 except that nanocomposites containing both silica nanoparticles and polymer prepared by sol-gel process were used as coating materials. In P3 method, phosphors were dispersed in a solution containing silica precursor, i.e., TEOS and then polymerization was performed to coat onto the phosphors surface while P4 followed the same procedure with P3 except that a solution containing both TEOS and organic monomer were used in preparing coating materials. Among various coating methods examined in this study, uniform coating of phosphor could be achieved by using method P4, i.e., phosphor surface coating in a solution containing hydrophobic monomer and TEOS. Furthermore, $Y_{2}O_{2}S:Eu$ red phosphor coated with nanocomposite composed of PMMA matrix and silica nanoparticles exhibited enhanced PL intensity and long-term stability.

• 문화기술의 융합
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• 제9권5호
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• pp.523-528
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• 2023

금속염 수용액과 고분자 매개체를 출발물질로 사용한 액상합성법으로 적색 파장을 방출하는 형광체를 합성하여, 태양전지 성능향상을 위한 소재로서의 적용 가능성을 검토하였다. Ca, Zn, Al, Eu 등 금속의 질산염을 사용하여 수용액을 제조하고 이것을 식물성 고분자인 전분에 함침시킨 전구체를 소결하여 CaZnAlO:Eu 형광체 분말을 합성하였다. 합성한 CaZnAlO:Eu 형광체 분말의 표면구조 및 성분분석을 주사전자현미경(SEM)과 에너지분산형 X-선분광법(EDS)으로 분석하였다. PL측정 결과 650-780nm의 근적외선영역의 발광파장을 가지는 적색형광체가 성공적으로 합성되었다. XRD 분석결과 단일상을 가진 순수한 CZA:Eu³⁺ 형광체가 합성된 것을 확인하였다. SEM, EDS 분석 결과 합성한 Ca₁₄Zn₆Al_9.93O₃₅:Eu³⁺_0.07 형광체 분말의 입도가 균일하며, 부활제로 사용한 Eu 이온이 존재하고 있는 것을 알 수 있다. 합성된 CZA:Eu³⁺ 형광체는 자외선이나 가시광선을 근적외선영역의 파장으로 하향변환하여 태양전지의 광 흡수효율을 높일 수 있는 소재로 활용될 수 있다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.415.2-415.2
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• 2014

Cost-effective, robust devices for solid-state lighting industry that converts electricity to light revolutionize the current lighting industry. Phosphor materials used in these devices should be synthesized in a low-cost and effective method for use in WLEDs. In this presentation, the synthesis of Eu3+ ions doped BaMoO4 phosphor samples by a facile synthesis process for red component of WLEDs will be shown. The tetragonal phase of the host lattice was substantiated by the X-ray diffraction patterns. The morphological studies were carried out by using a field-emission scanning electron microscope and transmission electron microscope. These confirmed the formation of a shuttle like particles with perpendicular protrusions in the middle of the particle. The photoluminescence (PL) properties exhibited good emission with a high asymmetry ratio when excited with ultraviolet B wavelengths (~ 280-315 nm). The cathodoluminescence (CL) spectra showed similar results to the PL spectra, indicating the rich red emission. The results suggest that this phosphor is a good material as red region component in the development of tri-band UV excitation based WLEDs.

• Transactions on Electrical and Electronic Materials
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• 제9권2호
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• pp.57-61
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• 2008

The $(Y,Gd)_2O_3$:Eu phosphors were synthesized using the impregnation method in order to improve the performance of red-emitting phosphors for plasma display panels. $(Y,Gd)_2O_3$:Eu phosphors, with a particle size ranging from 150 and 200 nm, exhibited a strong red emission at around 615 nm. The emission intensity and particle size of the powders were controlled by adjusting the sintering temperature and raw material composition. The resulting particle size was very uniform and photoluminescence (PL) characteristic was excellent, being about twice that of commercial red phosphor.

• 한국재료학회지
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• 제27권6호
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• pp.312-317
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• 2017

In the construction of a white LED, the region of the red emission is a very important factor. Red light emitting materials play an important role in improving the color rendering index of commercial lighting. These materials also increase the color gamut of display products. Therefore, the development of novel phosphors with red emission and the study of color tuning are actively underway to improve product quality. In the present study, heuristic algorithms were used to search for phosphors capable of increasing the color rendering index and color gamut. Using a heuristic algorithm, the phosphors that were identified were $SrGe_4O_9:Mn^{4+}$ and $BaGe_4O_9:Mn^{4+}$. Emission spectra study confirmed that these phosphors emit light in the deep red wavelength region, which can fulfill the requirement for the improvement in color rendering index and color gamut for a white LED.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.594-597
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• 1999

The new green and red phosphors for PDP application activated by T $b^{3+}$ and E $u^{3+}$ were synthesized, and their photoluminance properties were investigated. It was found that the brightness of $Al_3$Gd $B_4$ $O_{12}$ :T $b^{3+}$ green phosphor under 147nm VUV irradiation was higher than that of commercial Z $n_2$ $SiO_4$:M $n^{2+}$ phosphor. But the emitting intensity of A1$_3$Gd $B_4$ $O^{12}$ :E $u^{3+}$ red phosphor was inferior to the commercial (Y,Gd)B $O_3$:E $u^{3+}$. $Al_3$Gd $B_4$ $O_{12}$ Phosphor had a strong excitation band at 160nm associated with the host absorption, and also the photoluminance excitation intensity of $Al_3$Gd $B_4$ $O_{12}$ :T $b^{3+}$ was higher than that of Z $n_2$ $SiO_4$:M $n^{2+}$, but the intensity of $Al_3$Gd $B_4$ $O_{12}$ :E $u^{3+}$ phosphor was smaller than (Y,Gd)B $O_3$:E $u^{3+}$ phosphor In the VUV range. C $e^{3+}$ co-doping in A1$_3$Gd $B_4$ $O^{12}$ :E $u^{3+}$ and substitution of $Al^{3+}$ by G $a^{3+}$ A1$_3$Gd $B_4$ $O^{12}$ :E $u^{3+}$ phosphor were tried, but they did not improved the optical property .d the optical property .ty .

• 한국재료학회지
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• 제29권2호
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• pp.116-120
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• 2019

We prepared $Y_3Al_5O_{12};Ce^{3+},Pr3^{+}$ transparent ceramic phosphor using a solid state reaction method. By XRD pattern analysis and SEM measurement, our phosphors reveal an Ia-3d(230) space group of cubic structure, and the transparent ceramic phosphor has a polycrystal state with some internal cracks and pores. In the Raman scattering measurement with an increasing temperature, lattice vibrations of the transparent ceramic phosphor decrease due to its more perfect crystal structure and symmetry. Thus, low phonon generation is possible at high temperature. Optical properties of the transparent ceramic phosphor have broader excitation spectra due to a large internal reflection. There is a wide emission band from the green to yellow region, and the red color emission between 610 nm and 640 nm is also observed. The red-yellow phosphor optical characteristics enable a high Color Rendering Index (CRI) in combination with blue emitting LED or LD. Due to its good thermal properties of low phonon generation at high temperature and a wide emission range for high CRI characteristics, the transparent ceramic phosphor is shown to be a good candidate for high power solid state white lighting.

• 한국재료학회지
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• 제19권3호
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• pp.163-168
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• 2009

$Eu^{3+}$-doped $Y_2O_3$ red phosphor was synthesized in a flux method using the chemicals $Y_2O_3,\;Eu_2O_3,\;H_3BO_3$ and $BaCl_2{\cdot}2H_2O$. The effect of a flux addition on the preparation of $Y_2O_3:Eu_{3+}$ red phosphor used as a cold cathode fluorescence lamp was investigated. $H_3BO_3$ and $BaCl_2{\cdot}2H_2O$ fluxes were used due to their different melting points. The crystallinity, thermal properties, morphology, and emission characteristics were measured using XRD, TG-DTA, SEM, and a photo-excited spectrometer. Under UV excitation of 254 nm, $Eu_2O_3$ 3.7 mol% doped $Y_2O_3$ exhibited a strong narrow-band red emission, peaking at 612 nm. From this result, the phosphor synthesized by firing $Y_2O_3$ with 3.7 mol% of $Eu_2O_3$, 0.25 mol% of $H_3BO_3$ and 0.5 mol% of $BaCl_2{\cdot}2H_2O$ fluxes at $1400^{\circ}C$ for 2 hours had a larger particle size of $4{\mu}m$ on average compared to the phosphor of the $H_3BO_3$ flux alone. In addition, a phosphor synthesized by the two fluxes together had a rounder corner shape, which led to the maximum emission intensity.

• 한국결정성장학회지
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• 제33권1호
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• pp.1-16
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• 2023

LED용 비희토류 기반 strontium-aluminate 계 적색 발광 형광체를 고상반응법으로 합성하였고, 합성온도 및 Mn⁴⁺ 활성제 첨가량이 형광체의 발광특성에 미치는 영향에 대하여 조사하였다. 합성된 SrAl₂O₄:Mn⁴⁺ 형광체는 330 및 460 nm 근처 파장에서 피크가 나타나는 근자외선 및 청색 영역의 광대역 흡광 특성과 644, 658, 및 673 nm 근처의 세 개의 피크로 이루어진 삼중밴드 형태의 deep red 발광 특성을 나타내었다. 합성온도 1600℃, 0.5 mol% Mn⁴⁺ 이온 첨가량에서 합성된 SrAl₂O₄:Mn⁴⁺ 형광체가 가장 우수한 발광 특성을 나타내었고, 0.7 mol% 이상의 첨가량에서는 농도소광이 관찰되었다. FE-SEM 및 DLS 입도크기분포 분석 결과 합성된 SrAl₂O₄:Mn⁴⁺ 형광체 2~6.4 ㎛의 입도 분포 및 불규칙한 구형을 나타내며 약 4 ㎛의 평균 입자 크기를 갖는 것으로 조사되었다.

• 조명전기설비학회논문지
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• 제21권9호
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• pp.12-17
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• 2007

The dynamic false contour noise was analyzed with consideration for the phosphor decay time of an ac PDP by computer simulation based on the measurement of the 1/10 phosphor decay times of the primary colors red, green and blue at the main wavelengths of each phosphor. The noise level of dynamic false contour is strongly dependent on phosphor decay time. The noise level decreases incrementally with the phosphor decay time, whereas the noise width increases. The moving velocity of an object does not affect the noise level. The entire experiment was performed under the condition of 8 subfields ADS driving scheme, 2.5[${\mu}sec$] scan speed, and 5[${\mu}sec$] sustain period with VGA grade panel.