• 한국전기전자재료학회논문지
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• 제37권3호
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• pp.274-279
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• 2024

Eu³⁺-doped BaZrO₃ (BaZrO₃:Eu³⁺) phosphor powders were prepared using a solid-state reaction by changing the molar concentration of Eu³⁺ within the range of 0.5 to 30 mol%. Irrespective of the molar concentration of Eu³⁺ ions, the crystal structures of all the phosphors were cubic. The excitation spectra of BaZrO₃:Eu³⁺ phosphors consisted of an intense broad band centered at 277 nm in the range of 230~320 nm. The emission spectra were composed of a dominant orange band at 595 nm arising from the ⁵D₀→⁷F₁ magnetic dipole transition of Eu³⁺ and two weak emission bands centered at 574 and 615 nm, respectively. As the concentration of Eu³⁺ increased from 0.5 to 10 mol%, the intensities of all the emission bands gradually increased, approached maxima at 10 mol% of Eu³⁺ ions, and then showed a decreasing tendency with further increase in the Eu³⁺ ions due to the concentration quenching. The critical distance between neighboring Eu³⁺ ions for concentration quenching was calculated to be 11.21 Å, indicating that dipole-dipole interaction was the main mechanism of concentration quenching of BaZrO₃:Eu³⁺ phosphors. The results suggest that the orange emission intensity can be modulated by doping the appropriate concentration of Eu³⁺ ions.

• 한국세라믹학회지
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• 제48권1호
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• pp.86-93
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• 2011

Transparent plasma display can be realized by developing the synthetic chemistry of appropriate nanophosphors and generating nanophosphor-based transparent luminescent layers. For this goal, red-emitting $Y(V_{0.5},\;P_{0.5})O_4$:Eu nanophosphors were synthesized by a facile hydrothermal route at $200^{\circ}C$ for 48 h and the resulting nanophosphors were subsequently annealed at $800^{\circ}C$ at an ambient atmosphere. The crystallographic structure, morphology, and emission property of the as-synthesized and annealed nanophosphors were compared. Choosing 2-methoxyethanol as a dispersion medium and applying a standard sonication, well-dispersed nanophosphor solutions could be prepared. Using these dispersions, visible transparent nanophosphor layers were spin-deposited on glass substrates. By combining $Y(V_{0.5},\;P_{0.5})O_4$:Eu nanophosphor layer/glass substrate as a rear plate with a front plate used in a conventional plasma display panels (PDPs), mini-sized transparent red-emitting PDPs were constructed. Transmittance and luminance properties of two transparent test panels using as-synthesized versus $800^{\circ}C$-annealed nanophosphors were characterized and compared.

• 센서학회지
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• 제8권1호
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• pp.10-15
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• 1999

ZnS 형광체와 BST 강유전체 박막을 절연층으로 사용한 백색방출 전계발광소자를 제작하였다. BST 박막의 제조조건으로 target의 조성비가 $Ba_{0.5}Sr_{0.5}TiO_3$이며, 기판온도가 $400^{\circ}C$, 분위기압이 30 mTorr, A:$O_2$의 비가 9:1일때 유전율이 1 kHz의 주파수에서 209를 나타내었다. 형광층으로 ZnS:Mn, ZnS:Tb 및 ZnS:Ag를 사용하였으며, 활성제 각각의 첨가량은 0.8, 0.8 및 1 wt%로 하였다. 형광층 전체의 두께가 500 nm로 하고 하부 절연층을 200 nm, 상부절연층을 400 nm로 증착하였을 때, 박막 전계발광소자의 발광문턱전압은 약 95 V 였고, 최고휘도는 150 V에서 약 $3000\;cd/m^2$이었다. 발광스펙트럼를 관찰한 결과 청색영역(450 nm), 녹색영역(550 nm) 그리고 적색영역(600 nm)의 파장에서 각각의 피이크가 나타나는 것을 관찰하였다.

• 폴리머
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• 제37권1호
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• pp.94-99
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• 2013

폴리디아세틸렌(polydiacetylene, PDA)은 자기조립된 디아세틸렌(diacetylene) 단량체의 광중합에 의해 만들어진다. 디아세틸렌 단량체들이 조직적으로 배열되면 254 nm의 자외선 노광에 의해 1,4-첨가 중합이 일어나 고분자 주사슬에 이중결합과 삼중결합이 교대로 존재하는 폴리디아세틸렌이 만들어진다. 폴리디아세틸렌 수용액은 일반적으로 약 640 nm에서 최대흡수파장을 지니는 청색을 띠게 되며 여기에 온도나 pH의 변화, 다른 물질의 결합 등 외부 자극에 의해 약 550 nm의 최대 흡수 파장을 띠는 적색으로 색 전이가 일어나게 된다. 본 연구에서, 우리는 고체상 펩티드 합성을 이용하여 PCDA(10,12-pentacosadyinoic acid) 리포좀의 표면에 양이온성 올리고펩티드를 도입하였다. 또한 다양한 몰 비율로 리포좀 수용액을 제조하여 동물 세포에 트랜스펙션한 결과, 향상된 유전자 전달 효율과 낮은 독성을 보이는 것을 확인하였고, PCDA의 특성을 이용하여 세포에 처리 후 세포 관련 비표지 형광을 관찰하였다.

• 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.

• 한국버섯학회지
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• 제15권4호
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• pp.259-263
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• 2017

표고 '농진고'를 LED 혼합광에 따른 갓의 색차 및 경도차를 확인한 결과 갓의 명도값은 형광등 처리구 대비 LED혼합광 처리구 모두 낮아지는 결과를 나타내었다. 적색도는 형광등 처리구에 비해 처리구 모두 높아졌고, 황색도는 낮아지는 결과를 보였다. 광원별 자실체의 생육특성을 조사한 결과 형광등 대조구 대비 처리구 모두에서 갓직경이 컸으며, 자실체들에 대한 균일도는 형광등 처리구 대비 LED를 사용하였을 경우 낮은 값을 나타내어 형광등을 처리하는 것보다 균일도가 있는 것으로 나타났다. 대직경은 처리구간 큰 차이를 보이지는 않았으나 White Green LED에서 다른 처리구보다 높은 것으로 조사되었고, 대길이는 형광등 처리구보다 LED처리구 모두에서 다소 높게 조사되었다. 갓직경과 대길이의 비를 조사한 결과 White Green LED을 제외한 White LED와 White Blue LED에서 형광등 처리구 대비 높은 값을 나타내어 대길이에 비해 갓의 직경이 길어지는 것을 확인할 수 있었다. 자실체 물추출물의 항산화능을 확인한 결과 형광등 처리구에서 가장 높은 항산화능을 확인할 수 있었고 LED 처리는 White LED처리에서 가장 큰 항산화능을 확인하였고 White Green LED, White Blue LED간에는 유의한 차이를 보이지 않았으나 LED처리는 Vitamin C 보다 높은 항산화능을 나타내었다. 위의 결과를 통해 White LED와 White Blue 처리가 표고버섯 자실체의 생육 및 항산화능에 영향을 미치는 광원임을 확인할 수 있었다.

• 한국재료학회지
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• 제26권9호
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• pp.504-511
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• 2016

To prepare $Mn^{4+}$-activated $K_2TiF_6$ phosphor, a precipitation method without using hydrofluoric acid (HF) was designed. In the synthetic reaction, to prevent the decomposition of $K_2MnF_6$, which is used as a source of $Mn^{4+}$ activator, $NH_5F_2$ solution was adopted in place of the HF solution. Single phase $K_2TiF_6$:$Mn^{4+}$ phosphors were successfully synthesized through the designed reaction at room temperature. To acquire high luminance of the phosphor, the reaction conditions such as the type and concentration of the reactants were optimized. Also, the optimum content of $Mn^{4+}$ activator was evaluator based on the emission intensity. Photoluminescence properties such as excitation and emission spectrum, decay curve, and temperature dependence of PL intensity were investigated. In order to examine the applicability of this material to a white LED, the electroluminescence property of a pc-WLED fabricated by combining the $K_2TiF_6$:$Mn^{4+}$ phosphor with a 450 nm blue-LED chip was measured.

• 한국세라믹학회지
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• 제47권2호
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• pp.122-126
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• 2010

In this article photoluminescence of the $Al_2O_3:xCr_2O_3$ solid solutions prepared by solid state reaction method are represented. The effect of $Cr_2O_3$-activator concentration and heat treatment time on the PL characteristics have been discussed in conjunction with microstructure of phosphor samples. The $Al_2O_3:xCr_2O_3$ phosphors show the highest PL intensity at x=0.003 mole when the samples are reacted at $1600^{\circ}C$ for 5 h. The PL emission and absorption spectra show the maximum peaks at 698 nm and at 398 nm respectively. The CIE color coordinate is (x=0.646, y=0.316) at 0.003 mole $Cr_2O_3$, which value is very close to the NTSC coordinate of red color. This characteristic feature of $Al_2O_3:xCr_2O_3$ has been applied for an additive to improve the color characteristic of other red phosphor $LiEuW_2O_8$ which has a relatively poor color purity with an emission peak centered at 615 nm and with a CIE coordinate (x=0.530, y=0.280). The $Al_2O_3:0.003Cr_2O_3$ phosphor has been mixed with the $LiEuW_2O_8$ phosphor powder and the PL characteristics and CIE color coordinates are characterized. The $Al_2O_3:xCr_2O_3$ phosphor was found effective for improving the CRI (color rendering index) of $LiEuW_2O_8$ phosphor.

• 한국전기전자재료학회논문지
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• 제30권1호
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• pp.48-53
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• 2017

We report the studies on the red organic phosphor by using perylene bisimide derivatives. Even though perylene bisimide derivatives have excellent thermal stability and luminous efficiency, they have low solubility in organic solvents. In this research, modified perylene bisimide derivative, N,N'-Bis(4-bromo-2, 6-diisopropylphenyl)-1, 6, 7, 12-tetraphenoxyperylene-3, 4, 9, 10-tetracarboxyl bisimide (1C), has been prepared by the reaction of phenol with N,N'-Bis(4-bromo-2, 6-diisopropylphenyl)-1, 6, 7, 12-tetrachloroperylene-3, 4, 9, 10-tetracarboxyl bisimide (1B) in presence of DMF, at $70^{\circ}C$. The synthesized (1C) was characterized by using $^1H-NMR$, FT-IR, UV/V is spectroscopy, and TGA. The absorbtion and emission of (1C) was shown at 576 nm and 610 nm in UV/V is spectrum. In TGA thermogram, (1C) showed good thermal stability without significant weight loss to $220^{\circ}C$. And in the solubility analysis, (1C) with phenoxy group showed the good solubility in general organic solvents. The blended films of (1C) with PMMA (polymethyl methacrylate) at different weight % concentration such as 10, 5, 1 weight % have been prepared. The blended film was shown at 616 nm when monitored at 450 nm in PL emission spectra.

• 한국산림과학회지
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• 제95권6호
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• pp.716-722
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• 2006

Eucalyptus pellita 기내줄기를 재료로 광질에 따른 생육 특성을 조사하였다. 전반적으로 줄기의 생장은 광질보다는 환기처리가 더 주요한 요인으로 나타났다. 특히 환기처리 한 청색광(blue LED) 하에서 묘고, 잎수, 절간수 및 액아수가 양호하였고, 잎에 캘러스가 형성되지 않았다. 식물체의 충실정도를 나타내는 건물율 역시 환기처리 하에서 높게 나타났으며, 청색광 하에서 가장 높은 건물율을 나타냈다. 광질별 총엽록소 함량은 형광등과 혼합광 R5B5(50% red LED + 50% blue LED)에서 $24.5{\mu}g/g$ 및 $20.1{\mu}g/g$으로 가장 높게 나타났다. 광합성에 관여하는 카로티노이드 함량 역시 적색광(red LED)을 제외한 모든 광질에서 환기 처리 시 양호하게 나타났다. 결론적으로 E. pellita의 기내 줄기생장은 환기처리가 중요하고, 총 카로티노이드 함량을 기준으로 볼 때 혼합광 R5B5에서 건전한 줄기생장이 가능한 것으로 나타났다.