• 한국분말재료학회지
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• 제24권6호
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• pp.457-463
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• 2017

Nanosized $Gd_2O_3:Eu^{3+}$ red phosphor is prepared using a template method from metal salt impregnated into a crystalline cellulose and is dispersed using a bead mill wet process. The driving force of the surface coating between $Gd_2O_3:Eu^{3+}$ and mica is induced by the Coulomb force. The red phosphor nanosol is effectively coated on mica flakes by the electrostatic interaction between positively charged $Gd_2O_3:Eu^{3+}$ and negatively charged mica above pH 6. To prepare $Gd_2O_3:Eu^{3+}$-coated mica ($Gd_2O_3:Eu/mica$), the coating conditions are optimized, including the stirring temperature, pH, calcination temperature, and coating amount (wt%) of $Gd_2O_3:Eu^{3+}$. In spite of the low luminescence of the $Gd_2O_3:Eu/mica$, the luminescent property is recovered after calcination above $600^{\circ}C$ and is enhanced by increasing the $Gd_2O_3:Eu^{3+}$ coating amount. The $Gd_2O_3:Eu/mica$ is characterized using X-ray diffraction, field emission scanning electron microscopy, zeta potential measurements, and fluorescence spectrometer analysis.

• 공업화학
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• 제18권6호
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• pp.587-591
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• 2007

본 연구는 유기발광디바이스용 적색형광물질인 6-(10-알킬페노티아진-3-비닐렌)-2-메틸-4-디시아노메틸렌-4H-피란 합성에 관한 것으로서 유도체들은 Knoevenagel 축합반응에 의하여 합성되었다. 이들은 전자공여성의 6-(10-알킬페노티아진-3-비닐렌)기와 전자흡인성의 2-메틸-4-디시아노메틸렌-4H-피란의 공액구조를 가지고 있다. 합성한 물질은 각각 FT-IR, $^1H-NMR$ 등을 통하여 그의 구조적 특성을 확인하였고, 융점, 수득율을 통하여 열적 안정성, 반응성 등을 확인하였으며, UV-visible과 PL분석으로부터 이 형광재료들의 광학적 특성을 확인하였다.

• 한국전기전자재료학회논문지
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• 제25권3호
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• pp.193-197
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• 2012

$Gd_{1-x}VO_4:{Eu_x}^{3+}$ red phosphors were synthesized with changing the concentration of $Eu^{3+}$ ion by using a solid-state reaction method. The crystal structure, surface morphology, and photoluminescence and photoluminescence excitation properties of the red phosphors were measured by using X-ray diffractometer, field emission-scanning electron microscopy, and florescence spectrometer, respectively. The XRD results showed that the main peak of all the phosphor powders occurs at (200) plane. As for the photoluminescence properties, the maximum excitation spectrum occurred at 306 nm due to the charge transfer band from ${VO_4}^{3-}$ to $Eu^{3+}$ ions and the maximum emission spectrum was the red luminescence peaking at 619 nm when the concentration of $Eu^{3+}$ ion was 0.10 mol.

• 한국광학회지
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• 제7권2호
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• pp.120-128
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• 1996

1at.% Er$^{3+}$ :LaF$_{3}$와 1at.%Er$^{3+}$ :YAlO$_{3}$ 결정체에 대해 780-820nm에서 펌핑하여 적색, 녹색 및 청색이 상방전환 형광 발생을 상온과 14K에서 연구하였다. 두 재료에 대해 Er$^{3+}$ 이온의 $^{4}$I$_{9}$ 2/준위를 펌핑하기 위해 연속 출력의 티나튬 사파이어 레이저를 사용하였다. 이러한 $^{4}$F$_{9}$ 2/, $^{4}$S$_{3}$2/, $^{2}$P$_{3}$2/로부터 상방전환의 형광 발생 과정이 다단계 흡수와 교차 완화의 에너지 전달에 의한 것임을 스펙트럼의 분석을 통행 밝혀내었다.

• Journal of Plant Biotechnology
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• 제35권3호
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• pp.215-221
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• 2008

소멸위기 식물인 덩굴용담을 재료로 기내 생장 및 발근에 미치는 광질 및 환기효과를 조사하였다. 무처리 혹은 환기가 가능한 2종의 배양용기에 신초를 배양한 다음 5가지의 서로 다른 광질 1) 형광등, 2) 100% 적색광(R), 3) 70% 적색광+30% 청색광(R7B3), 4) 50% 적색광+50% 청색광(R5B5), 및 5) 100% 청색광 하에서 4주간 배양하였다. 실험을 통해 얻은 주요 결과는 다음과 같다. 1. 발근율은 형광등과 적색광에서 $80{\sim}100%$로 높았고, 특히 환기 처리시 100%의 발근율을 보였다. 광질별로는 적색광이 절간신장을 촉진시키고 청색광은 억제하는 경향이었다. 전반적으로 환기처리 시 진녹색의 큰 잎으로 자랐고, 액아의 발달을 억제하여 1-2개의 우세줄기로 생장하였다. 2. 식물체의 총 생체중은 적색광과 청색광이 7:3의 비율로 혼합된 혼합광 R7B3에서 가장 높았고, 특히 환기처리 시 식물체 당 257.7 mg으로 가장 높았다. 식물체의 충실을 나타내는 건물율(dry matter)은 적색광에서 가장 낮았고, 청색광에서 15%로 가장 높았으며, 청색광의 비율이 높아짐에 따라 건물율이 높아지는 경향을 보였다. 3. 광질별 총 엽록소 함량은 환기처리 하의 혼합광 R7:B3 및 R5:B5에서 29.5 ${\mu}g/g$ FW와 31.2 ${\mu}g/g$ FW으로 각각 가장 높게 나타났다. 광합성에 관여하는 carotenoid 함량에 있어서도 모든 광질에서 환기 처리 시 높게 나타났다. 이상의 결과는 덩굴용담의 기내배양은 배양목적에 따른 광질의 선택이 중요한 요소이며, 발근을 위해서는 적색광을 처리함이 좋고, 건전한 식물체의 생장은 혼합광 R7:B3에서 양호한 것으로 나타났다. 특히 모든 광질 하에서 환기처리가 건전한 줄기생장 및 발근을 촉진하는 것으로 나타나 이 식물의 효율적인 기내생장을 위해서 반드시 고려해야 할 내용으로 관찰되었다.

• 한국재료학회지
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• 제16권3호
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• pp.145-150
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• 2006

Various colors of light emitting diodes(LED) and four-band white light sources are obtained using a violet LED and various phosphor films. $BaMg_2Al_{16}O_{27}:Eu\;(blue),\;SrGa_2S_4:Eu\;(green),\;and\;Eu(TTA)_3(PTA)$ (red) phosphors are dispersed in poly-vinyl-alcohol aqueous solutions, and phosphor films are prepared by coating the suspensions to PET film. The narrow band emission of $Eu(TTA)_3(PTA)$ phosphor has excellent red luminescent property for four-band white light excited by the violet LED.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.851-854
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• 2001

Europium-activated Ga$_2$O$_3$powders were prepared by modified "Pechini method" from mixed aqueous solutions of gallium nitrate, europium nitrate, ethylene glycol and citric acid. The formation process and structure of the phosphor powders were investigated by means of TG/DTA, XRD and SEM. It has been found that the phosphor powders were amorphous up to 50$0^{\circ}C$ and changed into crystalline $\beta$-Ga$_2$O$_3$phase above $600^{\circ}C$. The resulting nano-sized powders were obtained. Red luminescence in emission spectra were observed at room temperature.

• 한국전기전자재료학회논문지
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• 제18권9호
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• pp.846-850
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• 2005

[ $SrTiO_3$ ]:Al, Pr red phosphors for FED were synthesized by solid state reaction method. The dependence of their luminescent properties on Sr and Al concentration was investigated. The $SrTiO_3$: Al, Pr phosphors showed the characteristic X-ray diffraction patterns of the perovskite structure. Photoluminescence intensity and lattice constant in $SrTiO_3$: Al, Pr phosphors changed in quite a similar manner with Sr concentration. Photoluminescence intensity increased with increasing lattice constant, and the decrease of photoluminescence intensity and lattice constant occurred in the vicinity of 1 mol Sr concentration.

• 한국세라믹학회지
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• 제36권5호
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• pp.478-482
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• 1999

SrTiO3 :Al, Pr phosphor as an oxide compound phosphor is expect to be applied for a field emission display(FED). In this phosphor the excitation spectrum shows a different tendency according to an addition Al3+ and Pr3+ In this excitation spectrum the main peak at 359 nm represent excitation level of Pr3+(1S0longrightarrow1D2 transition) and the absorption characteristic according to Ti/Sr molar ratio is influenced by the structure symmetry. The emission spectrum exhibits the red luminescence with the radiative decay of the 1D2 states(1D2 longrightarrow3H4 transition) The concentration quenching phenomena at 1D2 state shows up as Al3+ and Pr3+ ion concentration increases.

• 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.