• Title/Summary/Keyword: Photoluminescence intensity

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Photo- and Cathod-luminesent Properties of $YNbO_4$ : Bi Phosphors ($YNbO_4에\;Bi^{3+}$가 도핑된 형광체의 빛발광 및 저전압 음극선발광 특성)

  • 한정화;김현정;박희동
    • Journal of the Korean Ceramic Society
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    • v.35 no.3
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    • pp.245-250
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    • 1998
  • Field emission display (FED) is currently being explored as a potential flat panel display technology. The need of new materials for low voltage blue phosphors for FED focused our attention on the $Y_2O_3-Nb_2O_5$ sys-tem. Yttrium niobate doped with $Bi^{3+}$ was prepared by solid state reaction technique and the optimization of the luminescent properties with a control of $Bi^{3+}$ amounts and Y/Nb ratio was studied. Under 254 nm and low voltage electron excitations $Bi^{3+}-activated$ YNbO4 phosphors showed a strong and relatively narrow blue em-ission band with a range of 420 to 450 nm, Especially 0.4wt% $Bi^{3+}\;doped\;YNbO_4$ phosphors with Y/Nb ratio of 1/1 showed the maximum emission intensity. Under low voltage electron excitation maximum emission in-tensity appeared at the Y/Nb ratio of 0.495/0.505.

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Photoluminescence properties of core/shell-type $LnPO_4:Eu/LnPO_4$ (Ln=La, Gd) nanophosphors

  • Oh, Jae-Suk;Jung, Ha-Kyun
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08b
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    • pp.1551-1554
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    • 2007
  • To overcome defect due to large surface of nanoparticle, a redispersible Eu doped $LnPO_4:LnPO_4$ core/shell nanoparticles were prepared in a highboiling coordinating solvent. The particle size of the synthesized core/shell nanophosphors was estimated to be about 8 nm by TEM. In this core/shell nanoparticle, the concentration of Eu ion was optimized on the basis of the emission intensity under UV ray excitation. Also, the PL properties of the nanophosphors have been compared with those of the $LnPO_4:Eu$ nanoparticles.

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Structural and Optical Properties of ZnO Thin Films Grown at Various Plume-Substrate Angles by Pulsed Laser Deposition (펄스레이저 증착법에서 기판-플룸 각 변화가 ZnO 박막의 구조 및 광학적 특성에 미치는 영향)

  • 강정석;강홍성;김재원;이상렬
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.3
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    • pp.329-332
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    • 2004
  • ZnO thin films were grown with different plume-substrate angles by pulsed laser deposition (PLD) to control the amount of ablated species arriving on a substrate per laser shot. The angles between plume propagation direction and substrate plane (P-S angle) were 0$^{\circ}$, 45$^{\circ}$ and 90$^{\circ}$. The growth time was changed in order to adjust film thickness. From the XRD pattern exhibiting a dominant (002) and a minor (101) XRD peak of ZnO, all films were found to be well oriented along c-axis. From the AFM image, it was found that the grain size of ZnO thin film was increased, as P-S angle decreased. UV intensity investigated by PL (Photoluminescence) increased as P-S angle decreased.

Thermal degradation properties of blue emitting phosphor particles prepared by the spray pyrolysis for PDP (분무열분해공정에서 제조된 PDP용 청색형광체의 열화특성)

  • Kang, Yun-Chan;Lee, Dong-Youl;Park, Hee-Dong
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.07b
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    • pp.1060-1062
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    • 2002
  • Spherical and dense BAM phosphor particles were prepared by spray pyrolysis. The key idea of dense BAM particles is to lead gelation in droplets, which was successfully achieved by using the aluminum polycation as the precursor solution for the spray pyrolysis. The BAM phosphor particles prepared by spraying the aluminum polycation solution have completely spherical shape and dense structure. When directly applied to make phosphor film on the glass by the screen-printing method, the prepared spherical BAM phosphor particles showed better packing density and surface morphology than that of commercial one, which has irregular shape and large particle size. It was also found that the thermal degradation in the photoluminescence intensity for dense and spherical BAM particles was less than that of commercial one.

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Sol-gel synthesis and luminescence of $Zn_2SiO_4$:Mn, Al phosphor (Sol-gel법에 의한 $Zn_2SiO_4$:Mn, Al 형광체의 합성과 발광특성)

  • Kim, Chang-Jun;Kwon, Myoung-Seok
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.11a
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    • pp.271-278
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    • 2006
  • Green light emitting $Zn_2SiO_4$Mn and Al co-doped $Zn_2SiO_4$:Mn phosphor were synthesized by a sol-gel method combined with a furnace firing. The luminescent properties of the sample have been investigated. We have found that the phosphor powder with uniform shape show the maximum luminescent intensity when it is prepared with sol-gel method and fired at relatively high temperature ($1100{\sim}1300^{\circ}C$).

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Fabrication of Nano-photonic Crystals with Lattice Constant of 460-nm by Inductively-coupled Plasma Etching Process (유도결합형 플라즈마 식각공정을 통해 제작된 460 nm 격자를 갖는 나노 광결정 특성)

  • Choi, Jae-Ho;Kim, Keun-Joo
    • Journal of the Semiconductor & Display Technology
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    • v.5 no.2 s.15
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    • pp.1-5
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    • 2006
  • The GaN thin film on the 8 periods InGaN/GaN multi-quantum well structure was grown on the sapphire substrate using metal-organic chemical vapor deposition. The nano-scaled triangular-lattice holes with the diameter of 150 nm were patterned on a polymethylmethacrylate blocking film using an electron beam nano-lithography system. The thin slab and two-dimensional photonic crystals with the thickness of 28 nm were fabricated on the GaN layer for the blue light diffraction sources. The photonic crystal with the lattice parameter of 460 nm enhances spectral intensity of photoluminescence indicating that the photonic crystals provides the source of nano-diffraction for the blue light of the 450-nm wavelength.

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Optical Excitation and Emission Spectra of YNbO4 : Eu3+

  • Lee, Eun-Young;Kim, Young-Jin
    • Journal of the Korean Electrochemical Society
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    • v.12 no.3
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    • pp.234-238
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    • 2009
  • In the excitation spectra of $YNbO_4$ : $Eu^{3+}$, the charge transfer (CT) band around 270 nm due to $[NbO_4]^{3-}$$-Eu^{3+}$ interaction and sharp excitation peaks by f-f transition of $Eu^{3+}$ strongly appeared simultaneously. CT band depended on the structural properties of powders, showing the red-shift with increasing the crystallinity, while the f-f transition peaks were independent of the crystallinity. For $YNb_{1-x}Ta_xO_4$ : $Eu^{3+}$ (x = 0.05.0.2), $[TaO_4]^{3-}$. configuration was locally constructed, leading to the blue-shift in CT band and the decrease in the red emission intensity with increasing the Ta content.

High resolution patterning of polyfluorene derivative containing photo cross-linkable oxetane units

  • Park, Moo-Jin;Lee, Jeong-Ik;Chu, Hye-Yong;Kim, Seong-Hyun;Zyung, Taeh-Young;Hwang, Do-Hoon
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07b
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    • pp.1419-1420
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    • 2005
  • We have synthesized a photo patternable blue lightemitting polyfluorene (PF) derivative containing cross-linkable oxetane units. Poly(9,9-bis-(4-octyloxyphenyl)- fluorene-2,7-diyl-alt-9,9-bis-((3-hexyloxy-3'- ethyl)-oxetane)-fluorene-2,7-diyl) has been synthesized by Suzuki coupling polymerization. The relationship between patterning property and several variables such as the intensity of the exposed UV light, the concentrations of additives, has been studied by using optical microscope UV/visible spectroscopy, photoluminescence and scanning electron microscope (SEM). We obtained fine patterns with 10 mm resolution using the polymer film after exposure and development. This patterning method using conjugated polymers can be applicable to make fine pixels for PLEDs and OFETs.

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Effects of ZnS Insertion on the Characteristics of CaS:Pb Thin Film Phosphor

  • Park, Sang-Hee Ko;Kang, Seung-Youl;Kim, Kwang-Bok;Kim, Dong-Il;Yun, Sun-Jin
    • 한국정보디스플레이학회:학술대회논문집
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    • 2003.07a
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    • pp.1071-1074
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    • 2003
  • The effects of ZnS insertion on the characteristics of CaS:Pb phosphor were investigated. The intensity of photoluminescence of ZnS inserted CaS:Pb excited by 347nm were increased while that excited by 254nm was unchanged, compared to those of CaS:Pb thin film. The electroluminescent display having ZnS inserted CaS:Pb showed lower threshold voltage and higher efficiency than those of CaS:Pb ELD device.

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Shape Control and Characterization of One-dimensional ZnO Nanostructures through the Synthesis Procedure (합성절차에 따른 1차원 ZnO 나노구조의 형태조절과 특성평가)

  • Kong, Bo-Hyun;Park, Tae-Eun;Cho, Hyung-Koun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.19 no.1
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    • pp.13-17
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    • 2006
  • The one-dimensional ZnO nanostructures prepared through thermal evaporation under various cooling down procedures by changing the flow rates of the carrier gas and the reactive gas were investigated. The nanorod structures were changed into the nanonail types with a broad head through the reduction of the flow rate of the carrier gas. The decrease of the reactive gas reduced the length of the nail heads due to the limited mass transport of reactive gas. The intensity ratio of the ultraviolet emission/green emission of photoluminescence was proportional to the length of the broad head showing a larger surface area. The vertically aligned nanostructures were grown along the [0001] direction of ZnO regardless of the aligned directions. The crystal direction of the nanostructures was determined by that of the initial ZnO crystal.