• Title/Summary/Keyword: Green dopant

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Spodumene Single Crystal Growth by FZ Method (Floating Zone법에 의한 Spodumene 단결정 성장)

  • 강승민;신재혁;한종원;최종건;전병식;오근호
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.3 no.2
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    • pp.162-166
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    • 1993
  • Spodumene$(LiAlLi_2O_6)$ single crystal was grown by Floating Zone process using the image furnace having the halogen lamp as heat sources. The crystal had the dimension of 50~60mm length and 6~8mm diameter. The colors of as-grown crystals were green, black and pale green respectively. The composition of the crystal was analized by XRD and FUR measurement. Growth orientation was examined by Laue back reflection pattern and for measuring the light transmittance, OPtical transmittance was measured.

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Photoluminescence of the Mn-doped ZnGa₂O₄ Phosphors Prepared by Coprecipitation of Metal Salts

  • 고중곤;박희동;김동표
    • Bulletin of the Korean Chemical Society
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    • v.20 no.9
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    • pp.1035-1039
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    • 1999
  • Manganese-activated zincgallate (Zn1-xMnxGa2O4) phosphor as a green phosphor was readily prepared by coprecipitation in aqueous basic solution of metal salts. The obtained product converted to amorphous zincgallate even at 300℃, followed by crystallization at 1000 ℃. The pyrolyzed phosphor showed fine particle, then reduction treatment at 900 ℃ changed into homogeneous shape with slight grain growth(particle size less than 0.5 mm). The photoluminescence characteristics of the zincgallates have been investigated as a function of dopant concentrations, reducing atmospheres and temperatures. Under UV excitation the phosphors displayed the highest green emission efficiency at 504 nm when the specimen oxidized at 1000 ℃ was reduced at 900 ℃ in a mild hydrogen atmosphere (97% N2, 3% H2) with a flow rate of 100 ml/min.

Effects of Laser Doping on Selective Emitter Si Solar Cells (레이져를 이용한 도핑 특성과 선택적 도핑 에미터 실리콘 태양전지의 제작)

  • Park, Sungeun;Park, Hyomin;Nam, Junggyu;Yang, JungYup;Lee, Dongho;Min, Byoung Koun;Kim, Kyung Nam;Park, Se Jin;Lee, Hae-Seok;Kim, Donghwan;Kang, Yoonmook;Kim, Dongseop
    • Current Photovoltaic Research
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    • v.4 no.2
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    • pp.54-58
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    • 2016
  • Laser-doped selective emitter process requires dopant source deposition, spin-on-glass, and is able to form selective emitter through SiNx layer by laser irradiation on desired locations. However, after laser doping process, the remaining dopant layer needs to be washed out. Laser-induced melting of pre-deposited impurity doping is a precise selective doping method minimizing addition of process steps. In this study, we introduce a novel scheme for fabricating highly efficient selective emitter solar cell by laser doping. During this process, laser induced damage induces front contact destabilization due to the hindrance of silver nucleation even though laser doping has a potential of commercialization with simple process concept. When the laser induced damage is effectively removed using solution etch back process, the disadvantage of laser doping was effectively removed. The devices fabricated using laser doping scheme power conversion efficiency was significantly improved about 1% abs. after removal the laser damages.

Luminescence Properties of Zn2SiO4:Mn, M(M=Cr, Ti) Green Phosphors Prepared by Sol-gel Method (졸-겔법으로 제조한 Zn2SiO4:Mn, M(M=Cr, Ti) 녹색 형광체의 발광특성)

  • 안중인;한정화;박희동
    • Journal of the Korean Ceramic Society
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    • v.40 no.7
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    • pp.637-643
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    • 2003
  • In order to improve the photoluminescent properties and crystallinity, Zn$_2$SiO$_4$:Mn, M(M=Cr, Ti) phosphors were synthesized by the sol-gel method. The willemite single phase was obtained at 110$0^{\circ}C$, which is lower temperature than that of the conventional solid-state reaction (130$0^{\circ}C$). The characteristics of fired samples were obtained by a 147 nm excitation source under VUV (Vacuum Ultraviolet). To investigation the effect of co-dopant, the content of Mn and the ratio of $H_2O$ to TEOS was fixed as 2 ㏖% and 36. 1, respectively. The highest emission intensity was obtained when the concentration of Cr and Ti was 0.1 ㏖% relative to Zn$_2$SiO$_4$:Mn. While the emission intensity decrease continuously the decay time improved as increased the Cr concentration. In the case of Ti added samples, however, the emission intensity increase up to 2 ㏖% concentration.

Study on Auger Recombination Control using Barrier SiO2 in High-Quality Polysilicon/Tunneling oxide based Emitter Formation (고품질 polysilicon/tunneling oxide 기반의 에미터 형성 공정에서의 Auger 재결합 조절 연구)

  • Huiyeon Lee;SuBeom Hong;Donghwan Kim
    • Current Photovoltaic Research
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    • v.12 no.2
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    • pp.31-36
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    • 2024
  • Passivating contacts are a promising technology for achieving high efficiency Si solar cells by reducing direct metal/Si contact. Among them, a polysilicon (poly-Si) based passivating contact solar cells achieve high passivation quality through a tunnel oxide (SiOx) and poly-Si. In poly-Si/SiOx based solar cells, the passivation quality depends on the amount of dopant in-diffused into the bulk-Si. Therefore, our study fabricated cells by inserting silicon oxide (SiO2) as a doping barrier before doping and analyzed the barrier effect of SiO2. In the experiments, p+ poly-Si was formed using spin on dopant (SOD) method, and samples ware fabricated by controlling formation conditions such as existence of doping barrier and poly-Si thickness. Completed samples were measured using quasi steady state photoconductance (QSSPC). Based on these results, it was confirmed that possibility of achieving high Voc by inserting a doping barrier even with thin poly-Si. In conclusion, an improvement in implied Voc of up to approximately 20 mV was achieved compared to results with thicker poly-Si results.

All Non-Dopant RGB Composing White Organic Light-Emitting Diodes

  • Yeh, Shi-Jay;Chen, Hung-Yang;Wu, Min-Fei;Chan, Li-Hsin;Chiang, Chih-Long;Yeh, Hsiu-Chih;Chen, Chin-Ti;Lee, Jiun-Haw
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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    • pp.1583-1586
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    • 2006
  • All non-dopant white organic light-emitting diodes (WOLEDs) have been realized by using solid state highly fluorescent red bis(4-(N-(1- naphthyl)phenylamino)phenyl)fumaronitrile (NPAFN) and amorphous bipolar blue light-emitting 2-(4- diphenylamino)phenyl-5-(4-triphenylsilyl)phenyl- 1,3,4-oxadiazole (TPAOXD), together with well known green fluorophore tris(8- hydroxyquinolinato)aluminum $(Alq_3)$. The fabrication of multilayer WOLEDs did not involve the hard-tocontrol doping process. Two WOLEDs, Device I and II, different in layer thickness of $Alq_3$, 30 and 15 nm, respectively, emitted strong electroluminescence (EL) as intense as $25,000\;cd/m^2$. For practical solid state lighting application, EL intensity exceeding $1,000\;cd/m^2$ was achieved at current density of $18-19\;mA/cm^2$ or driving voltage of 6.5-8 V and the devices exhibited external quantum efficiency $({\eta}_{ext})$ of $2.6{\sim}2.9%$ corresponding to power efficiency $({\eta}_P)$ of $2.1{\sim}2.3\;lm/W$ at the required brightness.

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Effect of Thermal Annealing on Nanoscale Thickness and Roughness Control of Gravure Printed Organic Light Emitting for OLED with PVK and $Ir(ppy)_3$

  • Lee, Hye-Mi;Kim, A-Ran;Kim, Dae-Kyoung;Cho, Sung-Min;Chae, Hee-Yeop
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.1511-1514
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    • 2009
  • Organic light emitting layer in OLED device was formed by gravure printing process in this work. Organic surface coated by gravure printing typically showed relatively bad uniformity. Thickness and roughness control was characterized by applying various mixed solvents in this work. Poly (N-vinyl carbazole) (PVK) and fact-tris(2-phenylpyridine)iridium($Ir(ppy)_3$) are host dopant system materials. PVK was used as a host and Ir(ppy)3 as green-emitting dopant. To luminance efficiency of the plasma treatment on etched ITO glass and then PEDOT:PSS spin coated. The device layer structure of OLED devices is as follow Glass/ITO/PEDOT:PSS/PVK+Ir(ppy)3-Active layer /LiF/Al. It was printed by gravure printing technology for polymer light emitting diode (PLED). To control the thickness multi-printing technique was applied. As the number of the printing was increased the thickness enhancement was increased. To control the roughness of organic layer film, thermal annealing process was applied. The annealing temperature was varied from room temperature, $40^{\circ}C$, $80^{\circ}C$, to $120^{\circ}C$.

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Structural and Electrical Properties of (La,Nd,Sr)MnO3 Ceramics for NTC Thermistor Devices

  • Shin, Kyeong-Ha;Park, Byeong-Jun;Lim, Jeong-Eun;Lee, Sam-Haeng;Lee, Myung-Gyu;Park, Joo-Seok;Lee, Sung-Gap
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.35 no.3
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    • pp.292-296
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    • 2022
  • (La0.5Nd0.2Sr0.3)MnO3 specimens were prepared by a solid-state reaction. In all specimens, X-ray diffraction patterns of an orthorhombic structure were shown. The fracture surfaces of (La0.5Nd0.2Sr0.3)MnO3 specimens showed a transgranular fracture pattern be possibly due to La ions (0.122 nm) as a perovskite A-site dopant substituting for Nd ions (0.115 nm) having a small ionic radius. The full-width at half maximum (FWHM) of the Mn 2p XPS spectra showed a value greater than that [8] of the single valence state, which is believed to be due to the overlapping of Mn2+, Mn3+, and Mn4+ ions. The dependence of Mn 2p spectra on the Mn3+/Mn4+ ratio according to sintering time was not observed. Electrical resistivity resulted in the minimum value of 100.7 Ω-cm for the specimen sintered for 9 hours. All specimens show a typical negative temperature coefficient of resistance (NTCR) characteristics. In the 9-hour sintered specimen, TCR, activation energy, and B25/65-value were -1.24%/℃, 0.19 eV, and 2,445 K, respectively.

Growth and upconversion properties of erbium doped $LiNbO_3$ single crystal fibers ($Er^{3+}$ 첨가 $LiNbO_3$ fiber 단결정의 성장 및 upconversion 특성)

  • Yang, Woo-Seok;Suh, Su-Jeong;Lee, Jong-Ho;Tsuguo Fukuda;Yoon, Dae-Ho
    • Proceedings of the Korea Association of Crystal Growth Conference
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    • 1999.06a
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    • pp.321-335
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    • 1999
  • Erbium(Er) doped LiNbO3(Er:LiNbO3) single crystal gibers were grown free of cracks along the c-axis by micro-pulling down method. the Er3+ concentration was distributed homogeneously along the growth axis. The samples for optical characterization were cut from as-grown single crystal fibers and polished. When the 980 nm light was incident on the sample, upconversion phenomena were observed at the green range of wavelength 510~570 nm. In addition, the intensity of upconversion was remarkably increased by increasing the concentration of Er2O3 dopant in as-grown Er:LiNbO3 crystals.

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