• Transactions on Electrical and Electronic Materials
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• 제9권1호
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• pp.1-5
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• 2008

ZnS is an attractive material for future optical and electrical devices since it has a direct and wide band gap to provide blue emission at room temperature. In this study, inductively coupled $BCl_3/Ar$ plasma was used to etch ZnS:Mn thin films. The maximum etch rate of 164.2 nm/min for ZnS:Mn was obtained at a $BCl_3(20)/Ar(80)$ gas mixing ratio, an rf power of 700 W, a dc bias voltage of -200V, a total gas flow of 20 sccm, and a chamber pressure of 1Pa. The etch behaviors of ZnS:Mn thin films under various plasma parameters showed that the ZnS:Mn were effectively removed by the chemically assisted physical etching mechanism. The surface reaction of the ZnS:Mn thin films was investigated by X-ray photoelectron spectroscopy. The XPS analysis revealed that Mn had detected on the surface ZnS:Mn etched in $BCl_3/Ar$ plasma.

• 한국전기전자재료학회논문지
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• 제14권8호
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• pp.679-687
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• 2001

It is known that amorphous BaTiO$_3$ thin films have good insulating properties[1][2]. In this investigation, amorphous BaTiO$_3$ thin films were deposited by rf magnetron sputtering on thick BaTiO$_3$ films of AC powder EL devices which were fabricated by screen-printing. The electrical and optical properties of the EL devices were then investigated. Adding amorphous BaTiO$_3$ thin film, it showed that leakage current density was decreased. Especially, leakage current density was decreased more with he sample of 0.5-hour deposition than the sample of 4-hours deposition. This result led to the improvement of luminous efficiency by 11%. It could be concluded that proper amorphous BaTiO$_3$ thin film deposition improved the surface property of dielectric layer.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 추계학술발표대회 논문집
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• pp.239-244
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• 2011

In this paper, we analyzed the electrical characteristics with crack pattern in crystalline solar cell. crystalline solar cells with a thin substrate, even small shocks can be easily damaged. Before the module goes through many processes, because the solar cells are at risk of a crack. That occurred early in the PV module micro-crack is not easily detection by eye test or output test. Because the EL (Electroluminescence) device has been detected using. PV module is made by laminated of a variety of materials. By different properties of each material will affect the crack. For this reason, the crack will grow and affect the output. And We analyzed the three crack patterns in crystalline solar cell. A growth of cracks on crystalline solar cell was interpreted by analysing generated cracks on the PV modules. Based on this interpretation, an electrical output value was calculated by mathematical modeling on electrical output characteristic with each crack patterns.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.918-920
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• 2006

Metal sulfide powders such as MnS, $MoS_2$ and FeS are simply used to the machinery processing improvement agent and solid lubricant in powder metallurgy industrial. And then, metal sulfide powders have received relatively little attention from powder metallurgy. Recently, the portable machine is one of the important interfaces between human or human and electronic machine. With the increase of the intelligent activity, the social and industrial demands for information display device and power source are increasing. The transition metal sulfide materials (FeS, ZnS) have received considerable attention due to the large variety of its electric, optical and magnetic properties. Among the metal sulfide, $FeS_2$ is appealing superior material for applications in $Li-2^{nd}$ battery because of high capacity. ZnS is also a famous phosphor material with various luminescence properties, such as photoluminescence (PL) and electroluminescence (EL). So generally used in the fields of display, sensors and laser. Metal sulfide materials, therefore, are provided for most widely application in all industries. In recent years, material researchers have become increasingly interested in studying with synthesis of metal sulfide.

• 한국응용과학기술학회지
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• 제21권4호
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• pp.274-278
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• 2004

In this study, hetero-electrode structures have been fabricated to increase luminescence efficiency. The presence of a thin layer of Sn or Ag at the organic-aluminum interface enhanced both electron injection efficiency and electroluminescence when compared to OLEDs using homogeneous electrode. In this paper, the effect of the cathode using Sn/Al hetero electrode structure is observed. Electric properties of the OLED using Sn/Al hetero cathode are improved in comparison of only Al cathode. The hetero-electrode existing different energy level induces the advanced structure of OLED can accumulate electron density. The luminescence efficiency of OLED with Sn/Al of Ag/Al cathode is higher because of their higher electron injection efficiency. And, the turn on voltage of the OLED device using Sn thin layer is lowest as about 10 V.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.465-465
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• 2008

Conjugated polymers have attracted much scientific and technological research interest during the past few decades because of their potential use such as polymer light-emitting diodes (PLEDs).1,2 Particularly, lots of phenylene-based polymers such as polyfluorene and its derivatives have been synthesized because of their high photoluminescence quantum efficiencies and thermal stabilities. However, troublesome long wavelength emission in polymer film of polyfluorenes on heating during device formation or operation has been the crucial problem for practical applications. The source of the long wavelength emission was initially believed to be solely due to excimer emission as a result of polymer aggregation. It has also recently been correlated with emissions from ketonic defects in the fluorene units. Many efforts have been made to reduce the tendency to red-shifted emission. Here, we report for the first time the design and synthesis of novel 9,9-spiro bifluornene-based polymers containing heteroatoms such as N, S in its molecular skeleton. Especially, the 9,9-spiro bifluornene-based polymers containing N atom showed stable blue electroluminescence, which did not show spectral change upon thermal annealing.

• 한국전기전자재료학회논문지
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• 제16권9호
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• pp.816-825
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• 2003

Current-voltage-luminance characteristics of organic light-emitting diodes (OLEDs) were measured in the temperature range of 10 K～300 K. Indium-tin-oxide (ITO) was used as an anode and aluminum as a cathode in the device. Organic of N,N'-diphenyl-N,N'-di(m-tolyl)-benzidine (TPD) was used for a hole transporting material, and tris (8-hydroxyquinolinato) aluminum (Alq$_3$) for an electron transporting material and emissive material. And copper phthalocyanine (CuPc), poly(3,4-ethylenedi oxythiophene);poly(styrenesulfonate) (PEDOT:PSS), and poly(N-vinylcarbazole) (PVK) were used for hole-injection buffer layers. From tile analysis of electroluminescence (EL) and photoluminesccnce (PL) spectra of the Alq$_3$, the EL spectrum is more greenish then that of PL. And the temperature-dependent current-voltage characteristics were analyzed in the double and multilayer structure of OLEDS. Electrical conduction mechanism was explained in the region of high-electric and low-electric field. Temperature-dependent luminous efficiency and operating voltage were analyzed from the current-voltage- luminance characteristics of the OLEDS.

• 공업화학
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• 제16권6호
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• pp.755-759
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• 2005

본 연구는 유기EL의 기초연구로서, 특히 발광재료인 DPAVBi, AVBi 및 DPVBi를 Witting반응과 Wittig-Horner반응으로 합성했다. 이 반응은 Phosphorous ylide와 4-(디페닐아미노)벤즈알데히드, 9-안트라알데히드 및 벤조페논으로 행해졌다. 반응생성물의 구조적 특성은 FT-IR, 'H-NMR 스펙트로스코피로서 분석되었으며, 열적 안정성, 반응성 및 PL특성은 융점, 수득율 및 발광스펙트럼으로 각각 분석되었다. 순수한 DPAVBi, AVBi 및 DPVBi의 광전발광스펙트럼은 445 nm, 484 nm 및 450 nm 부근에서 각각 관찰되었다. 본 연구에 있어서 합성된 DPAVBi, AVBi 및 DPVBi는 알데히드, 케톤의 카르보닐기의 ${\alpha}$-위치의 안정성에 따라서 다른 반응특성을 나타냈다.

• 한국응용과학기술학회지
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• 제18권1호
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• pp.7-11
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• 2001

White emission is important for applying organic EL devices to full-color flat panel display and backlight for liquid crystal display. In order to obtain white emission, the use of a light-emitting material which shows the white emission by itself is advantageous for these applications because of its high reliability and productivity. A chelate-metal complex such as zinc bis(2-(2-hydroxyphenyl) benzothiazolate) ($Zn(BTZ)_{2}$ was known to emit white light with a broad electroluminescence. In this study, the electroluminescent characteristics of $Be(BTZ)_{2}$ and $Mg(BTZ)_{2}$, as well as $Zn(BTS)_2$ were investigated using organic electroluminescent devices with the structure of ITO/TPD/ $Be(BTZ)_{2}$, $Mg(BTZ)_{2}$, or $Zn(BTZ)_{2}/Al$. It was found that the device containing $Be(BTZ)_{2}$ showed the highest power efficiency.

• 한국재료학회지
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• 제10권4호
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• pp.290-294
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• 2000

ZnS:Mn TFEL device를 전자선 진공증착법으로 제작하여 전기광학적 특성에 관하여 조사하였다. $Ta_2O_5$ 박막의 산소 결핍에 따른 정전용량을 측정하기 위하여 산소분위기에서 열처리에 따른 AES(Auger electron spectroscopy)와 C-F를 측정하였다. 제작한 EL 소자의 전기장 발광 파장은 550~650nm 였으며 이것은 $Mn^{2+}$ 이온의 $3d^5$ 여기준위인 $^4T_1(^4G)$ 에서 $3d^5$ 기저준위인 $^6A_1(^S)$로의 내각전자전이 피크이다. 열처리를 수행하지 않은 $Ta_2O^5$를 절연층으로 사용한 EL 소자의 발광시작전압은 24~28V이고 색도 좌표값 X=0.5151, Y=0.4202인 황등색 발광을 하였다. $Ta_2O_5$를 절연층으로 사용한 소자가 저전압에서 구동이 가능하므로 EL 소자의 실용화가 기대된다.