• Title, Summary, Keyword: Dopant

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Investigation of the Emission Performance in PHOLED by Ir(piq)3 and Zn(BTZ)2 Doping in Emitting Layer

  • Park, Won-Hyeok;Kim, Gang-Hun
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.149-149
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    • 2015
  • 본 연구에서는 Host 물질 Alq3와 Dopant 물질 Ir(piq)3, Zn(BTZ)2를 사용한 ITO/NPB/Alq3+ metal complexes/Alq3/LiF/Al 다층 구조의 PHOLED 소자를 제작하고 특성 변화를 파악하였다. Dopant Ir(piq)3를 발광 영역에 도핑하였을 경우에는 소자의 발광 효율이 감소하였다. 이는 Co-deposition 조건에 따른 분자간의 거리가 충분히 가까워지지 않았기 때문이다. 분자간의 거리가 Co-deposition 조건보다 멀게 되면 Host - Dopant 간의 에너지 전달이 제대로 일어날 수 없게 되며, 결과적으로 Host 영역과 Dopant영역에서 각각 발광을 하게 된다. Dopant Zn(BTZ)2를 도핑하였을 경우에는 Host - Dopant 간의 에너지 전달에 의한 효과로 인해, J-V 특성은 50% 이상, L-V 특성은 20% 이상, L-J 특성은 10% 이상 효율이 증가하였다.

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The Luminescent Properties of Red OLED Devices Doped with Two Dopants (2원 첨가 적색 OLED 소자의 발광특성)

  • Kim, Kyong-Min;Ju, Sung-Hoo
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.20 no.6
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    • pp.531-535
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    • 2007
  • To invest the luminescent characteristics of red light emitting OLED device, a dual dopant system was incorporated into the emitting layer. The multiple layer OLED device structure was $ITO(1500\;{\AA})/HIL(200\;{\AA})/a-NPD(600\;{\AA})/EML(300\;{\AA})/Alq_3(200\;{\AA})/LiF(7\;{\AA})/Al(1800\;{\AA})$. The concentrations of the rubrene dopant were tested at 0 vol.%, 3 vol.%, 6 vol.% and 9 vol.%. The maximum device efficiency and life time were obtained at the rubrene dopant concentration of 6 vol.%. Emission spectrum and color coordinate of devices showed no relationship with rubrene dopant concentration. Experiment results show that rubrene dopant absorbs energy from $Alq_3$ host and transfer it to RD1 dopant acting as an energy intermediate and influencing the device efficiency, finally the red light is emitted from the RD1 dopant.

Multi Quantum Well 구조를 이용한 Red에서 Green으로의 energy transfer mechanism의 이해

  • Kim, Gang-Hun;Park, Won-Hyeok
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.145-145
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    • 2015
  • 처음 유기물의 인광 발견 이후 Host-dopant 시스템을 이용하여 Emission layer(EML)을 Co-deopsition 하는 방법으로 주로 인광 유기 발광 다이오드를 제작 하였다. [1] co-deposition을 이용해 만든 유기 발광 다이오드에 많은 장점이 있지만, 반대로 소자를 제작하는데 있어서는 많은 문제점을 가지고 있다. [2-4] 이러한 문제점을 개선하기 위하여 co-deposition 대신 non-doped Multi Quantum Well(MQW) 구조를 사용하여 doping 하지 않는 방법을 이용하는 논문들이 보고 되고 있다. Hole, electron, exciton이 MQW 구조를 지나면서, dopant well 안에 갇히게 되고, 그 안에서 다른 layer 간에 energy transfer와, hole-electron leakage가 줄어 들어, 더 효율적인 유기 발광 다이오드를 만들 수 있게 된다. [5-7] 이 연구에서는 CBP를 Potential Barrier로 사용하고, Ir(ppy)3 (Green dopant), Ir(btp)2 (Red dopant) 를 각각 Potential Well로 사용하였고, 두께는 CBP 9nm, dopant 1nm로 하였다. 이러한 소자를 만들고 dopant를 3개의 well에 적당히 배치하여, 각 well에서의 실험적인 발광 량 과, EML 안에서의 발광 mechanism 그리고 각 potential barrier를 줄여가며 dexter, forster에 의한 energy transfer에 대하여 알 수 있었다.

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Measurement of 2-Dimensional Dopant Profiles by Electron Holography and Scanning Capacitance Microscopy Methods (일렉트론홀로그래피와 주사정전용량현미경 기술을 이용한 2차원 도펀트 프로파일의 측정)

  • Park, Kyoung-Woo;Shaislamov, Ulugbek;Hyun, Moon Seop;Yoo, Jung Ho;Yang, Jun-Mo;Yoon, Soon-Gil
    • Korean Journal of Metals and Materials
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    • v.47 no.5
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    • pp.311-315
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    • 2009
  • 2-dimensional (2D) dopant profiling in semiconductor device was carried out by electron holography and scanning capacitance microscopy methods with the same multi-layered p-n junction sample. The dopant profiles obtained from two methods are in good agreement with each other. It demonstrates that reliability of dopant profile measurement can be increased through precise comparison of 2D profiles obtained from various techniques.

Precise Comparison of Two-dimensional Dopant Profiles Measured by Low-voltage Scanning Electron Microscopy and Electron Holography Techniques

  • Hyun, Moon-Seop;Yoo, Jung-Ho;Kwak, Noh-Yeal;Kim, Won;Rhee, Choong-Kyun;Yang, Jun-Mo
    • Applied Microscopy
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    • v.42 no.3
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    • pp.158-163
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    • 2012
  • Detailed comparison of low-voltage scanning electron microscopy and electron holography techniques for two-dimensional (2D) dopant profiling was carried out with using the same multilayered p-n junction specimen. The dopant profiles obtained from two methods are in good agreement with each other. It demonstrates that reliability of dopant profile measurement can be increased through precise comparison of 2D profiles obtained from various microscopic techniques.

Analysis of n+ emitter properties using Dopant Pastes for Crystalline Silicon Solar Cells (결정질 실리콘 태양전지에 적용하기 위한 Dopant Pastes의 n+ emitter 특성 분석)

  • Lee, Ji-Hun;Cho, Kyeong-Yeon;Choi, Jun-Young;Lee, Soo-Hong
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.15-16
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    • 2007
  • The high efficiency and low cost solar cells in order to it applied a dopant pastes diffusion process. The dopant pastes diffusion process which it uses is easily applied in screen-printing solar cells output line. in this paper, it used the Ferro 99-038 phosphorus diffusion pastes source and it analyzed a sheet resistance and a uniformity degree. And it knew the quality of the sheet resistance which it follows in temperature and time condition. The temperature variable it let and it fixed the time in 7 minutes. It will be able to measure the sheet resistance of $40({\Omega}/sq),\;30({\Omega}/sq),\; 20({\Omega}/sq)$. also average uniformity of the sheet resistance was below 5%.

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Terbium and Tungsten Co-doped Bismuth Oxide Electrolytes for Low Temperature Solid Oxide Fuel Cells

  • Jung, Doh Won;Lee, Kang Taek;Wachsman, Eric D.
    • Journal of the Korean Ceramic Society
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    • v.51 no.4
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    • pp.260-264
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    • 2014
  • We developed a novel double dopant bismuth oxide system with Tb and W. When Tb was doped as a single dopant, a Tb dopant concentration more than 20 mol% was required to stabilize bismuth oxides with a high conductivity cubic structure. High temperature XRD analysis of 25 mol% Tb-doped bismuth oxide (25TSB) confirmed that the cubic structure of 25TSB was retained from room temperature to $700^{\circ}C$ with increase in the lattice parameter. On the other hand, we achieved the stabilization of high temperature cubic phase with a total dopant concentration as low as ~12 mol% with 8 mol% Tb and 4 mol% W double dopants (8T4WSB). Moreover, the measured ionic conductivity of 10T5WSB was much higher than 25TSB, thus demonstrating the feasibility of the double dopant strategy to develop stabilized bismuth oxide systems with higher oxygen ion conductivity for the application of SOFC electrolytes at reduced temperature. In addition, we investigated the long-term stability of TSB and TWSB electrolytes.

The Influence of the Wafer Resistivity for Dopant-Free Silicon Heterojunction Solar Cell (실리콘 웨이퍼 비저항에 따른 Dopant-Free Silicon Heterojunction 태양전지 특성 연구)

  • Kim, Sung Hae;Lee, Jung-Ho
    • Journal of the Korean institute of surface engineering
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    • v.51 no.3
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    • pp.185-190
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    • 2018
  • Dopant-free silicon heterojunction solar cells using Transition Metal Oxide(TMO) such as Molybdenum Oxide($MoO_X$) and Vanadium Oxide($V_2O_X$) have been focused on to increase the work function of TMO in order to maximize the work function difference between TMO and n-Si for a high-efficiency solar cell. One another way to increase the work function difference is to control the silicon wafer resistivity. In this paper, dopant-free silicon heterojunction solar cells were fabricated using the wafer with the various resistivity and analyzed to understand the effect of n-Si work function. As a result, it is shown that the high passivation and junction quality when $V_2O_X$ deposited on the wafer with low work function compared to the high work function wafer, inducing the increase of higher collection probability, especially at long wavelength region. the solar cell efficiency of 15.28% was measured in low work function wafer, which is 34% higher value than the high work function solar cells.

Blister Phenomenon in $TiSi_2$ Thin Flim by Ion Implantation (이온주입에 의한 $TiSi_2$ 박막에서의 Blister 현상)

  • 박형태;김영욱
    • Journal of the Korean Vacuum Society
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    • v.4 no.3
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    • pp.287-292
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    • 1995
  • 단결정 실리콘에 P,B,As 등의 dopant를 이온주입시켰을 때 상부에 스퍼터된 Ti과 고상반응에 의해 형성된 Ti 실리사이드막에 발생되는 blister 현상에 대해 조사했다. Dopant에 관계없이 dose양이 많을수록 Ti 실리사이드막에서 blister의 크기와 밀도가 증가한다. 실리콘 표면에 dopant를 주입한 후 열처리를 하여 damage를 줄여줌으로써 blister의 양을 줄일수 있었다. 이 때 열처리온도가 높을수록 blister의 수가 감소한다.

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Active Matrix OLED Displays with High Stability and Luminous Efficiency by New Doping Method

  • Shibata, Kenichi;Hamada, Yuji;Kanno, Hiroshi;Takahashi, Hisakazu;Mameno, Kazunobu
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.4-6
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    • 2003
  • We have developed the active matrix OLED displays with a high efficiency red emission material which uses an emitting assist (EA) dopant system. The EA dopant (rubrene) did not itself emit but assisted the energy transfer from the host ($Alq_s$) to the red emitting dopant(DCM2). A stable red emission (chromaticity coordinates: x=0.64, y=0.36) was obtained in this cell within the luminance range of 100 - 4000 $cd/m^2$ By using EA dopant system, we can realize the reduction of the power consumption of the OLED display..

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