• 제목/요약/키워드: organic emitting layer

검색결과 701건 처리시간 0.027초

전면 유기발광 다이오드 기능층 캐핑레이어 적용에 따른 효율상승에 관한 연구 (A Study on the Efficiency Effects of Capping Layer on the Top Emission Organic Light Emitting Diode)

  • 이동운;조의식;전용민;권상직
    • 반도체디스플레이기술학회지
    • /
    • 제21권3호
    • /
    • pp.119-124
    • /
    • 2022
  • Top emission organic light-emitting diode (TEOLED) is commonly used because of high efficiency and good color purity than bottom - emission organic light-emitting device (BEOLED). Unlike BEOLED, TEOLED contain semitransparent metal cathode and capping layer. Because there are many characteristics to consider just simple thickness change, optimizing organic thickness of TEOLED for microcavity is difficult. So, in this study, we optimized Device capping layer at unoptimized micro-cavity structure TEOLED device. And we compare only capping layer with unoptimized microcavity structure can overcome optimized micro-cavity structure device. We used previous our optimized micro-cavity structure to compare each other. As a result, it has been found that the efficiency can be obtained almost the same or higher only capping layer, which is stacked on top of the device and controls only the thickness and refractive index, without complicated structural calculations. This means that higher efficiencies can be obtained more easily in laboratories with limited organic materials or when optimizing new structures etc.

백색 OLED의 발광효율 향상을 위한 Dielectric Layer 설계에 관한 연구 (The Study of Dielectric Layer Design for Luminance Efficiency of White Organic Light Emitting Device)

  • 김상기;;구할본
    • 한국전기전자재료학회논문지
    • /
    • 제22권10호
    • /
    • pp.850-853
    • /
    • 2009
  • We have optimized the device structure by using the dielectric layer such as anti-reflection thin film to improve the emitting efficiency of white organic light emitting device (WOLED). Basically, dielectric layer with anti-reflection characteristics can enhance the emitting efficiency of WOLED by compensating the refractive index of organic layer, ITO, and Glass. Here, WOLED was designed and optimized by Macleod simulator. The refractive index of 1.74 was calculated for Dielectric layer and was selected as $TiO_2$. The optimal thicknesses of $TiO_2$ and ITO were 119.3 and 166.6 nm, respectively, at the wavelength of 600 nm. The transmittance of ITO was measured with the thickness variation of dielectric layer and ITO in Organic layer/ITO/Dielectric layer structure. The transmittance of ITO was 95.17% and thicknesses of $TiO_2$ and ITO were 119.3 and 166.6 nm, respectively. This result, calculated and measured values were coincided.

유기 전기 발광 소자에서 $\alpha$-septithiophene을 이용한 buffer layer의 영향 (The effects of buffer layer using $\alpha$-septithiophene on the organic light emitting diode)

  • 이기욱;임성택;신동명;박종욱;박호철
    • 한국전기전자재료학회:학술대회논문집
    • /
    • 한국전기전자재료학회 2002년도 춘계학술대회 논문집 디스플레이 광소자 분야
    • /
    • pp.53-56
    • /
    • 2002
  • The effect of $\alpha$-septithiophene (${\alpha}-7T$) layers on the organic light emitting diode(OLED) was studied. The ${\alpha}-7T$ was used for a buffer layer in OLED. Hole injection was investigated and improved emission efficiency. The OLEDs structure can be described as indium tin oxide(ITO)/ buffer layer / hole transporting layer / emitting layer / electron transporting layer / LiF / Al. The hole transporting layer were composed of N,N-diphenyl-N,N-di(3-methylphenyl)-1,1-biphenyl-4,4-diamine(TPD), and N,N-di(naphthalene-1-ly)-N,N-diphenyl-benzidine( ${\alpha}$-NPD). The emitting layer, and electron transporting layer consist of tris(8-hydroxyquinolinato) aluminum($Alq_3$). All organic layer were deposited at a background pressure of less than $10^{-6}$ torr using ultra high vacuum (UHV) system. The ${\alpha}-7T$ layer can substitute the hole blocking layer, and improve hole injection properties.

  • PDF

Effects of Buffer Layer in Organic Light-Emitting Diodes Using Poly(N-vinylcarbazole)

  • Chung, Dong-Hoe;Hong, Jin-Woong;Kim, Tae-Wan
    • 한국응용과학기술학회지
    • /
    • 제20권2호
    • /
    • pp.173-176
    • /
    • 2003
  • We have seen the effects of buffer layer in organic light-emitting diodes using poly(N-vinylcarbazole)(PVK). Polymer PVK buffer layer was made using static spin-casting method. Two device structures were made; one is ITO/TPD/Alq3/Al as a reference and the other is ITO/PVK/TPD/Alq3/Al to see the effects of buffer layer in organic light-emitting diodes. Current-voltage characteristics, luminance-voltage characteristics and luminous efficiency were measured with a variation of spin-casting speeds. We have obtained an improvement of luminous efficiency by a factor of two and half when the PVK buffer layer is used.

유기발광소자(Organic Light Emitting Diode)의 다층박막에 대한 전기적 특성 연구 (A Study on Electric Characteristics of Multi-layer by Light Organic Emitting Diode)

  • 이정호
    • 한국산업정보학회논문지
    • /
    • 제10권2호
    • /
    • pp.76-81
    • /
    • 2005
  • 본 연구에서는 차세대 디스플레이 소자로 각광을 받고 있는 유기발광 소자의 전기적인 특성을 해석적으로 접근하였다. 기본적인 OLED의 동작 메카니즘은 일함수(work function)가 낮은 음극(cathode) 전극으로부터 주입된 전자(electron)와 양극(anode) 전극으로 주입된 정공(hole)이 수송층을 지나 발광층으로 유입되어 여기상태(exciton state)를 거치며 재결합함으로써 발광되는 것으로 알려져 있다. 따라서 음극과 양극을 통해 들어오는 수송자(carrier)들이 원활한 전자-정공 쌍(electron - hole pair)을 이루기 위해 다층 박막 구조로 소자를 제작하여 높은 에너지 장벽을 완만하게 만들고 또한 박막의 두께를 조절하여 정공과 전자의 이동도 밸런스(balance)를 맞추어 수송자-전자와 정공-들이 수송층(CTL : carrier transport layer)을 통해 발광층(EML : emitting material layer)으로 주입을 용이하게 만든다 따라서 본 논문에서는 유기 발광소자의 최적의 발광특성을 얻기 위해서는 수치 해석을 통한 가장 높은 발광 효율을 가지게되는 박막의 두께를 예측하고 예측된 유기발광소자의 수치해석 값이 실제 제작된 소자의 특성 값과 일치하여 타당성이 있음을 증명하고자 한다.

  • PDF

Correlation between optimized thicknesses of capping layer and thin metal electrode for efficient top-emitting blue organic light-emitting diodes

  • Hyunsu Cho;Chul Woong Joo;Byoung-Hwa Kwon;Chan-mo Kang;Sukyung Choi;Jin Wook Sin
    • ETRI Journal
    • /
    • 제45권6호
    • /
    • pp.1056-1064
    • /
    • 2023
  • The optical properties of the materials composing organic light-emitting diodes (OLEDs) are considered when designing the optical structure of OLEDs. Optical design is related to the optical properties, such as the efficiency, emission spectra, and color coordinates of OLED devices because of the microcavity effect in top-emitting OLEDs. In this study, the properties of top-emitting blue OLEDs were optimized by adjusting the thicknesses of the thin metal layer and capping layer (CPL). Deep blue emission was achieved in an OLED structure with a second cavity length, even when the transmittance of the thin metal layer was high. The thin metal film thickness ranges applicable to OLEDs with a second microcavity structure are wide. Instead, the thickness of the thin metal layer determines the optimized thickness of the CPL for high efficiency. A thinner metal layer means that higher efficiency can be obtained in OLED devices with a second microcavity structure. In addition, OLEDs with a thinner metal layer showed less color change as a function of the viewing angle.

마이크로캐비티 OLED의 전극과 유기물층 두께가 발광 스펙트럼에 미치는 영향 (Influence of Electrode and Thickness of Organic Layer to the Emission Spectra in Microcavity Organic Light Emitting Diodes)

  • 김창교;한가람;김일영;홍진수
    • 한국정밀공학회지
    • /
    • 제29권11호
    • /
    • pp.1183-1189
    • /
    • 2012
  • Organic light-emitting diodes (OLEDs) using microcavity effect have attracted great attention because they can reduce the width of emission spectra from organic materials, and enhance brightness from the same material. We demonstrate the simulation results of the radiation properties from top-emitting organic light-emitting diodes (TE-OLEDs) with microcavity structures based on the general electromagnetic theory. Organic materials such as N,N'-di (naphthalene-1-yl)-N,N'-diphenylbenzidine (NPB) as a hole transport layer and tris (8-hydroxyquinoline) ($Alq_3$) as emitting and electron transporting layer are used to form the OLEDs. The organic materials were sandwiched between anode such as Ni or Au and cathode such as Al, Ag, or Al:Ag. The devices were characterized with electroluminescence phenomenon. We confirmed that the simulation results are consistent with experimental results.

고휘도 유기발광소자 제작 및 특성 (Characteristics and fabrications of high brightness organic light emitting diode(OLED))

  • 장윤기;이준호;남효덕;박진호
    • 한국전기전자재료학회:학술대회논문집
    • /
    • 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
    • /
    • pp.316-319
    • /
    • 2001
  • Organic light emitting diodes(OLEDs) with a hole injection layer inserted between Indium-Tin-Oxide(ITO) anode and hole transport layer were fabricated. The effect of plasma treatment on the surface properties of Indium-Tin-Oxide(ITO) anode were studied. The electrical and optical characteristics of the fabricated organic light emitting diodes(OLEDs) were also studied. The diode including of plasma treated ITO substrate and the hole injection layer, which showed the luminance of 5280 $cd/m^{2}$ at 8 V

  • PDF

고휘도 유기발광소자 제작 및 특성 (Characteristics and fabrications of high brightness organic light emitting diode(OLED))

  • 장윤기;이준호;남효덕;박진호
    • 한국전기전자재료학회:학술대회논문집
    • /
    • 한국전기전자재료학회 2001년도 추계학술대회 논문집
    • /
    • pp.316-319
    • /
    • 2001
  • Organic light emitting diodes(OLEDs) with a hole injection layer inserted between Indium-Tin-Oxide(ITO) anode and hole transport layer were fabricated. The effect of plasma treatment on the surface properties of Indium-Tin-Oxide(ITO) anode were studied. The electrical and optical characteristics of the fabricated organic light emitting diodes(OLEDs) were also studied. The diode including of plasma treated ITO substrate and the hole injection layer, which showed the luminance of 5280 cd/㎡ at 8 V

  • PDF

HTL:EML(DPVBi:NPB)층의 조성비 변화에 따른 청색 유기 발광 소자 개발 (Development of Blue Organic Light-emitting Diodes(OLEDs) Due to Change in Mixed Ratio of HTL:EML(DPVBi:NPB) Layers)

  • 이태성;이병욱;홍진수;김창교
    • 한국전기전자재료학회논문지
    • /
    • 제21권9호
    • /
    • pp.853-858
    • /
    • 2008
  • The structure of organic light-emitting diodes(OLEDs) with typical heterostructure consists of anode, hole injection layer, hole transport layer, light-emitting layer, electron transport layer, electron injection layer, and cathode. 4,4bis[N-(1-napthyl)-N-phenyl-amino]-biphenyl(NPB) used as a hole transport layer and 4'4-bis(2,2'-diphenyl vinyl)-1,1'-biphenyl(DPVBi) used as a blue light emitting layer were graded-mixed at selected ratio. Interface at heterojunction between the hole transport layer and the elecrtron transport layer restricts carrier's transfer. Mixing of the hole transport layer and the emitting layer reduces abrupt interface between the hole transport layer and the electron transport layer. The operating voltage of OLED devices with graded mixed-layer structure is 2.8 V at 1 $cd/m^2$ which is significantly lower than that of OLED device with typical heterostructure. The luminance of OLED devices with graded mixed-layer structure is 21,000 $cd/m^2$ , which is much higher than that of OLED device with typical heterostructure. This indicates that the graded mixed-layer enhances the movement of carriers by reducing the discontinuity of highest occupied molecular orbital(HOMO) of the interface between hole transport layer and emitting layer.