Article

Enhanced Efficiency of Organic Electroluminescence Diode Using PEDOT-PSS/NPD-C60 Hole Injection/Transport Layers
Park KN, Kang HS, Senthilkumar N, Park DW, Choe Y
PEDOT-PSS/NPD-C60 정공 주입/수송 층이 도입된 유기발광소자의 성능 향상 연구
박경남, 강학수, 나타라잔 센틸쿠마르, 박대원, 최영선

Abstract

Vacuum deposited N,N′-di-1-naphthyl-N,N′-diphenyl-1,1′-biphenyl-4,4′-diamine (NPD) as a hole transporting (HTL) materials in OLEDs was placed on PEDOT-PSS, a hole injection layer (HIL). PEDOT-PSS was spin-coated on to the ITO glass. C60-doped NPD-C60(10 wt%) film was formed via co-evaporation process and the morphology of NPD-C60 films was investigated using XRD and AFM. The J-V, L-V and current efficiency of multi-layered devices were characterized. According to XRD results, the deposited C60 thin film was partially crystalline, but NPD-C60 film was observed not to be crystalline, which indicates that C60 molecules are uniformly dispersed in the NPD film. By using C60-doped NPD-C60 film as a HTL, the current density and luminance of multi-layered ITO/PEDOT-PSS/NPD-C60/Alq3/LiF/Al device were significantly increased by about 80% and its efficiency was improved by about 25% in this study.

발광소자(OLED)에서 정공 수송층(hole injection layer, HIL)으로 사용되는 N,N′-di-1-naphthyl- N,N′-diphenyl-1,1′-biphenyl-4,4′-diamine (NPD)가 정공 주입층(hole injection layer, HIL)으로 사용된 PEDOT-PSS 층 위로 진공 증착되었다. PEDOT-PSS 층은 ITO 유리 위에 스핀 코팅되어 제조되었다. 또한, NPD와 C60의 공증착에 의해 C60이 약 10 wt% 도핑된 NPD-C60 층을 제조하였으며, AFM과 XRD를 이용하여 NPDC60 박막의 모폴로지 특성을 관찰하였다. 다층 소자를 제조하여 J-V, L-V 및 전류 효율 특성이 고찰되었다. C60 박막은 국부적인 결정성 구조를 가지고 있으나, NPD-C60 박막에서는 C60 분자가 균일하게 분산되어 C60의 결정성 구조가 확인되지 않았다. 또한, C60의 도핑에 의해서 박막의 표면이 균일해지는 것을 확인하였으며, 박막 내의 전류 밀도가 증가됨을 확인하였다. NPD-C60 박막을 이용하여 ITO/PEDOT-PSS/NPD-C60/Alq3/LiF/Al 다층 소자를 제조하였을 때, 소자의 휘도 측면에서 약 80% 향상 효과가 있었으며, 소자 효율 측면에서도 약 25%의 향상을 기대할 수 있었다.

Keywords: NPD; OLED; C60 doping; current Efficiency; co-evaporation

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Polymer(Korea) 폴리머
Frequency : Bimonthly(odd)
ISSN 0379-153X(Print)
ISSN 2234-8077(Online)
Abbr. Polym. Korea
2023 Impact Factor : 0.4
Indexed in SCIE

This Article

2009; 33(5): 407-412

Published online Sep 25, 2009
Received on Oct 14, 2008
Accepted on Dec 24, 2008

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