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Electrical and Optical Properties of OLEDs Depending on the Layer Change of HIL Teflon-AF and EIL Li2CO3

정공주입층재료 Teflon-AF와 전자주입층재료 Li2CO3의 층수 변화에 따른 유기발광다이오드의 전기·광학적 특성

  • Kwang, Yong-Gil (Department of Electrical Engineering, Kwangwoon University) ;
  • Hong, Jin-Woong (Department of Electrical Engineering, Kwangwoon University)
  • 강용길 (광운대학교 전기공학과) ;
  • 홍진웅 (광운대학교 전기공학과)
  • Received : 2013.11.04
  • Accepted : 2013.11.28
  • Published : 2014.01.01

Abstract

It was firstly found in 1st group element. Recently, it has been reported on the improvement of efficiency of the OLEDs by introducing thin layer of some carbonate materials of alkali metal. In order to improve the efficiency of OLEDs which is one of the next generation displays, we have studied the electrical characteristics of the device depending on the thickness ratio of the hole-injection layer to the electron-injection layer. Teflon-AF was used as the hole-injection material, and alkali-metal carbonates of $Li_2CO_3$ were used as the electron-injection materials. To obtain a proper thickness ratio, we manufactured. Four types of devices with the thickness ratio of HIL to EIL were made to be 1 : 4, 2 : 3, 3 : 2, and 4 : 1. The results of electrical and optical properties showed that the device with the thickness ratio of 4 : 1 is the most excellent result. In addition, to prepare a four-layer device by inserting the ${\alpha}$-NPD is a hole transporting material was compared with three-layer element. As a result, the maximum luminance, the maximum luminous efficiency, maximum external quantum efficiency of about 124 [%], 164 [%], 106 [%] improve was confirmed.

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