Enhancement of efficiency for white-organic light-emitting diode with a thin electron-blocking layer

Jung Soo Park, Joo Won Lee, Young Min Kim, Sung Jin Bae, Jin Jang, Jai Kyeong Kim, Byeong Kwon Ju

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Abstract

In this study, we have enhanced the emission property of white-organic light-emitting diodes using the method of inserting the ultrathin electron-blocking layer (thin-EBL) between red-green-blue emissive layers. The devices into which three emissive layers are inserted were fabricated with indium tin oxide/CuPc/[A',A''-di(naphthalene-l-yl)-N,N′-diphenyl- benzidine] (α-NPD/DPVBi/thin-EBL/Alq3/Alq3: 2 wt % 4-(dicyano-methylene)-2-methyl-6-(dirnethylaminostyryl-4tf-pyran (DCM1)/ Alq3/LiF:Al. To enhance the white emission property and improve the efficiency of devices, we suggest the α-NPD as the thin-EBL. According to knowledge of the energy band diagram, α-NPD was inserted between the blue-emitting layer and green-emitting layer. The a-NPD layer showed the effective blocking of electron as a function of thickness. From the Experimental, the effective blocking of electrons through controlling the thin-EBL thickness embodied the balanced white emission and improved the efficiency of the device. In our device with 0.3 nm α-NPD, it had a maximum power efficiency of 3.80 Im/W at 250 cd/m2, a luminance efficiency of 5.14 cd/A at 4.83 mA/m2, a luminance of 1200 cd/m 2 at 100 mA/cm2, and the CIE coordinates were (0.353, 0.357), respectively.

Original languageEnglish
JournalJournal of the Electrochemical Society
Volume152
Issue number11
DOIs
Publication statusPublished - 2005 Dec 2

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ASJC Scopus subject areas

  • Electrochemistry
  • Surfaces, Coatings and Films
  • Surfaces and Interfaces

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