Articles
  • Performance characteristics by inserting MoO3 layer into organic light-emitting diodes
  • Jung Eun Oha, Won Jae Leeb, Sang Geon Parkc and Tae Wan Kima,*
  • a Department of Information Display Engineering, Hongik University, Seoul 04066, Korea b Department of Electronic Engineering, Gachon University, Gyeonggi 13120, Korea c Division of Smart Electrical and Electronic Engineering, Silla University, Busan 46958, Korea
Abstract
In this study, we investigated the performance characteristics optimized by molybdenum trioxide (MoO3) used as a buffer layer between an anode and a hole transport layer. MoO3, which acts as a carrier ladder, allows for easy hole injection. The small difference between the highest occupied molecular orbital (HOMO) level of N,N'-Bis (3-methylphenyl)-N,N'- diphenylbenzidine (TPD) and the conduction band of MoO3 leads to an easy carrier transfer effect. It was found that when the thickness of MoO3 as a buffer layer was 15 nm, the current density was improved by about 3 times and the luminance by about 3.87 times at a voltage of 7 V, compared to those of a basic device without a buffer layer. The 60% lifetime of the device was improved by a factor of 3.17 and 1.55 at the MoO3 layer thickness of 5 nm and 15 nm, respectively, compared to that of the basic device. It was found that when the thickness of MoO3 is more than 15 nm, the thickness of MoO3 acts as a resistance component, thus reducing the current density and luminance characteristics. The electrical and optical characteristics of the device were determined by varying the thickness of the hole-transport layer TPD to be 25, 35, and 55 nm with the fixed layer thickness of MoO3 to 15 nm which showed a high current density and luminance. The current density, luminance, and lifetime of the organic light-emitting diodes were improved by about 2.6 times, 3 times, and 5.5 times, respectively, at the TPD layer thickness of 25 nm and the MoO3 layer thickness of 15 nm.

Keywords: Organic Light-Emitting Diodes, Buffer layer, Molybdenum trioxide.

This Article

  • 2017; 18(11): 787-791

    Published on Nov 30, 2017

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