Improvement of viewing angle dependence of bottom-emitting green organic light-emitting diodes with a strong microcavity effect

Nam Su Kim, Dae Yeong Kim, Jae Ho Song, Min Chul Suh

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)

Abstract

The current efficiency and color purity of organic light-emitting diodes (OLEDs) can be easily improved by means of a microcavity structure, but this improvement is typically accompanied by a deterioration in the characteristics of viewing angle. To minimize the angular dependence of the color characteristics exhibited by these strong microcavity devices, we investigated the changes in the optical properties of the green OLED with a bottom resonant structure. This investigation was based on varying the hole transport layer and semitransparent anode thicknesses. The results of optical simulations revealed that the current efficiency and viewing angle characteristics can be simultaneously improved by adjusting the thickness of the two layers. Furthermore, optical simulations predicted that the angular color dependence could be limited to 0.019 in the International Commission on Illumination (CIE) 1976 coordinate system. This optimum condition yielded a current efficiency of ∼134 cd/A. To further reduce this color shift, a nanosized island array (NIA) was introduced through the dewetting process of cesium chloride. By employing NIAs, the color coordinate shift value was reduced to 0.016 in the CIE 1976 coordinate system, and a current efficiency of 130.7 cd/A was achieved.

Original languageEnglish
Pages (from-to)31686-31699
Number of pages14
JournalOptics Express
Volume28
Issue number21
DOIs
Publication statusPublished - 12 Oct 2020

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© 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

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