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Electronics and Telecommunications Research Institute (한국전자통신연구원)
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Correlation between optimized thicknesses of capping layer and thin metal electrode for efficient top-emitting blue organic light-emitting diodes

  • Hyunsu Cho (ICT Creativity Research Laboratory, Electronics and Telecommunications Research Institute) ;
  • Chul Woong Joo (ICT Creativity Research Laboratory, Electronics and Telecommunications Research Institute) ;
  • Byoung-Hwa Kwon (ICT Creativity Research Laboratory, Electronics and Telecommunications Research Institute) ;
  • Chan-mo Kang (ICT Creativity Research Laboratory, Electronics and Telecommunications Research Institute) ;
  • Sukyung Choi (ICT Creativity Research Laboratory, Electronics and Telecommunications Research Institute) ;
  • Jin Wook Sin (ICT Creativity Research Laboratory, Electronics and Telecommunications Research Institute)
  • Received : 2022.07.14
  • Accepted : 2022.10.17
  • Published : 2023.12.10
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Abstract

The optical properties of the materials composing organic light-emitting diodes (OLEDs) are considered when designing the optical structure of OLEDs. Optical design is related to the optical properties, such as the efficiency, emission spectra, and color coordinates of OLED devices because of the microcavity effect in top-emitting OLEDs. In this study, the properties of top-emitting blue OLEDs were optimized by adjusting the thicknesses of the thin metal layer and capping layer (CPL). Deep blue emission was achieved in an OLED structure with a second cavity length, even when the transmittance of the thin metal layer was high. The thin metal film thickness ranges applicable to OLEDs with a second microcavity structure are wide. Instead, the thickness of the thin metal layer determines the optimized thickness of the CPL for high efficiency. A thinner metal layer means that higher efficiency can be obtained in OLED devices with a second microcavity structure. In addition, OLEDs with a thinner metal layer showed less color change as a function of the viewing angle.

Keywords

Acknowledgement

Korea Evaluation Institute of Industrial Technology (KEIT), Grant/Award Numbers: 20012560 and 10079671.

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