한국정보디스플레이학회:학술대회논문집

The Korean Infomation Display Society (한국정보디스플레이학회)
권호 표지

Low roll-off of efficiency with increasing current density in phosphorescent OLEDs

  • Kang, Jae-Wook (School of Materials Science and Engineering, and OLED Center, Seoul National University) ;
  • Lee, Se-Hyung (School of Materials Science and Engineering, and OLED Center, Seoul National University) ;
  • Park, Hyung-Dol (School of Materials Science and Engineering, and OLED Center, Seoul National University) ;
  • Jeong, Won-Ik (School of Materials Science and Engineering, and OLED Center, Seoul National University) ;
  • Yoo, Kyung-Mo (School of Materials Science and Engineering, and OLED Center, Seoul National University) ;
  • Park, Young-Seo (School of Materials Science and Engineering, and OLED Center, Seoul National University) ;
  • Kim, Jang-Joo (School of Materials Science and Engineering, and OLED Center, Seoul National University)
  • Published : 2007.08.27
Download PDF
⟨ Previous Next ⟩

Abstract

We demonstrate that the reduction of quantum efficiency with increasing current density in phosphorescent light emitting diodes (PhOLEDs) is related to the formation of excitons in hole transporting layer based on the analysis of emission spectra and exciton formation zone. By employing dual emitting layerm we could achieve maintaining quantum efficiency at high current density up to $10000\;cd/m^2$ as 13.1% compared to the devices with single emitting layer (S-EML) (${\eta}_{ext}$= 6.9% at $10000\;cd/m^2$).

Keywords