White Organic Light-Emitting Diodes With Different Order of RGB-Emitting Layers

Abstract

To achieve the emissive layers in white organic light-emitting diode (WOLED) for the three primary colors, DCJTB doped in Alq₃, C545T doped in Alq₃, and BCzVBi doped in MADN were applied for red, green, and blue emissive layer, respectively. By stacking all the red, green, and blue emissive layers in a single device, WOLED devices with the color coordinates close to (0.33, 0.33) were successfully fabricated. The structure of the blue–green–red (BGR) type of the three primary color WOLED device was NPB(700 Å)/MADN:BCzVBi-13%(210 Å)/Alq₃:C545T-2%(30 Å)/Alq₃:DCJTB-2%(60 Å)/Alq₃(300 Å)/Liq(20 Å)/Al(1000 Å). Its maximum luminance and luminous efficiency were 25,680 cd m⁻² and 3.79 cd A⁻¹, as well as its white color coordinate was (0.32, 0.31) at 7 V. The structure of blue–red–green (BRG) type of the three primary color WOLED device was NPB(700 Å)/MADN:BCzVB-13%(210 Å)/Alq₃:DCJTB-2%(30 Å)/Alq₃: C545T-2%(60 Å)/Alq₃(300 Å)/Liq(20 Å)/Al(1000 Å). Its maximum luminance and luminous efficiency were 26,010 cd m⁻² and 4.95 cd A⁻¹, as well as its white color coordinate was (0.33, 0.33) at 7 V. Both devices were successfully induced closer to the ideal white emissive lighting source, and three different peaks at 480 nm, 512 nm, and 616 nm could be confirmed at red, green, and blue region in electroluminescence (EL) spectra.

Keywords:

• Different order
• EML
• three primary colors
• WOLED

Acknowledgment

This research was supported by the Research Fund of Korean Academia-Industry Collaboration (San-Hak Hyubdong) Foundation (10-105) in 2010.