Realizing high color-stability in tetra-chromatic white organic light-emitting diodes by strict manipulation of red emissive layer

Tetra-chromatic (Blue-Green-Red-Orange) white organic light-emitting diodes (WOLEDs) with superior color stability was demonstrated. Strong carrier trapping effects of red dyes cause significant color shift in multi-color WOLEDs. The high color stability here is attributed to the decrease of red dye trapping sites and enhancement of effective energy transfer to red dye while maintaining appropriate exciton concentration near red dye. As luminance increased from 1000 to 10 000 cd m(-2), variations in Commission Internationale de L'Eclairage are merely (0.007, 0.007). Furthermore, this color-stable WOLED achieved a color rendering index close to 90 simultaneously. Our work shows the manipulation of red dye is crucial for achieving superior color stability in multi-color WOLEDs.