Highly color-stable and efficient hybrid white organic light-emitting devices by compensating a recombination zone shift in a single host layer

• Color stability of hybrid white OLEDs has been investigated.
• EL spectra, CIE coordinates, and recombination zone have been investigated.
• Current conduction and emission mechanisms were investigated.
• The color stability by compensating blue fluorescent layer was investigated.
• High color-stability and efficiency were obtained.

We have developed highly color-stable and efficient hybrid white organic light-emitting devices (WOLEDs) with multi-emission layers structure consisted of a single host layer doped with fluorescent and phosphorescent guest molecules. The blue fluorescent, red and green phosphorescent molecules were doped into the separated layers of a single host. The color stability of the WOLEDs is substantially improved by embedding an additional blue fluorescent layer which compensates the color change due to the recombination zone shift. The Commission Internationale de L’Eclairage coordinates of the hybrid WOLED change from (0.45, 0.46) to (0.44, 0.45) as the luminance varies from 128 to 23,460 cd/m2. The color-stable WOLED also exhibits a high maximum external quantum efficiency of 15.2% and a current efficiency of 38.8 cd/A.