Improving color stability of blue/orange complementary white OLEDs by using single-host double-emissive layer structure: Comprehensive experimental investigation into the device working mechanism

► It is found that multi-emission layer white OLED shows better color stability than single layer one. ► It is important to suppress the direct electron/hole recombination on the charge trapping orange phosphorescent dye. ► The width of the recombination zone in our single hole-type host white OLED is found to be about 3 nm.