High-efficiency white organic light-emitting devices with a non-doped yellow phosphorescent emissive layer

► We introduce a simplified architecture for phosphorescent white organic light-emitting device. ► The key concept of device fabrication is combination of doped blue emissive layer (EML) with non-doped ultra-thin yellow EML. ► Doping concentration of the blue EML and thickness of the yellow EML are sequentially adjusted. ► High device performance is achieved due to improved charge carrier balance as well as two parallel emission mechanisms in the EMLs.