Doping-free orange and white phosphorescent organic light-emitting diodes with ultra-simply structure and excellent color stability

•Efficient simplified doping-free orange and white OLEDs are demonstrated.•White devices have stable spectra with CIE coordinates of (0.38, 0.44).•The maximum efficiency of white devices is 33.6 cd/A (30.1 lm/W).•The operational mechanism of orange and white OLEDs is discussed.

We demonstrate simplified doping-free orange phosphorescent organic light-emitting diodes (OLEDs) based on ultrathin emission layer. The optimized orange device has the maximum current efficiency of 52.1 cd/A and power efficiency of 36.3 lm/W, respectively. Efficient simplified doping-free white OLEDs employing blue and orange ultrathin emission layers have excellent color stability, which is attributed to the avoidance of the movement of charges recombination zone and no differential color aging. One white device exhibits high efficiency of 33.6 cd/A (30.1 lm/W). Moreover, the emission mechanism of doping-free orange and white OLEDs is also discussed.

Graphical abstractThe schematic architecture (a) and proposed energy-level of the orange devices (b).Figure optionsDownload full-size imageDownload as PowerPoint slide