High efficient and color stable WOLED using double white emissive layer

For the high luminance and quantum efficiency, we propose a novel structure of white organic light-emitting diode (WOLED) using two white emissive layers (EML). The host material of MADN with the blue dopant of BCzVBi and the red dopant of DCJTB was used for one EML and DPVBi as host material with those dopants for the other EML. By considering the order of the EMLs and their energy band gaps in the device structure, the charge carrier trapping can be generated. They play a role in the barrier function at the EML enhancing the recombination where the holes and electrons were trapped in the DPVBi and MADN. The quantum efficiency can be improved by the charge carrier trapping in the WOLED with the double white EMLs as obtaining 4.23% at 10mA/cm2, and it is vastly superior to that of the WOLED with a single EML. White color balance is also excellent with color coordinates of (0.36, 0.34) in the CIE 1931 (x, y) chromaticity diagram.