Efficient Phosphorescent Polymer Yellow-Light-Emitting Diodes Based on Solution-Processed Small Molecular Electron Transporting Layer

Based on a solution-processed small molecular electron transporting layer, efficient multilayer solution-processed polymer yellow-light-emitting diodes were successfully fabricated. The maximum luminance efficiency and power efficiency reached 41.7 cd/A and 12.5 lm/W, respectively, which are comparable to and even over those from the PLEDs based on the vacuum-deposited electron-transporting layer. The solution-processed small molecular electron transporting layer is based on a mixture of three electron-transporting materials TmPyPB, TAZ, and TPBI. By utilization of this mixed system, not only the thickness of the electron-transporting layer can be easily adjusted, but also device efficiency can be improved because of their excellent synthetic properties.