High Efficient White-Phosphorescence PLEDs by Using Water/Alcohol-Soluble Polyelectrolyte as an Electron Injection Layer
High efficient white polymer light-emitting diodes (WPLEDs) were fabricated with blue- fluorescent polymers(PFO) and yellow- phosphorescent polymers(PFCz2-NPYIrm5) blending as light emitting layer, and a water/alcohol-soluble polymer poly [(9,9-bis(3′-((N,N-dimethyl)-N-ethylammonium)propyl)-2,7-fluorene)-2,7-(9,9-dioctylfluorene) - 4,7-(2,1,3- benzoselenadiazole)]dibromide(PFN) as electron injection layer. The structure of the devices used here is: ITO/PEDOT-PSS(40nm)/PVK(30nm)/PFO: PFCz2-NPYIrm5 (60nm)/PFN(20nm)/Ba(4nm)/Al(120nm). When the doping concentration of PFCz2-NPYIrm5 was 1% and PFN film thickness was about 20nm, the EL emissions from the host and the guests were observed simultaneously and the efficient white light emission with coordinates of (0.34,0.32) was achieved. A maximum external quantum efficiency of 4.8% and luminous efficiency of 6.6cd/A was obtained at 8.5V.
Aimin Yang, Jingguo Qu and Xilong Qu
N. L. Liu et al., "High Efficient White-Phosphorescence PLEDs by Using Water/Alcohol-Soluble Polyelectrolyte as an Electron Injection Layer", Applied Mechanics and Materials, Vols. 84-85, pp. 494-498, 2011