High efficiency single-doped white phosphorescent light-emitting diodes

Abstract

Efficient polymer white-light-emitting diodes (WPLEDs) have been fabricated with a single emissive layer, blue-green fluorescence polymer doped with a red phosphorescent dye. The device structure consists of ITO/poly(ehtlenedioxythiophene):poly(styrene sulfonic acid) (PEDOT:PSS)/poly(N-vinylcarbazole) (PVK) /poly(9,9-dioctylfluorene) (PFO): Ir-complex (Ir(DMFPQ)2pbm) /CsF/Al. Energy transfer occurred from PFO to Ir(DMFPQ)2pbm, leading to electroluminescence quench of PFO. Pure and efficient white light emission was realized by tuning the weight ratio of PFO:Ir(DMFPQ)2pbm to 99.7: 0.3. The maximum current efficiency and luminance of WPLEDs were 9.6cd/A at 7.8V and 13491cd/m2 at 11.4V, respectively.