High-efficiency and solution processible multilayer white polymer light-emitting diodes using neutral conjugated surfactant as an electron injection layer

High-efficiency white polymer light-emitting diodes were fabricated by using an yellow-emitting osmium complex Os (fptz)2 (dppe) [fptz=3 -trifluoromethyl-5-(2-pyridyl)-1,2,4-triazole, dppe=cis -1,2-bis-(dipheneyl- phosphino) ethylene] doped into blue fluorescent copolymer based on an ultraviolet-blue light emitting host poly[2,7-(9,9-dioctylfluorene)-co-1,3-(5- carbazolphenylene)] and a blue light emitting component 4-N,N -diphenylaminostilbene (PFCz-DPS1-OXD5) as the emissive layer and a neutral conjugated surfactant, poly[9,9-bis(6′ (diethanolamino)hexyl)-fluorene] (PFN-OH), as the electron injection layer sandwiched between the emissive layer and Al cathode. The device with the configuration of indium tin oxide/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonic acid)/poly(N -vinylcarbazole)/ Os (fptz)2 (dppe) (1 wt %):PFCz-DPS1-OXD5PFN-OHAl exhibited efficient white light emission at the Commission Internationale de I'Eclairage coordinates of (0.33, 0.34) and a maximum luminance efficiency of 16.9 cdA and brightness of 22100 cd m2. © 2008 American Institute of Physics.