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

Abstract

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)(1wt%):PFCz-DPS1-OXD5∕PFN-OH∕Al exhibited efficient white light emission at the Commission Internationale de I’Eclairage coordinates of (0.33, 0.34) and a maximum luminance efficiency of 16.9cd∕A and brightness of 22100cd∕m2.