Efficient single-active-layer organic light-emitting diodes with fluoropolymer buffer layers

In the present Letter, efficient organic light-emitting diodes (OLEDs) with tris(8-hydroxyquinolino) aluminum (Alq3) as a single-active layer have been prepared by using a series of fluoropolymer buffer layers. The OLEDs with a 10-nm-thick poly(tetrafluroethylene-perfluoroalkylvinylethers) (PFA) buffer layer had a current efficiency of 4.46cd∕A at a current density of 2000A∕m2, whereas conventional double-layer OLEDs with N,N′-bis-(1-naphthyl)-N,N′-diphenyl-1,1′-biphenyl-4,4′-diamine (NPB) and Alq3 showed a current efficiency of only 3.81cd∕A at the same condition in our experiment. The effect of the insulating fluoropolymer buffer layers could be interpreted to enhance hole injection and improve carrier balance.