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 (Al q3) 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 4.46 cdA at a current density of 2000 A m2, whereas conventional double-layer OLEDs with N, N′ -bis-(1-naphthyl)- N, N′ -diphenyl- 1, 1′ -biphenyl- 4, 4′ -diamine (NPB) and Al q3 showed a current efficiency of only 3.81 cdA 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.