Efficient blue organic light-emitting devices with charge carrier confining nanostructure formed by wide band gap molecule doping

We report on efficient blue organic light-emitting devices with an emission layer featuring a quasi-molecular quantum dot nanostructure as a charge carrier confining barrier, which was formed by doping a wide band gap molecule, 2-(2-hydroxyphenylbenzoxazole) lithium, into a newly synthesized blue host molecule, 9, 10-bis-[4-(2,.2-diphenylvinyl)-phenyl]-anthracene. The charge carrier confinement was greatly improved by doping with 10% wide band gap molecules, that led to a theoretical molecular quantum dot distance of 33 Angstrom. The device showed enhanced efficiency (similar to5 cd A(-1)) and good colour purity (x = 0. 16, y = 0. 15), while the projected device lifetime reached approximately 20 000 h at 150 cd m(-2).