Enhanced brightness and efficiency of organic light-emitting diodes with an LiF in the Alq3

Highly efficient and bright organic light-emitting diodes have been realized by inserting a thin insulating lithium fluoride (LiF) layer in the tris-(8-hydroxyquinoline) aluminum (Alq₃) with conventional organic layers. By comparing the performances of newly devised devices as a function of the position of the LiF in the Alq₃ layer, the authors propose the optimal position of the LiF in the Alq₃ layer. Experimental results show that the efficiency and brightness of the newly devised device with LiF in the Alq₃ layer were seven times higher than that without LiF in the Alq₃ layer.