Patent ID: 8563143

Claim:
An electroluminescent (EL) device, comprising: a stack structure comprising a hole injection layer, a hole transport layer, an emitting layer and an electron-transport layer sequentially between a first electrode and a second electrode, wherein the electron-transport layer comprises: a first layer directly on the emitting layer as a single layer, the first layer comprising a mixture selected from a ratio of 3:7 to 7:3 of Balq (aluminum(III) bis(2-methyl-8-quinolinato) 4-phenylphenolate) and Alq 3 [Tris-(8-hydroxyquinolinolato)-aluminum], a ratio of 5:5 of Balq and BeBq 2 [Bis(10-hydroxybenzo[h]quinolinato)beryllium], and a ratio of 5:5 of BCP(2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) and BeBq 2 ; and a second layer contacted with the second electrode as a single layer, the second layer formed of a mixture of BeBq 2 and LiF on the first layer, wherein the electron-transport layer including the first layer and the second layer has a thickness of approximately 35 nm, and wherein the emitting layer includes at least one phosphorescent material.