Patent ID: 8057917

Claim:
An OLED device comprising, in sequence, an anode, a light-emitting layer that comprises a phosphorescent light-emitting organometallic compound, a hole-blocking layer, and a cathode, and between the hole-blocking layer and the cathode, non-emitting electron transporting layer containing: a) a first compound that has a LUMO value of âˆ’2.7 eV or lower, in an amount greater than or equal to 40% by volume and less than 90% by volume of the layer wherein the first compound is a compound represented by Formula V: wherein: R 1 , R 3 , R 4 , R 7 , R 9 , and R 10 are hydrogen; R 2 and R 8 represent hydrogen or independently selected alkyl groups, R 6 and R 11 represent hydrogen or independently selected aryl groups, and R 5 and R 12 represent aryl groups; and b) at least one second compound that is a low voltage electron transport material, exhibiting a higher LUMO value than the first compound, the total amount of said compound(s) being less than or equal to 40% by volume and more than 10% by volume of the layer, wherein the second compound is represented by either Formula I: wherein M represents a metal; n is an integer of from 1 to 4; and Z independently in each occurrence represents the atoms completing a nucleus having at least two fused aromatic rings; or Formula VII: wherein R 17 , R 18 , R 19 , R 20 , R 21 , R 22 , R 23 and R 24 are hydrogen or substituents; and provided that any of the indicated substituents may join to form further fused rings.