Patent ID: 8420230

Claim:
An organic light emitting diode (OLED) comprising: a substrate; a first electrode formed on the substrate, the first electrode having a second surface facing the substrate and a first surface opposite to the substrate; an organic layer formed on the first electrode, the organic layer facing the first surface of the first electrode; a second electrode formed on the organic layer, the second electrode having a first surface facing the organic layer and a second surface opposite to the organic layer; and a luminescent efficiency improvement layer formed on at least one of the second surface of the second electrode and the second surface of the first electrode, the luminescent efficiency improvement layer comprising a compound represented by Formula 1: wherein X 1 is N or a group represented by C—(Ar 1 ) a —R 1 ; X 2 is N or a group represented by C—(Ar 2 ) b —R 2 ; X 3 is N or a group represented by C—(Ar 3 ) c —R 3 ; X 4 is N or a group represented by C—(Ar 4 ) d —R 4 ; X 5 is N or a group represented by C—(Ar 5 ) e —R 5 ; X 6 is N or a group represented by C—(Ar 6 ) f —R 6 , with the proviso that at least one of X 1 to X 6 is N; Ar 1 to Ar 6 are each independently a substituted or unsubstituted C 6 -C 30 arylene group or a substituted or unsubstituted C 2 -C 30 heteroarylene group; R 1 to R 6 are each independently a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, a substituted or unsubstituted C 1 -C 30 alkyl group, a substituted or unsubstituted C 1 -C 30 alkoxy group, a substituted or unsubstituted C 1 -C 30 acyl group, a substituted or unsubstituted C 2 -C 30 alkynyl group, a substituted or unsubstituted C 6 -C 3 aryl group, or an unsubstituted C 2 -C 30 heteroaryl group, wherein at least two adjacent groups of R 1 to R 6 are optionally bonded to each other to form a saturated or unsaturated ring, a substituent of the substituted C 6 -C 30 aryl group is a halogen atom, a hydroxyl group, a nitro group, a cyano group, an amino group, an amidino group, a hydrazine, a hydrazone, a carboxyl group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C 1 -C 30 alkyl group, a C 1 -C 30 alkenyl group, a C 1 -C 30 alkynyl group, a C 6 -C 30 aryl group, a C 7 -C 20 arylalkyl group or a C 3 -C 30 heteroarylalkyl group; and a, b, c, d, e and f are each independently an integer of 0 to 10.