Heterocyclic compound, organic light-emitting diode including the heterocyclic compound, and flat display device including the organic light-emitting diode

A heterocyclic compound represented by Formula 1 below:

• wherein
• R1 to R11 are each independently a hydrogen atom, a deuterium atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, a carboxyl group, a substituted or unsubstituted C1-C30 alkyl group, a substituted or unsubstituted C2-C30 alkenyl group, a substituted or unsubstituted C2-C30 alkynyl group, a substituted or unsubstituted C1-C30 alkoxy group, a substituted or unsubstituted C3-C30 cycloalkyl group, a substituted or unsubstituted C3-C30 cycloalkenyl group, a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted C2-C30 heteroaryl group, a substituted or unsubstituted C6-C30 aryloxy group, a substituted or unsubstituted C6-C30 arylthio group, or a group represented by N(Q1)(Q2) where Q1 and Q2 are each independently a hydrogen atom, a deuterium atom, a substituted or unsubstituted methyl group, a substituted or unsubstituted ethyl group, a substituted or unsubstituted propyl group, a substituted or unsubstituted butyl group, a substituted or unsubstituted pentyl group, a substituted or unsubstituted phenyl group, a substituted or unsubstituted pyridinyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted anthryl group, a substituted or unsubstituted fluorenyl group, a substituted or unsubstituted carbazolyl group, or a substituted or unsubstituted pyrimidinyl group, provided that R11 is not a phenyl, and
• L1 is a substituted or unsubstituted C6-C30 arylene group, or a substituted or unsubstituted C3-C30 heteroarylene group, and a is an integer of 1 or 2, wherein if a is 2, two L1 are identical to or different from each other.