Heterocyclic compound, organic light-emitting device comprising same, and composition for forming organic layer

A heterocyclic compound represented by following Formula 1:

• wherein:
• R1 to R4 are the same as or different from each other and are each independently hydrogen, deuterium, halogen, a cyano group, a substituted or unsubstituted C1 to C60 alkyl group, a substituted or unsubstituted C2 to C60 alkenyl group, a substituted or unsubstituted C2 to C60 alkynyl group, a substituted or unsubstituted C1 to C60 alkoxy group, a substituted or unsubstituted C3 to C60 cycloalkyl group, a substituted or unsubstituted C2 to C60 heterocycloalkyl group, a substituted or unsubstituted C6 to C60 aryl group, a substituted or unsubstituted C2 to C60 heteroaryl group, or —P(═O)R101R102R103, wherein R101, R102, and R103 are the same as or different from each other and are each independently a substituted or unsubstituted C6 to C60 aryl group or a substituted or unsubstituted C2 to C60 heteroaryl group;
• R5 and R6 are the same as or different from each other and are each independently hydrogen, deuterium, halogen, a cyano group, a substituted or unsubstituted C1 to C60 alkyl group, a substituted or unsubstituted C2 to C60 alkenyl group, a substituted or unsubstituted C2 to C60 alkynyl group, a substituted or unsubstituted C1 to C60 alkoxy group, a substituted or unsubstituted C3 to C60 cycloalkyl group, a substituted or unsubstituted C2 to C60 heterocycloalkyl group, a substituted or unsubstituted C6 to C60 aryl group, or a substituted or unsubstituted C2 to C60 heteroaryl group;
• L1 to L8 are the same as or different from each other and are each independently a direct bond, a substituted or unsubstituted C6 to C60 arylene group, or a substituted or unsubstituted C2 to C60 heteroarylene group;
• m, n, o, p, q, r, s, and t are the same as or different from each other and are each independently an integer of 0 to 2, provided that when m, n, o, p, q, r, s, and t are 2, each L1 to L8 defined by these are the same as or different from each other and are each independently selected;
• and
• u is an integer of 0 to 4, provided that when u is 2 to 4, R6 is the same as or different from each other and is each independently selected.