Light emitting element and polycyclic compound for the same

A light emitting element comprising:

• a first electrode;
• a second electrode disposed on the first electrode;
• and
• an emission layer disposed between the first electrode and the second electrode, wherein the emission layer comprises:
• a first compound represented by Formula 1;
• and
• at least one of a second compound represented by Formula HT-1 or a third compound represented by Formula ET-1:
• wherein in Formula 1,
• X1 and X2 are each independently N(R4) or O,
• one or two of R1 to R4 are each independently a group represented by Formula 2, and
• the remainder of R1 to R4 are each independently a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 20 ring-forming carbon atoms,
• wherein in Formula 2,
• Y is N(R11), O, or S,
• R5 to R8, R10, and R11 are each independently a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amine group, a substituted or unsubstituted silyl group, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 ring-forming carbon atoms, a substituted or unsubstituted heterocycloalkyl group having 2 to 10 ring-forming carbon atoms, a substituted or unsubstituted aryl group having 6 to 60 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 60 ring-forming carbon atoms,
• R9 is a hydrogen atom or a deuterium atom,
• a, c, and d are each independently an integer from 0 to 4,
• b is an integer from 0 to 3, and
• e is an integer from 0 to 2,
• wherein in Formula HT-1,
• a4 is an integer from 0 to 8, and
• R12 and R13 are each independently a hydrogen atom, a deuterium atom, a substituted or unsubstituted aryl group having 6 to 60 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 60 ring-forming carbon atoms,
• wherein in Formula ET-1,
• at least one of Y1 to Y3 is each N, and
• the remainder of Y1 to Y3 are each independently C(Ra),
• Ra is a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 60 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 60 ring-forming carbon atoms,
• b1 to b3 are each independently an integer from 0 to 10,
• L1 to L3 are each independently a direct linkage, a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms, and
• Ar1 to Ar3 are each independently a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms.