Light emitting element, polycyclic compound for the same, and display device including the same

A polycyclic compound represented by Formula 1:

• wherein, in Formula 1,
• X is NRa, CRbRc, SiRdRe, O, or S,
• R1 and R2 are each independently represented by Formula 2,
• R3 to R6 are each independently a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 10 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,
• Ra to Re are each independently a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 10 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,
• a and b are each independently an integer of 1 to 4,
• c is an integer of 0 to 3, and
• d is an integer of 0 to 4,
• and
• wherein, in Formula 2,
• Rs is a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 10 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, and
• e is an integer of 1 to 5.

A display device comprising:

• a base layer;
• a circuit layer on the base layer;
• and
• a display element layer which is on the circuit layer and comprises a light emitting element,
• wherein the light emitting element comprises a first electrode, a second electrode on the first electrode, and an emission layer 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,
• X is NRa, CRbRc, SiRdRe, O, or S,
• R1 and R2 are each independently represented by Formula 2,
• R3 to R6 are each independently a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 10 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,
• Ra to Re are each independently a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 10 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,
• a and b are each independently an integer of 1 to 4,
• c is an integer of 0 to 3, and
• d is an integer of 0 to 4,
• wherein, in Formula 2,
• Rs is a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 10 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, and
• e is an integer of 1 to 5:
• wherein, in Formula HT-1,
• A1 to A8 are each independently N or CR51,
• L1 is 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,
• Ya is a direct linkage, CR52R53, or SiR54R55,
• Ar1 is 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, and
• R51 to R55 are each independently a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted silyl group, a substituted or unsubstituted thio group, a substituted or unsubstituted oxy group, a substituted or unsubstituted amine group, a substituted or unsubstituted boron group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 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, and/or are bonded to an adjacent group to form a ring,
• and
• wherein, in Formula ET-1,
• at least one among X1 to X3 is N, and each of the remaining X1 to X3 is CR56,
• R56 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 of 2 to 60 ring-forming carbon atoms,
• b1 to b3 are each independently an integer of 0 to 10,
• Ar2 to Ar4 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, and
• L2 to L4 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.