Delayed fluorescence compound, and organic light-emitting device comprising same

A delayed fluorescence compound represented by Chemical Formula 1 below:

• in Chemical Formula 1, D3 is represented by Chemical Formula 2 below,
• in the above Chemical Formulae, A1 to A6 are each independently a ring structure selected from a substituted or unsubstituted C5-C60 carbocyclic group, a substituted or unsubstituted C2-C60 heterocyclic group, a C6-C60 aryl group, and a C5-C60 heteroaryl group, X1 and X2 are each independently O, N—R7, C(R8)2, or S;
• at least one of X1 and X2 is not N—R7;
• Y1 and Y2 are each independently selected from O or S;
• L3 is a single bond or C6-C60 arylene;
• R1 to R6 are each independently selected from hydrogen, deuterium, a substituted or unsubstituted C1-C60 alkyl group, a substituted or unsubstituted C2-C60 alkenyl group, a substituted or unsubstituted C2-C60 alkynyl group, a substituted or unsubstituted C1-C60 alkoxy group, a substituted or unsubstituted C3-C10 cycloalkyl group, a substituted or unsubstituted C2-C10 heterocycloalkyl group, a substituted or unsubstituted C3-C10 cycloalkenyl group, a substituted or unsubstituted C2-C10 heterocycloalkenyl group, a substituted or unsubstituted C6-C60 aryl group, a substituted or unsubstituted C6-C60 aryloxy group, a substituted or unsubstituted C6-C60 arylthio group, a substituted or unsubstituted C1-C60 heteroaryl group, a substituted or unsubstituted C1-C60 heteroaryloxy group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic heterocondensed polycyclic group;
• and R7 and R8 are each independently selected from hydrogen, deuterium, a substituted or unsubstituted C1-C60 alkyl group, a substituted or unsubstituted C3-C10 cycloalkyl group, a substituted or unsubstituted C6-C60 aryl group, and a substituted or unsubstituted C6-C60 heteroaryl group.