Heterocyclic compound, organic light emitting device comprising the same and composition for organic material layer of organic light emitting device

A heterocyclic compound represented by the following Chemical Formula 1:

• wherein, in Chemical Formula 1,
• X is O;
• or S;
• R1 to R5 are the same as or different from each other, and each independently selected from the group consisting of hydrogen;
• deuterium;
• and a phenyl group;
• X1 to X3 are N;
• or CRe, and at least one of X1 to X3 is N;
• L1 is a substituted or unsubstituted C6 to C60 arylene group;
• or a substituted or unsubstituted C2 to C60 heteroarylene group, wherein the heteroarylene group does not contain a nitrogen atom;
• Ar1 and Ar2 are the same as or different from each other, and each independently a substituted or unsubstituted C1 to C60 alkyl group;
• a substituted or unsubstituted C6 to C60 aryl group;
• or a substituted or unsubstituted C2 to C60 heteroaryl group, wherein the heteroaryl group does not contain a nitrogen atom;
• Lin is a substituted or unsubstituted C6 to C20 arylene group;
• Chemical Formula 1 has a deuterium content of greater than or equal to 20% and less than or equal to 100%;
• Re is hydrogen;
• deuterium;
• a substituted or unsubstituted C1 to C60 alkyl group;
• or a substituted or unsubstituted C6 to C60 aryl group;
• a and p are an integer of 0 to 3;
• q is an integer of 1 to 5;
• n is an integer of 0 to 2;
• and
• when n is an integer of 2 or p, a and q are 2 or greater, substituents in the parentheses are the same as or different from each other,
• wherein, when
• of Chemical Formula 1 are expressed as an unsubstituted biphenyl group, the biphenyl group is represented by any one of the following structural formulae:
• wherein Chemical Formula 1 is represented by a combination of the following Structural Formula A to the following Structural Formula C:
• in Structural Formula A to Structural Formula C,
• is a position to which Structural Formulae A to C each bond;
• and
• Structural Formula A and Structural Formula B;
• or Structural Formula A has a deuterium content of 20% to 100%,
• Structural Formula C has a deuterium content of 10% or less,
• wherein when n is an integer of 0, then any one of R1 to R5 is deuterium.