Organic light emitting device

An organic light emitting device comprising:

• an anode;
• a cathode;
• a light emitting layer disposed between the anode and the cathode;
• and
• an electron transport region between the cathode and the light emitting layer,
• wherein the light emitting layer comprises a compound represented by Chemical Formula 1, and
• the electron transport region comprises a compound represented by Chemical Formula 2:
• in Chemical Formula 1,
• X is O or S,
• L is a bond;
• or a substituted or unsubstituted C6-60 arylene,
• Ar is a substituted or unsubstituted C6-60 aryl,
• R and R′ are each independently hydrogen;
• deuterium;
• halogen;
• nitrile;
• nitro;
• amino;
• a substituted or unsubstituted C1-60 alkyl;
• a substituted or unsubstituted C3-60 cycloalkyl;
• a substituted or unsubstituted C2-60 alkenyl group;
• a substituted or unsubstituted C6-60 aryl;
• or a substituted or unsubstituted C2-60 heteroaryl containing at least one heteroatom selected from the group consisting of N, O and S,
• n1 is an integer of 0 to 3, and
• n2 is an integer of 0 to 4,
• in Chemical Formula 2,
• Ar1 and Ar2 are each independently substituted or unsubstituted phenyl, substituted or unsubstituted biphenylyl, or substituted or unsubstituted terphenylyl,
• L1, L2 and L3 are each independently a substituted or unsubstituted C6-60 arylene,
• i, j, and k are each independently 0 or 1,
• A is represented by Chemical Formula 3,
• in Chemical Formula 3,
• X′ is
• Y and Z are each independently hydrogen or deuterium, or Y and Z together form a bond or —W—,
• wherein W is CR17R18, SiR19R20, NR21, O, or S,
• R1 to R21 are each independently hydrogen;
• deuterium;
• a substituted or unsubstituted C1-60 aryl;
• or a substituted or unsubstituted C2-60 heteroaryl containing at least one heteroatom selected from the group consisting of N, O and S, or two adjacent radicals of R1 to R21 are linked to form a substituted or unsubstituted C6-60 aryl, and
• one of R1 to R16 is linked to L3.