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 includes a compound represented by Chemical Formula 1, and
• the electron transport region includes 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;
• a halogen;
• a cyano;
• a nitro:
• an 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,
• R1 and R2 are each independently 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,
• L1, L2, L3, and L4 are each independently a bond;
• or a substituted or unsubstituted C6-60 arylene,
• A is a substituted or unsubstituted naphthylene,
• B is a C6-60 aryl substituted with at least one cyano group;
• or a substituted or unsubstituted C6-60 heteroaryl containing 1 to 3 nitrogen atoms, and
• i, j, k, and l are ach independently 0 or 1.