Organic light emitting device

An organic light-emitting device comprising:

• a first electrode;
• a second electrode;
• and
• at least one organic material layer between the first and second electrodes,
• wherein the at least one organic material layer includes at least one layer selected from the group consisting of a hole transport layer, an auxiliary hole transport layer and a light-emitting layer, and
• wherein the at least one layer comprises at least two types of a compound represented by one of the following Chemical Formula 2, Chemical Formula 3, Chemical Formula 4, and Chemical Formula 5:
• wherein:
• X represents O or S,
• each of R1 and R2 independently represents an aryl group having 6 to 30 carbon atoms, a heteroaryl group having 5 to 30 carbon atoms, an alkyl group having 1 to 15 carbon atoms, a halogen atom, or a deuterium atom,
• each of Ar1 and Ar2 independently represents a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, an alkyl group having 1 to 30 carbon atoms, an alkenyl group having 2 to 30 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, an alkoxyl group having 1 to 30 carbon atoms, or an aryloxy group having 6 to 30 carbon atoms
• a is an integer from 0 to 4, provided that when a is 2 or more, the corresponding R1 is the same as or different from each other, or adjacent corresponding R1s are bonded to each other to form a ring,
• b is an integer from 0 to 3, provided that when b is 2 or more, the corresponding R2 is the same as or different from each other, or adjacent corresponding R2s are bonded to each other to form a ring,
• m is an integer from 1 to 3,
• each of c and d is independently an integer of 0 or 1, and
• m, c and d are selected such that when m is 1, c+d=2, when m is 2, c+d=1, and when m is 3, c+d=0.