Organic light emitting device

An organic light emitting device, comprising:

• a first electrode;
• a hole transport region on the first electrode;
• an emission layer on the hole transport region;
• a first buffer layer on the emission layer;
• a second buffer layer on the first buffer layer;
• an electron transport region on the second buffer layer;
• and
• a second electrode on the electron transport region,
• wherein the first buffer layer includes a first buffer compound represented by the following Formula 1 or Formula 2, and the second buffer layer includes a second buffer compound represented by the following Formula 3:
• wherein, in Formulae 1 to 3,
• R1, R2, R3, R4, R5 and R6 are each independently a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having 5 to 30 ring carbon atoms,
• R1, R2, R3, R4, R5 and R6 are separate or adjacent ones thereof combine to form a ring,
• Ar1 is a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having 5 to 30 ring carbon atoms,
• L1 and L2 are each independently a direct linkage, a substituted or unsubstituted arylene group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroarylene group having 4 to 30 ring carbon atoms,
• a is an integer of 0 to 3,
• b is an integer of 0 to 4, and
• n and m are each independently 0 or 1.