Organic light emitting device

An organic light emitting device, comprising:

• a first emitting part on an anode, the first emitting part including a first emission layer and a first hole transport layer;
• a second emitting part on the first emitting part, the second emitting part including a second emission layer and a second hole transport layer;
• a third emitting part on the second emitting part, the third emitting part including a third emission layer and a third hole transport layer;
• and
• a cathode on the third emitting part,
• wherein the third emitting part further includes a fourth emission layer which emits light whose color is the same as that of the third emission layer and includes a dopant and a mixed host obtained by mixing at least two hosts for enhancing an emission efficiency, and
• a fourth hole transport layer which is provided on the third hole transport layer and is in contact with the third emission layer, and has a hole mobility which is lower than that of the third hole transport layer so as to prevent an electron transfer.

An organic light emitting device, comprising:

• a first emitting part on an anode, the first emitting part including a first emission layer;
• a second emitting part on the first emitting part, the second emitting part including a second emission layer;
• a third emitting part on the second emitting part, the third emitting part including a third emission layer;
• and
• a cathode on the third emitting part,
• wherein the second emitting part further includes a fourth emission layer provided below the second emission layer, and the third emitting part further includes a fifth emission layer which emits light whose color is the same as that of the third emission layer and is provided on the third emission layer.