Organic light emitting display device (OLED) having p-type charge generation layer (CGL) formed between emissions stack

An organic light witting display device comprising:

• a first emission part including a first hole transport layer, a first emission layer, and a first electron transport layer;
• a second emission part on the first emission part, the second emission part including a second hole transport layer, a second emission layer, and a second electron transport layer, the second hole transport layer comprising a combination of a first material and a second material that have two kinds of characteristics and mixed in the second hole transport layer;
• a third emission part on the second emission part, the third emission part including a third hole transport layer, a third emission layer, and a third electron transport layer;
• a first P-type charge generation layer between the first emission part and the second emission part;
• and
• a second P-type charge generation layer between the second emission part and the third emission part,
• wherein:
• the organic light emitting display device comprises a fourth hole transport layer on the third hole transport layer,
• an absolute value of a highest occupied molecular orbitals (HOMO) energy level of the third hole transport layer and an absolute value of a HOMO energy level of the fourth hole transport layer are equal,
• the first P-type charge generation layer does not include a dopant,
• a thickness of the second hole transport layer is within a range of 5 nm to 10 nm,
• a hole mobility of one of the first material and the second material is higher than a hole mobility of the first P-type charge generation layer,
• a hole mobility of the second material mixed with the first material in the second hole transport layer is within a range of approximately 1×10−2 cm2/Vs to 1×10−4 cm2/Vs, and
• the first and second materials of the second hole transport layer include a starburst amine group.