3‐Cyano Imidazopyridine Acceptor‐based Bipolar and n‐type Host Materials for Phosphorescent Organic Light‐Emitting Diodes

다국어 초록 (Multilingual Abstract)

Two host materials named 8‐(3‐(9H‐carbazol‐9‐yl)phenyl)‐2‐phenylimidazo[1,2‐a]pyridine‐3‐carbonitrile (mCzImPy) and 8,8′‐(1,3‐phenylene)bis(2‐phenylimidazo[1,2‐a]pyridine‐3‐carbonitrile) (mBisImPy) were synthesized as a bipolar host and a n‐type host, respectively, from the herocyclic imidazopyridine unit through its 3‐position CN modification. They worked as the hosts of yellow phosphorescent emitter and the mCzImPy host achieved high quantum efficiency of 18.2% in the yellow phosphorescent devices. Therefore, the 3‐cyanoimidazopyridine showed potential as an electron transport unit of host design.
Two novel CN‐substituted imidazopyridine acceptor based host materials namely mCzImPy and mBisImPy were synthesized as bipolar and n‐type host materials for yellow phosphorescent emitter PO‐01 respectively. Bipolar type host material mCzImPy achieved high quantum efficiency (18.2%) than n‐type host material mBisImPy (12.8%). The bipolar design mCzImPy was superior to balance carriers than n‐type molecular design mBisImPy, which is hindering hole transport in the emitting layer.