P‐175: High Triplet Energy Exciplex Forming Hole Type Host for High Performance in Deep‐blue Phosphorescent Organic Light‐emitting Diodes

We designed and synthesized hole type host, N,N‐bis(4‐(tert‐butyl)phenyl)‐3,5‐bis(3,6‐di‐tert‐butyl‐9H‐carbazol‐9‐yl)aniline (t‐DCDPA) to use as an exciplex host with 2,8‐bis(4,6‐diphenyl‐1,3,5‐triazin‐2‐yl)dibenzo[b,d]furan (DBFTrz) electron type host material in deep‐blue phosphorescent organic light‐emitting diodes (PhOLEDs). To evaluate ability of t‐DCDPA, other hole type host materials were used as reference materials, which are tris(4‐(9H‐carbazol‐9‐yl)phenyl)amine (TCTA) and 3,5‐di(9H‐carbazol‐9‐yl)‐N,N‐diphenylaniline (DCDPA). Three pairs showed red‐shifted emission compared to that of each host emission, which means that they formed exciplex. t‐DCDPA:DBFTrz pair showed triplet energy of 2.94 eV, which is similar to that of DCDPA:DBFTrz pair (2.95 eV) and higher than TCTA:DBFTrz (2.83 eV). In deep‐blue PhOLEDs, t‐DCDPA:DBFTrz host pair showed the highest performance among three pairs, which proved that the newly synthesized host is efficient in deep‐blue PhOLEDs.