Novel diarylborane-phenanthroimidazole hybrid bipolar host materials for high-performance red, yellow and green electrophosphorescent devices

Two novel bipolar hosts containing phenanthroimidazole and dimesitylborane with para- and meta-linkage have been designed, synthesized and characterized. The appending Mes2B moiety improves the thermal stability, electrochemical stability and carrier injection/transport ability. Within these merit, we have fabricated highly efficient green (66.3 cd A−1, 63.1 lm W−1, 18.2%), yellow (55.2 cd A−1, 66.6 lm W−1, 14.5%) and red (20.1 cd A−1, 20.4 lm W−1, 13.5%) PhOLEDs by using these compounds as host materials. The results indicate that bipolar host p-BPPI and m-BPPI have high potential in fabricating various color OLEDs for displays and lighting applications.104