Fused-ring compounds with a N–B–N unit for efficient blue OLEDs

Fused-ring compounds containing a N–B–N (NBN) unit have emerged as a class of emitters for organic light-emitting diodes (OLEDs) in recent years. However, despite the success of these compounds in achieving efficient green OLEDs, their application in blue OLEDs has not yet been realized. In this study, two new NBN-containing compounds featuring unsymmetrical molecular structures are designed and synthesized. The structural design endows the compounds with efficient blue emission and narrower emission bandwidths. A blue fluorescent OLED based on one of the compounds exhibits simultaneously a high external quantum efficiency of 4.2% and an excellent Commission Internationale de L'Eclairage (CIE) coordinate of (0.152, 0.096). The impressive performance of the OLED device suggests that with proper molecular designs, NBN-containing compounds possess great potential as excellent blue emitters for OLEDs, and thus merit further investigation and attention.