Efficient and low roll-off deep-blue organic light-emitting diodes with anthracene-based compounds as hosts

In this work, we synthesized and characterized four bipolar host materials, which were 9-(naphthalen-1-yl)-10-(4-(naphthalen-2-yl)phenyl)anthracene (NA-AN-NA), 1-(4-(10-(naphthalen-1-yl)anthracen-9-yl)phenyl)dibenzo[b,d]furan, 1-(4-(10-phenylanthracen-9-yl)phenyl)dibenzo[b,d]furan, and 2-(4-(10-phenylanthracen-9-yl)phenyl)dibenzo[b,d]furan. These four materials possessed good thermal stability and showed suitable highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels that match the hole and electron transporting layers. Organic light-emitting diodes (OLEDs) were fabricated based on these four hosts and 4,9-diisopropyl-N,N,N′,N′-tetrakis-(4-methyl-biphenyl-3-yl)-pyrene-1,6-diamine (DITBDAP) as a guest in the emitting layer. The OLED based on NA-AN-NA achieved a deep-blue emission centered at 460 nm with the Commission International de L’Eclairage coordinates of (0.1298, 0.1712) and reached a maximum external quantum efficiency of 8.10% and a maximum luminance of 7973 cd m−2. The full width at half maximum of the NA-AN-NA-based OLED was 42 nm. And the current efficiency maintained at 8.71 cd A−1 at 1000 cd m−2, with a low efficiency roll-off of only 2.9%. The results indicate that the strategy of designing a host with balanced hole and electron transporting properties is a practical way to achieve highly efficient and low roll-off deep blue OLEDs.