Controllable molecular configuration for significant improvement of blue OLEDs based on novel twisted anthracene derivatives

• Novel blue fluorescent emitters based on twisted anthracene derivatives were synthesized.
• The efficiency of p-PABPI is three times of m-PABPI for the non-doped electroluminescent devices.
• The performance of blue OLEDs can be significantly improved by tunable molecular configuration.

Two novel twisted anthracene derivatives, 2-(4-(10-(phenanthren-9-yl)anthracen-9-yl)phenyl)-1-phenyl-1H-phenanthro[9,10-d]-imidazole (p-PABPI) and 2-(3-(10-(phenan-thren-9-yl)anthracen-9-yl)phenyl)-1-phenyl-1H-phenanthro-[9,10-d]imidazole (m-PABPI), have been synthesized. Their photophysical and photochemical properties are also investigated systemically. The non-doped fluorescent organic light-emitting diodes are fabricated by using anthracene derivatives as the emitters. The maximum current efficiencies are achieved to be 3.98 and 1.32 cd A−1 and the maximum power efficiencies are 2.80 and 1.14 lm W−1, respectively. The external quantum efficiency maximum (EQEmax) is 3.61% and 1.33% for p-PABPI and m-PABPI. Intriguingly, the efficiencies of p-PABPI are almost three times larger than that of m-PABPI with only the different molecular configuration. The results revealed a new rule of molecular design based on anthracene derivatives for obtaining high performance blue emission materials.