Anthracene-based fluorescent emitters for efficient blue organic light-emitting diodes

Highly efficient blue luminescent materials are vital in realizing commercialized organic light-emitting diode (OLED) technology. Herein, two new blue emitters 2,4-diphenyl-6-(10-(pyren-1-yl)anthracen-9-yl)-1,3,5-triazine (D1) and 2-(10-([1,1':3′,1″-terphenyl]-5′-yl)anthracen-9-yl)-4,6-diphenyl-1,3,5-triazine (D2) were designed and synthesized by connecting 2,4,6-triphenyl-1,3,5-triazine (TRZ) moiety with classical luminophores anthracene and pyrene units. Interestingly, abandoning two-dimensional planarized molecular backbone, both emitters exhibit three-dimensional (3D) molecular backbone with large dihedral angles, and thus the frontier molecular orbitals (FMOs) electron clouds are mainly located on the central anthracene unit, the peripheral units can work as effective blocking group in space, extremely restraining the π-π stacking, enhancing the EL performance. More importantly, they exhibited highly efficient electroluminescence (EL) performance with slow efficiency roll-off. Especially, as high as external quantum efficiency (EQE) 4.08% and 4.06%, with CIE coordinates of (0.16, 0.20) and (0.15, 0.12) were achieved for D1 and D2, respectively. At the luminance of 100 and 1000 cd m−2, the EQEs still maintained at 3.41% and 3.05% for D1, 3.63% and 2.66% for D2, exhibiting low efficiency roll-off at high luminance.