Synthesis and characterization of ortho-twisted asymmetric anthracene derivatives for blue organic light emitting diodes (OLEDs)

New ortho-twisted asymmetric anthracene derivatives have been synthesized and characterized. The anthracene derivatives show good thermal stability with high glass transition temperatures and a pure blue emission with a narrow full width at half maximum in a film state (λmax = 454 nm with 71 nm for 2-(2-methylnaphtathalene-1-yl)-9,10-di(naphthalene-2-yl)anthracene and λmax = 445 nm with 60 nm for 2-(biphenyl-2-yl)-9,10-di(naphthalene-2-yl)anthracene). A multi-layered device using 2-(2-methylnaphtathalene-1-yl)-9,10-di(naphthalene-2-yl)anthracene as an emitting material exhibits a maximum quantum efficiency of 3.61% (power efficiency of 2.15 lm/W, current efficiency of 3.55 cd/A) and blue Commission Internationale de l’Eclairage chromaticity coordinates (x = 0.15, y = 0.13). A fabricated device using 2-(biphenyl-2-yl)-9,10-di(naphthalene-2-yl)anthracene as an emitting material exhibits a maximum quantum efficiency of 3.7% (power efficiency of 2.11 lm/W, current efficiency of 3.55 cd/A) and a blue Commission Internationale de l’Eclairage chromaticity coordinates (x = 0.15, y = 0.12).

► Ortho-twisted asymmetric anthracene-derivatives.
► High glass transition temperature and pure blue emission.
► Highly twisted non-coplanar structures.
► A maximum quantum efficiency and color index of MNAn: 3.61 % (x = 0.15, y = 0.13).
► A maximum quantum efficiency and color index of BIPAn: 3.7 % (x = 0.15, y = 0.12).