Removing shortcomings of linear molecules to develop high efficiencies deep-blue organic electroluminescent materials

By using molecular twisting and bulky side group substitution, we successfully develop two deep-blue emitters, BiPI-1 and BiPI-2 . These two twisted linear molecules retain the excellent photophysical and electrical properties of planar analogue and remarkably supress redshifts in solid state emission. Especially, BiPI-1 showed deep-blue emission in both solution and solid phase, and high carrier mobilities with μ h > 10 −3 cm 2 V −1 s −1 and μ e > 10 −5 cm 2 V −1 s −1 . Standard blue electroluminescence (color purity: (0.15, 0.08)) and high device efficiency (CE: 4.62 cd A −1 , EQE: 6.18%) were observed in a non-doped OLED of BiPI-1 .