T-Butyl group-substituted triphenylamine-containing orange-red fluorescent emitters for organic light-emitting diodes

Abstract

Efficient orange-red fluorescent compounds, 4-(dicyanomethylene)-2-adamantyl-6-(4-(N-(4-tert-butylphenyl)-N-(3,5-di-tert-butylphenyl)amino)benzene)vinyl-4H-pyran (DCATP) and 2,6-bis[4-(N-(4-tert-butylphenyl)-N-(3,5-di-tert-butylphenyl)amino)benzene]vinyl-4-(dicyanomethylene)-4H-pyran (BDCTP) containing the tert-butylated triphenylamine in donor moieties, were synthesized and characterized. In these red emitters, bulky groups, such as t-butyl group and adamantane were introduced to increase the steric hindrance between the red emitters. In particular, an efficient orange-red device containing the emitter DCATP as a dopant showed a luminous and power efficiency of 6.87cd/A and 2.70lm/W, respectively, at 20mA/cm2 with the CIE coordinates of (0.48, 0.50) at 7.0V. In addition, an efficient red organic light-emitting diode using BDCTP as a dopant exhibited a luminous and power efficiency of 2.30cd/A and 1.31lm/W, respectively, at 20mA/cm2 and CIE coordinates of (0.61, 0.39).