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-4 H -pyran ( DCATP ) and 2,6-bis[4-( N -(4- tert -butylphenyl)- N -(3,5-di- tert -butylphenyl)amino)benzene]vinyl-4-(dicyanomethylene)-4 H -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 6.87 cd/A and 2.70 lm/W, respectively, at 20 mA/cm 2 with the CIE coordinates of (0.48, 0.50) at 7.0 V. In addition, an efficient red organic light-emitting diode using BDCTP as a dopant exhibited a luminous and power efficiency of 2.30 cd/A and 1.31 lm/W, respectively, at 20 mA/cm 2 and CIE coordinates of (0.61, 0.39).