Luminance materials containing carbazole and triphenylamine exhibiting high hole-transporting properties

Two novel 2-substitutd-8-hydroxyquinoline derivatives were designed and synthesized. Their luminance properties and carrier transporting abilities were studied when integrated in four different organic light-emitting device structures. The four devices are structured as following—device A: indium tin oxide glass substrate (ITO)/2-TNATA/NPB/(2-[2-(9-ethyl-9H-carbazol-2-yl)-vinyl]-quinolato zinc (1) and 2-[2-(4-diphenylamino-phenyl)-vinyl]-quinolato zinc (2))/Alq₃/LiF/aluminum (Al); device B: ITO/2-TNATA/NPB/1 or 2/LiF/Al; device C: ITO/2-TNATA/1 or 2/Alq₃/LiF/Al; device D: ITO/2-TNATA/1 or 2/Alq₃/LiF/Al. In the device A, the maximum brightness of compound 1 is 5857 cd m⁻² at 11 V with the luminance efficiency 1.84 cd A⁻¹. For 2 it is 6047 cd m⁻² at 10 V with an efficiency of 2.22 cd A⁻¹. In the device B, the maximum brightness of 1 is 745 cd m⁻² at 11 V and efficiency is 0.32 cd A⁻¹. These values are 1748 cd m⁻² at 10 V and 0.42 cd A⁻¹ for 2, respectively. In the device C, the maximum brightness of 1 and 2 are 8729 and 5838 cd m⁻² at 10 V, respectively, with an efficiency of 1.99 and 1.71 cd A⁻¹. In the device D, the maximum brightness and efficiency of 1 are 8512 cd m⁻² at 13 V and 3.10 cd A⁻¹, and they are 9818 cd m⁻² at 13 V and 0.42 cd A⁻¹, for 2. Our results also show that both 1 and 2 are good bipolar and bifunctional molecules with high hole-transporting and luminance properties.