White organic light-emitting diodes based on benzothiazole derivative

This paper describes the white organic light-emitting diodes (WOLEDs) made from a benzothiazole derivative, N-(4-(benzod]thiazol-2-yl)phenyl)-N-phenylnaphthalen-1-amine (BPNA). The bright yellowish-white emission was obtained from a non-doped triple-layer device: ITO/NPB (40 nm)/BPNA (50 nm)/Alq₃ (40 nm)/LiF/Al. The Commission Internationale de L’Eclairage (CIE) coordinates of the device were (0.24, 0.36) at 10 V. The maximum brightness of the device was 9225 cd/m² at 14.4 V. A current efficiency of 3.08 cd/A, a power efficiency of 1.21 lm/W and an external quantum efficiency of 1.18% at a driving current density of 20 mA/cm² were achieved. WOLED with a DCJTB-doped structure of ITO/TcTa/BPNA/BPNA: DCJTB (0.5%)/BPNA/BCP/Alq₃/LiF/Al was fabricated in comparison with the non-doped device. The device emitted bright white light with the CIE coordinates of (0.33, 0.29) at 10 V and a maximum luminance of 7723 cd/m² at 14.8 V.