White organic light-emitting devices using Zn(BTZ)_2 doped with Rubrene as emitting layer

摘要

Zn(BTZ)_2 was synthesized from the complex reaction between zinc acetate dihydrate and 2-(2-hydroxy-phenyl) benzothiazolate. Then Zn(BTZ)_2 was used as main light-emitting material doped with different amounts of fluorescent dye Rubrene and fabricated a series of white organic light emitting devices. The configurations were as follows: ITO/PVK:TPD/Zn(BTZ)_2:Rubrene/Al The doping concentration of Rubrene in Zn(BTZ)_2 was 1.2 percent, 0.12 percent, 0.08 percent and 0.08 percent, respectively. According to the EL spectra and CIE coordinates of the above devices, the optimum doping concentration (0.05 percent, weight percent) had been determined. The steady and bright white light emitting of the device with 0.05 percent doping concentration had been obtained, and the white emission covered a wide range of driving voltage (10 -22.5 V). The CIE coordinates were (x=0.341, y=0.334) at the driving voltage of 20 V, which was very close to the equi-energy point (x=0.333, y=0.333), and the corresponding luminance and external quantum efficiency were 4048 Cd/m~2 and 0.63 percent (4.05 Cd/A), respectively. Lastly, we also discussed the emitting mechanisms of the material and the devices.