绿色磷光微腔有机电致发光器件研究

Study of Green Phosphorescent Microcavity Organic Light-Emitting Devices

使用典型绿色磷光材料Ir(ppy)3作为发光层,DBR和金属Al作为微腔的一对反射镜,制备了结构为Glass/DBR/ITO/Mo O3(1 nm)/Tc Ta(40 nm)/CBP:Ir(ppy)3(40 nm,6%)/TPBI(47 nm)/Li F(1 nm)/Al(80 nm)的绿色磷光微腔有机电致发光器件(MOLED),同时制作了无腔对比OLED器件,研究微腔结构对器件发光性能的影响。发现OLED的电致发光谱(EL)的峰值是510 nm,半峰全宽(FWHM)为70 nm,MOLED的峰值是514 nm,FWHM为35 nm,比OLED窄化了1/2,MOLED的最大亮度、最大电流效率分别为143000 cd/m2和64.4 cd/A,OLED的最大亮度、最大电流效率分别为103000 cd/m2和41.6 cd/A;测试并计算了器件的外量子效率(EQE),MOLED和OLED的最大EQE分别为18.6%和14.3%。结果表明,微腔器件发光性能比无腔器件得到了很大的改善。

Green phosphorescent microcavity organic light-emitting devices （MOLEDs） in a architecture of Glass/DBR/ITO/MoO3（1 nm） /TcTa（40 nm）/ CBP：Ir（ppy）3（40 nm,6%）/TPBI（47 nm）/LiF（1 nm）/Al（80 nm） using typical green phosphorescent Ir（ppy）3 as luminous layer, DBR and Al as a pair of reflector of microcavity are fabricated. For comparison, OLED without cavity is also developed to investigate the effect of microcavity structure on luminescent properties of phosphorescent devices. The peak of electroluminescence （EL） spectrum of OLED is 510 nm, and the full-width at half-maximum （FWHM） is 70 nm. The peak of MOLED is 514 nm and the FWHM is 35 nm.The FWHM of MOLED is reduced by half for the OLED without microcavity. Compared with the EL spectrum of non-cavity OLEDs, the linewidth of MOLED is narrowed. Also, the colour purity of MOLED is improved. For MOLED, the maximum brightness and the maximum current efficiency are 143000 cd/m^2 and 64.4 cd/A, respectively. The maximum brightness and current efficiency of OLED are 103000 cd/m^2 and 41.6 cd/A. The maximum external quantum efficiency （EQE） of the device is tested and calculated, and the maximum EQEs of MOLED and OLED are 18.6% and 14.3% , respectively. The experimental results show that the luminescence properties of microcavity devices are improved greatly compared with that of the no-cavity devices.