热激活延迟荧光OLED稳定性研究

Study on Stability of Thermally Activated Delayed Fluorescent OLED

以双极性材料4,4'-bis(carbazol-9-yl)biphenyl(CBP)为主体,绿色热激活延迟荧光材料(4s,6s)-2,4,5,6-tetra(9H-carbazol-9-yl)isophthalonitrile(4CzIPN)为客体,制备了一种多层有机发光二极管.通过改变4CzIPN的掺杂浓度,研究了掺杂浓度对器件光电性能及稳定性的影响,发现4CzIPN掺杂浓度为12%时器件性能最佳.通过设计正向恒流反向恒压的交流驱动电路并对交流驱动电路参数进行优化,研究了驱动方式对延迟荧光有机发光二极管寿命的影响,揭示了交流驱动参数对延迟荧光器件寿命的影响规律.研究表明,基于热激活延迟荧光的有机发光二极管在使用频率为50 Hz,反向偏压为0 mV,50%占空比的交流驱动时,可获得更高的器件寿命.通过比较直流驱动和交流驱动下相同器件的寿命曲线,发现使用交流驱动时器件寿命是直流驱动时的1.5倍左右.

The Thermally Activated Delayed Fluorescence Organic Light-Emitting Diodes(TADF-OLEDs)was fabricated,using bipolarmaterial 4,4′-bis(carbazol-9-yl)biphenyl(CBP)as host,green fluorescent material(4 s,6 s)-2,4,5,6-tetra(9H-carbazol-9-yl)isophthalonitrile(4CzIPN)as dopant.The device structure was optimized by adjusting concentration of 4CzIPN doped into CBP,then the photoelectric properties and lifetimes of device were studied.The performance of 12%4CzIPN-doped device is the best.To study the influence of driving mode on device lifetime of the TADF-OLEDs,the AC driving circuit of positive constant current reverse constant voltage was designed,and the parameters of the AC driving circuit were optimized and adjusted.Research shows that the TADF-OLED achieved a longer device lifetime under AC driven of frequency of 50 Hz,reverse bias of 0 mV and duty cycle of 50%.By comparing the lifetime curves of the same device driven by DC and AC,it is found that the TADF-OLED lifetime under the AC driving scheme is about 1.5 times longer than that of under the DC driving scheme.