基于蓝黄磷光二元互补色的高效聚合物白光器件

研究了基于互补色的高效聚合物白光器件,双色材料包括蓝绿光材料双(4,6-二氟苯基吡啶-N,C2)吡啶甲酰合铱(Firpic)和黄光材料三3-(2,6-二甲基苯氧基)-6-(2-噻吩基)-哒嗪]铱(Fs-1),器件结构为ITO/PEDOT(40 nm)/PVK:OXD-7:Firpic:Fs-1(80 nm)/Ba(4 nm)/Al(120 nm).当发光层材料PVK∶OXD-7∶Firpic∶Fs-1质量比为63∶27∶10∶0.25时,用溶液加工方法得到高效白光器件,此时CIE色坐标为(0.30,0.39),最大电流效率为10.8 cd.A-1,亮度可达到4200 cd.m-2.在此基础上,引入水溶性电子注入材料聚9,9-二(3′-N,N-二甲基胺基丙基-2,7-芴-2,7-交-(9,9-二辛基芴)](PFN)修饰阴极界面,使载流子注入和传输更平衡,当阴极为PFN(20 nm)/Al(120 nm)时,电流效率获得显著改善,达到13.1 cd.A-1,此时电流密度为4.9 mA.cm-2,亮度可达到6096 cd.m-2,白光器件的色坐标为(0.33,0.39),同时发光光谱稳定.另外通过电致发光(EL)、光致发光(PL)光谱及能级结构图分析了载流子俘获和能量转移在发光中的作用.

Efficient Polymer White-Light-Emitting Devices Based on Two Complementary Phosphorescent Colors

White polymer light -emitting diodes (WPLEDs) were fabricated by spin coating method using two complementary colors. The device structure used here is ITO/PEDOT (40 nm)/emitting layer (80 nm)/Ba (4 nm)/Al (120 nm). When the mass ratio of PVK:OXD -7:iridium bis(2 -(4,6 -difluorophenyl) -pyridinato -N,C2)picolinate (Firpic):tris(3 -(2,6 -dimethylphenoxy) -6-(thiophen -2-yl)pyridazine)iridium (Fs-1) was 63:27:10:0.25, white light with Commission Internationale deL 'Eclairage (CIE) coordinates of (0.30, 0.39) was obtained. The maximum current efficiency was 10.8 cd·A ^-1 and the maximum brightness was 4200 cd·m ^-2. To improve the hole -electron injection balance and the device 's character, a thin layer of water -soluble electronic transporting material was used to modify the cathode. In this case, efficient white light emission with a maximum current efficiency of 13.1 cd·A^-1 anda maximum brightness of 6069 cd·m^-2 was obtained. Using poly(9,9 -bis(3 '-(N,N-dimethylamino) propyl) -2,7 -fuorene) -alt -2,7 -(9,9 -dioctylfuorene)] (PFN) (20 nm)/Al (120 nm) as the cathode resulted in CIE coordinates of (0.33, 0.39) and the EL spectrum was also found to be quite stable. The effects of charge trapping and energy transfer on device performance were discussed by considering the photoluminescence (PL) and electroluminescence (EL) spectra as well as the energy band diagramof the device.