碳酸铯修饰Al作为反射阴极的倒置顶发射OLED器件

摘要

Efficient inverted top-emitting organic light-emitting diode (ITOLED) using a thin Cs2CO3 layer modified Al as the reflective bottom cathode is demonstrated. With tris-(8-hydroxy-quinoline) aluminum ( Alq3) as emitting layer and Mo03/Ag as semitransparent anode, the Al/ Cs2CO3 based ITOLED shows a tune-on voltage of 3. 6 V, luminance efficiency of 9. 8 cd/A and 3.4 lm/W, which are much better than those (4.2 V, 8.6 cd/A, 2.85 Im/W) obtained from Mg: Ag based ITOLED and those (5 V, 5. 5 cd/A, 1. 57 lm/W) obtained from bare Al based ITOLED. Electron-only devices research shows that a stronger electron-injection is obtained from Al/Cs2CO3 than Mg: Ag and Al, which is attributed to the lower work function of Al/Cs2CO3 than Mg: Ag and Al. The good performance of Al/Cs2CO3 based ITOLED is attributed to the efficient electron injection from the Al/Cs2CO3 cathode as well as a microcavity effect.%以Cs2CO3修饰的Al电极作为反射阴极制备了高效倒置顶发射结构有机电致发器件(ITOLED).以八羟基喹啉铝(Alq3)作为发光层、MoO3修饰的Ag为半透明阳极时,器件的开启电压为3.6V,发光效率和功率效率分别达到9.8 cd/A和3.4 lm/W.研究结果表明,Al/Cs2CO3为反射阴极的器件性能明显高于使用 Mg:Ag(4.2 V,8.6 cd/A,2.85 lm/W)和Al(5 V,5.5 cd/A,1.57 lm/W)作为反射阴极的倒置顶发射OLED器件.单电子器件研究结果证明,以Cs2CO3修饰的Al电极功函数明显低于Mg:Ag和Al电极,具有更好的电子注入效果.因此,除去微腔效应外,Al/Cs2CO3为反射电极的ITOLED器件性能的提高主要归因于Al/Cs2CO3阴极的有效电子注入.