基于掺杂空穴注入层的高性能全溶液加工量子点发光二极管

High-performance full-solution-processed quantum dot lightemitting diodes with a doped hole injection layer

全溶液加工量子点发光二极管(Quantum Dot Light-Emitting Diodes,QLEDs)在未来显示和照明领域具有极大的潜在应用价值.目前,空穴注入困难导致的空穴和电子注入不平衡仍是阻碍高效全溶液加工QLEDs实现的主要因素.因此,如何降低空穴注入势垒,提高空穴注入效率是制备高效全溶液加工QLEDs需要考虑的首要问题.本文利用氧化石墨烯(Graphene Oxide,GO)掺杂聚(3,4-亚乙基二氧噻吩):聚(苯乙烯磺酸盐)(PEDOT:PSS)(体积比为1:2)作为空穴注入层,通过提高空穴注入层的功函数及其在下层薄膜上的浸润性,制备了高效的全溶液加工倒置型QLEDs:ITO/ZnMgO/QDs/PVK/PEDOT:PSS-GO/Al.其最大的发光强度高达51392 cd/m2,最大的电流效率为7.60 cd/A.相比未掺杂的参考器件,均实现了近1.3倍的增长.同时,我们还利用该方法制备了正置结构器件:ITO/PEDOT:PSS-GO/PVK/QDs/ZnMgO/Al,并与未掺杂的正置结构器件进行了比较,发现掺杂空穴注入层PEDOT:PSS-GO的引入同样可以使全溶液加工的正置QLEDs的性能增强,使其最大发光强度实现了0.29倍的增长.以上结果表明,掺杂空穴注入层PEDOT:PSS-GO的引入可以提高正置和倒置两种结构QLEDs的性能.相比而言,其对全溶液加工倒置QLEDs的影响更为突出.表明这是实现高效倒置结构全溶液加工QLEDs的一种简单、有效的方法.

Full solution-processed quantum dot light-emitting diodes are the potential ones for future flat panel displays and solid state lighting.The imbalance of holes and electrons due to the larger hole injection barrier is still the critical obstacle for full solution-processed quantum dot light-emitting diodes with high performance.Therefore,improving the hole injection level is the first consideration for us.In this paper,we doped graphene oxide into PEDOT:PSS(volume ratio:1:2)to form hole injection layer PEDOT:PSS-GO,and then fabricated the high-efficiency full solution-processed quantum dot lightemitting diodes with inverted architecture:ITO/ZnMgO/QDs/PVK/PEDOT:PSS-GO/Al.The maximum brightness of 51392 cd/m2,and peak current efficiency of 7.60 cd/A were achieved,showing about 1.3 fold improvement compared to the reference ones.Meanwhile,the conventional ones:ITO/PEDOT:PSS-GO/PVK/QDs/ZnMgO/Al,also fabricated by the same mean,exhibited 0.29 fold increase in maximum brightness.The above results demonstrate that the introduction of GO is beneficial for both normal and inverted full solution-processed quantum dot light-emitting diodes,and is a more effective method for high-performance full solution-processed quantum dot light-emitting diode with inverted structure.