GO-induced effective interconnection layer for all solution-processed tandem quantum dot light-emitting diodes

基于PEDOT:PSS-GO/ZnMgO掺杂连接层的溶液加工串联量子点发光二极管

Compared to conventional quantum dot light-emitting diodes,tandem quantum dot light-emitting diodes(TQLEDs)possess higher device efficiency and more applications in the field of flat panel display and solid-state lighting in the future.The TQLED is a multilayer structure device which connects two or more light-emitting units by using an interconnection layer(ICL),which plays an extremely important role in the TQLED.Therefore,realizing an effective ICL is the key to obtain high-efficiency TQLEDs.In this work,the p-type materials polys(3,4-ethylenedioxythiophene),poly(styrenesulfonate)(PEDOT:PSS)and the n-type material zinc magnesium oxide(ZnMgO),were used,and an effective hybrid ICL,the PEDOT:PSS-GO/ZnMgO,was obtained by doping graphene oxide(GO)into PEDOT:PSS.The effect of GO additive on the ICL was systematically investigated.It exhibits that the GO additive brought the fine charge carrier generation and injection capacity simultaneously.Thus,the all solutionprocessed red TQLEDs were prepared and characterized for the first time.The maximum luminance of 40877 cd/m^(2) and the highest current efficiency of 19.6 cd/A were achieved,respectively,showing a 21%growth and a 51%increase when compared with those of the reference device without GO.The encouraging results suggest that our investigation paves the way for efficient all solution-processed TQLEDs.

串联量子点发光二极管(TQLEDs)相较于传统QLEDs而言,在相同的发光亮度下具有更高的器件效率,因而,在未来显示和照明领域中具有极高的应用价值。TQLEDs是利用连接层(ICL)将两个或多个发光单元连接起来的多层结构器件,其中的连接层起着极为重要的作用。因此,实现有效的连接层是获得高效率TQLEDs的关键。为获得高效率溶液加工TQLEDs,本文采用可溶液加工的P型材料聚(3,4-亚乙基二氧噻吩):聚苯乙烯磺酸盐(PEDOT:PSS)和n型材料氧化锌镁(ZnMgO),并在PEDOT:PSS中掺杂无机氧化物-氧化石墨烯(GO)(体积比为5:1),形成PEDOT:PSS-GO/ZnMgO掺杂ICL以增强其在下层有机薄膜上的浸润性,增加了连接层的有效沉积,提高了连接层的载流子注入和产生。利用该ICL制备了溶液加工倒置红光TQLEDs:ITO/ZnO/QDs/PVK/PEDOT:PSS-GO/ZnMgO/QDs/PVK/PEDOT:PSS/Al,其最大发光强度为40877 cd/m^(2),最大电流效率高达19.6 cd/A,相比于未掺杂GO的参考器件(最大亮度为33868 cd/m^(2),最大电流效率为13 cd/A),其发光强度增加了21%,最大电流效率增加了51%。结果表明,无机氧化物掺杂是一种可实现有效ICL的简单且有效的方法,能有效提升溶液加工TQLEDs的性能,进而推动QLEDs的实际生产应用。