Improving hole injection to get better charge balance is a critical issue for achieving high performance quantum dot light-emitting diodes (QLEDs) because the hole injection is generally more difficult than the electron injection in QLEDs. In this work, we report an effort to develop a useful and easy processing bilayer hole injection layer (HIL) that consists of UV-ozone-treated graphene oxide (partially reduced graphene oxide, rGO) and PEDOT:PSS. We have successfully demonstrated that such a hybrid bilayer HIL possesses the advantages of high conductivity, staircase energy-level alignment, and high quality interface contact, which effectively promotes hole injection efficiency in the solution-processed QLEDs. Highly efficient and bright red solution-processed QLEDs have been realized based on the rGO/PEDOT:PSS bilayer stepwise HIL, exhibiting maximum brightness of 89157 cd m^-2, current efficiency of 25.0 cd A^-1 and power efficiency of 10.9 lm W^-1, respectively. Importantly, both high external quantum efficiency (EQE) (>10%) and brightness (>30000 cd m^-2) have been attained simultaneously; the peak EQE of the QLEDs reached 17.3% with a brightness of ∼60108 cd m^-2, showing a great potential for high-power lighting applications.

改善空穴注入以获得更好的电荷平衡是实现高性能量子点发光二极管（QLED）的关键问题，因为空穴注入通常比QLED中的电子注入困难。在这项工作中，我们报告了开发一种有用且易于处理的双层空穴注入层（HIL）的努力，该层由紫外线臭氧处理的氧化石墨烯（部分还原的氧化石墨烯，rGO）和PEDOT：PSS组成。我们已经成功地证明了这种混合双层HIL具有高电导率，阶梯能级对准和高质量界面接触的优点，从而有效地提高了固溶QLED的空穴注入效率。基于rGO / PEDOT：PSS双层逐步HIL，已经实现了高效率和鲜红色溶液处理的QLED，^-2，电流效率分别为25.0 cd A ^-1和功率效率为10.9 lm W ^-1。重要的是，同时达到了高外部量子效率（EQE）（> 10％）和亮度（> 30000 cd m ^-2）；QLED的峰值EQE达到17.3％，亮度约为60108 cd m ^-2，显示出在大功率照明应用中的巨大潜力。