High performance inkjet-printed QLEDs with 18.3% EQE: improving interfacial contact by novel halogen-free binary solvent system  

作　　者：Ming Chen Liming Xie Changting Wei Yuan-Qiu-Qiang Yi Xiaolian Chen Jian Yang Jinyong Zhuang Fushan Li Wenming Su Zheng Cui 

机构地区：[1]Printable Electronics Research Center,Suzhou Institute of Nano-Tech and Nano-Bionics,Chinese Academy of Sciences,Suzhou,215123,China [2]Guangdong Juhua Printed Display Technol Company Ltd.,Guangzhou,510700,China [3]Institute of Optoelectronic Technology,Fuzhou University,Fuzhou,350002,China

出　　处：《Nano Research》2021年第11期4125-4131,共7页纳米研究（英文版）

基　　金：This work was supported by the National Key Research and Development Program of China(No.2016YFB0401600);the National Natural Science Foundation of China(No.U1605244);China Postdoctoral Science Foundation(No.2020M681726).

摘　　要：Poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt(4,4′-(N-(4-butylphenyl))](TFB),one of the most popular and widely used hole-transport layer(HTL)materials,has been successfully applied in high performance spin-coated quantum dots-based light-emitting diodes(QLEDs)due to its suitable energy level and high mobility.However,there are still many challenging issues in inkjet-printed QLED devices when using TFB as HTL.TFB normally suffers from the interlayer mixing and erosion,and low surface energy against the good film formation.Here,a novel environment-friendly binary solvent system was established for formulating quantum dot(QD)inks,which is based on mixing halogen-free alkane solvents of decalin and n-tridecane.The optimum volume ratio for the mixture of decalin and n-tridecane was found to be 7:3,at which a stable ink jetting flow and coffee-ring free QD films could be formed.To research the influence of substrate surface on the formation of inkjet-printed QD films,TFB was annealed at different temperatures,and the optimum annealing temperature was found to enable high quality inkjet-printed QD film.Inkjet-printed red QLED was ultimately manufactured.A maximum 18.3%of external quantum efficiency(EQE)was achieved,reaching 93%of the spin-coated QLED,which is the best reported high efficiency inkjet-printed red QLEDs to date.In addition,the inkjet-printed QLED achieved similar T75 operational lifetime(27 h)as compared to the spin-coated reference QLED(28 h)at 2,000 cd·m−2.This work demonstrated that the novel orthogonal halogen-free alkane co-solvents can improve the interfacial contact and facilitate high-performance inkjet printing QLEDs with high EQE and stability.

关 键 词：quantum dots quantum dots light-emitting diodes(QLEDs) inkjet printing halogen-free inks contact interface 

分 类 号：TN312.8[电子电信—物理电子学]