适用于喷墨打印制备发光二极管的ZnO量子点配体研究  

Study on ZnO quantum dot ligands for inkjet printing of light-emitting diodes

作　　者：宋家宁 毛雨 王俊杰[1] 李丹阳 欧家琦 彭俊彪[1] Song Jia-Ning;Mao Yu;Wang Jun-Jie;Li Dan-Yang;Ou Jia-Qi;Peng Jun-Biao(State Key Laboratory of Luminescent Materials and Devices,South China University of Technology,Guangzhou 510641,China)

机构地区：[1]华南理工大学,发光材料与器件国家重点实验室,广州510641

出　　处：《物理学报》2023年第13期185-195,共11页Acta Physica Sinica

基　　金：广东省重点领域研发计划(批准号:2022B0303010001)资助的课题。

摘　　要：喷墨打印工艺具有无接触、材料利用率高、成本较低,以及可图案化等优势,是制备全彩量子点显示的关键技术.迁移率高、材料稳定性好的ZnO量子点薄膜作为电子传输层一直是制备量子点发光二极管的重要材料.然而,在ZnO薄膜干燥的过程中,存在ZnO量子点团聚的问题,破坏了ZnO薄膜的形貌和厚度均一性,进而劣化了器件的发光性能.通常在ZnO量子点合成后需要加入配体乙醇胺来将其稳定分散.但是研究发现,当ZnO量子点在空气中干燥成膜时,其与乙醇胺配体连接的化学键容易断裂,使ZnO量子点之间发生聚集.同时氧含量随着时间不断上升,表明外界的水氧结合在薄膜表面,进一步加剧了ZnO量子点之间的团聚.通过使用结合更加紧密的乙二胺四乙酸配体可有效地改善该现象,制备出形貌良好、厚度均匀的ZnO薄膜,进而制备出高效稳定的喷墨打印量子点发光二极管.Inkjet printing as a contact-free,high material utilization,low cost,patternable solution processing technology,may become the future color quantum-dot light-emitting diodes(QLED)production of the key technology.However,owing to the existence of the pixel structure of the substrate array,the film prepared by inkjet printing technology is not so smooth and uniform as that by spin coating technology,which affects the luminescence performance of the device.Therefore,it is necessary to study the film forming mechanism and process of inkjet printing.In order to solve the above problems,this paper focuses on the material and process problems of preparing high-quality electronic transport layer ZnO thin films by inkjet printing.From the perspective of ligand,the ZnO quantum dot material,which is an indispensable electron transport layer,is optimized to prepare the thin films with good morphology and stability in air,and the methods to improve the performances of inkjet printing QLED devices are explored.Firstly,the drying process and influence mechanism of ZnO quantum dot ink in air are investigated.As the thickness of ZnO quantum dot film prepared by inkjet printing increases,the film becomes loose and the surface becomes rough with the continuous extension of the time in the air.These changes make the efficiency of the QLED device decrease and the luminous region uneven.The reason for this phenomenon is that after the ZnO quantum dots are printed into the pixel pit,the random Brownian motion of quantum dots will continue in the process of solvent evaporation.In this process,the ligand ethanolamine connected to the surface of ZnO quantum dots will fall off with the movement and cannot play the role in dispersing the quantum dots.Besides,the external water oxygen and carbon dioxide attach to the film.The combination between the two effects makes the ZnO quantum dots aggregate into large particles and the film becomes loose and porous.In this paper,we use ethylenediamine tetraacetic acid(EDTA)as ligand to synthesize ZnO

关 键 词：喷墨打印 粒子团聚 配体脱落过程 量子点发光二极管 

分 类 号：TN312.8[电子电信—物理电子学] TB383.1[一般工业技术—材料科学与工程]