The Controllable Preparation Of ZnO Nanoparticles And Their Application In QD-LEDs

In recent years,Quantum Dot Light-Emitting Diodes?QD-LEDs?have been widely used as light-emitting devices.In this thesis,zinc oxide?ZnO?nanoparticles are used as the material of electron transport layer,and core/shell quantum dots?QD?are used as the material of light-emitting layer for research:?1?ZnO nanoparticles are used as the material of electron transport layer for research:At present,a large number of experimental results show that ZnO nanoparticle thin films are one of the best choices for preparing electron transport layer materials of QD-LEDs.Therefore,in order to improve the performance of QD-LEDs,it is highly desirable to prepare ZnO nanoparticles with good dispersibility and particle size controllability.In this thesis,a ligand-assisted method was used:ZnO nanoparticles were prepared by using ethanolamine as a coating agent.This method can not only easily prepare ZnO nanoparticles with good dispersibility,uniform size distribution and size controllability,and the experimental method also has higher reproducibility.Since the addition of ethanolamine can effectively control the nucleation and growth process of ZnO nanoparticles,ethanolamine plays an important role in the preparation of monodisperse ZnO nanoparticles.Moreover,the experimental results show that,compared with the traditional ligand-free method,the ZnO nanoparticles prepared by the method of adding ethanolamine do have good dispersibility and size distribution,and the ligand-assisted method can effectively control the growth size of ZnO nanoparticles.On the other hand,compared with the conventional method without ligand coating,the QD-LEDs with the ZnO nanoparticles prepared by the ligand-assisted method as the material of electron transport layer have higher superiority in electroluminescence and the like.?2?The blue-light QD of the Cd_xZn_1-xS/?ZnS?_y core/shell structure is used as the light-emitting layer material for research:the semiconductor QD has a lot of advantages:narrow full width at half maxima,strong luminescent stability,high color saturation,good color purity,strong monochromaticity.And its size can be adjusted by adjusting the preparation process,so that the luminescent color of QD can be adjusted.Therefore,QD thin films are one of the best choices for preparing luminescent layer materials of QD-LEDs.At current,although the red-light QD and green-light QD can meet most of the requirements of the QD-LEDs light-emitting layer material,the blue-light QD performance is still very low.Since the QD of the simple core structure has a series of disadvantages:a lot of surface defects,the quantum yield is low,the stability is poor and it is difficult to passivate the surface defects by epitaxial growth.Therefore,it is highly desirable to coat the outer layer of the QD of the core structure with a shell.The core/shell structure can effectively reduce the surface defects of the simple core structure QD and improve its stability.In this paper,three kinds of blue-light QDs with different emission wavelengths were prepared by adjusting the preparation process of the core and shell of the Cd_xZn_1-xS/?ZnS?_y core/shell structure QD.