| With many advantages such as high brightness,wide color gamut,long life,and high color purity,Quantum Dot Light Emitting Diodes(QLEDs)with Quantum Dots as the core light emitting material will become a favorable competitor for the new generation of display technology.As the research progresses,the performance of QLEDs devices in all aspects has been steadily developed.In the face of its application needs in the future display field,low-cost,large-area,high-resolution trichromatic integration and QLEDs device construction is one of the important problems that need to be solved.Lithography can achieve ultra-high resolution,and it is an efficient and low-cost large-area array fabrication technology,which provides a feasible method for constructing quantum dot array structures.The thickness and uniformity control of large area of photoresist are the key factors affecting the subsequent structure regularity.Liquid bridge method is an effective technique for preparing large-area thin film,which can accurately control the thickness of thin film.Therefore,it is an effective means to construct large-area high resolution QLEDs by preparing large-area uniform and controllable photoresist thin film by liquid-bridge method,then using lithography technology to prepare high-resolution array structures,and printing quantum dot thin film by liquid-bridge method on the basis of array structures,and forming quantum dot array structures.Based on the above background and ideas,this thesis printed a large-area uniform photoresist film with precisely controllable thickness,studied the deposition morphology of quantum dots in pixel pits of different sizes,and obtained large-area high-resolution quantum dot array structures,based on which multicolor quantum dot composite array structures were prepared by multiple lithography and printing processes,and successfully constructed QLEDs devices.A new idea for the construction of large-area,high-resolution QLEDs based on lithography-assisted device construction.The specific research in this thesis is as follows:(1)Based on the group’s improved two-dimensional liquid bridge device,the photoresist film is printed and prepared close to the thickness of the QLEDs device,which is conducive to uniform luminescence of the pixel dots;and the thickness of the photoresist can be regulated by multiple printing,and a photoresist film with an area of 15×15 cm~2 has been prepared.The high-resolution monochromatic quantum dot array structure was prepared by direct writing lithography and liquid bridge method,and further constructed an arrayed QLEDs light-emitting display device in red,green and blue with the resolution of up to 6937 ppi.And the device performance is as follows:red maximum luminance is 11180 cd/m~2 and external quantum efficiency is 9.67%,green maximum luminance is 47840 cd/m~2 and external quantum efficiency is 8.09%,blue maximum luminance is 1201 cd/m~2 and external quantum efficiency is 7.17%.Then an array of QLEDs with a pixel size of 2×12μm~2 and an area of 1.5×1.5 cm~2 was successfully fabricated with a resolution of1100 ppi.(2)In the previous chapter,the preparation of monochromatic quantum dot array structures and the construction of QLEDs light-emitting display devices were achieved.Based on this,the third chapter achieves the preparation of multi-colour arrayed templates by multiple photolithography and the deposition of quantum dot film of different colours by the liquid bridge method.Finally,two-colour and three-colour quantum dot array structures were prepared with a maximum resolution of 995 ppi and 1847 ppi,respectively.And on this basis,further construction of multi-colour QLEDs devices to obtain partially two-colour electroluminescent displays,which provides a new idea and way of constructing low-cost,large-area,high-resolution full-colour QLEDs devices. |
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