Synthesis Of Photopolymerized Perovskite Quantum Dots With High Stability And Their Application In Color Micro-LED

In recent years,perovskite quantum dots have attracted much attention in the optoelectronic field due to their excellent optical properties.The advantages of adjustable emission wavelength,narrow half-peak width,high quantum yield and low toxicity make it widely used in semiconductor display devices.Micro-LED,as a new generation of display technology,has the advantages of high luminous efficiency,long life,low energy consumption,high brightness,high color purity and high contrast.However,based on the different systems,the red,green and blue chips cannot be prepared on the same substrate,and the ultra-small size and high integration density make the full color display application of micro-LED a great challenge.Full color display is the key technology for the commercialization of micro-LED.At present,the most promising method reported is to use of quantum dots as the color conversion material on blue light micro-LEDs,which can easily realize full color micro-display at low cost,and is expected to be applied to new displays such as augmented reality and virtual reality.However,the poor tolerance of perovskite quantum dots to water,oxygen,light and heat makes them very easy to decompose.The ionic crystal characteristics and low formation energy of quantum dots can lead to more defects,which seriously affects the reliability of quantum dots.In this thesis,the flip-chip blue micro-LEDs is fabricated on the sapphire substrate,a simple way to improve the photoluminescence quantum yields（PLQY）and stability of perovskite Cs Pb Br₃ quantum dots by introducing a light-guiding ligand is established,and patterned it by photolithography,which is expected to be applied to the colorization of micro-displays.The research contents are as follows:1.A 0.63-inch flip-chip blue-light micro-LED chip was fabricated through semiconductor manufacturing processes such as photoresist spin-coating,film deposition,photolithography,dry etching,substrate lift-off,wire-bonding and packaging,and its performance was characterized and analyzed.The pixel size of the blue light micro-LED is 60μm×60μm.160×90 resolution,pixel density is 437PPI.At the driving voltage of 2.70 V,the brightness can reach 1300 cd/m²,with good photoelectric characteristics.2.The perovskite quantum dots with high efficiency and high stability were synthesized by introducing the phenyl phosphorous dioxide photosensitive ligand and using the thermal injection method.The results show that this method can make the photoluminescence quantum yields of Cs Pb Br₃ quantum dots reach 99%,the fluorescence lifetime is 30 ns.They are stable in water for more than 40 hours;The photoluminescence quantum yields and fluorescence lifetime of Cs Pb I₃ quantum dots can reach 81%and 64 ns respectively,and they can remain stable in the air for 6months without losing fluorescence.3.Patterned perovskite quantum dot films.The perovskite quantum dot film are patterned by micro-pore filling method,screen printing method,direct lithography method and plasma treatment method,so that they can be applied to the color of micro-display.The minimum size reached is 40μm for a two-color display,which provides a reference for the application of quantum dots on micro-LED.Finally,a three-color integrated optical architecture is designed to further explore the full-color micro-display scheme,and optical simulation is performed using Light Tools.