Reviving Lead Halide Perovskite Quantum Dots By Triallylamine Etching And Its Application For Light-Emitting Diodes

Display and lighting are indispensable technologies in current human society.They not only affect people’s quality of life but promote the development of technology and economy.With the rapid development of advanced display technologies such as virtual reality and augmented reality,the near-eye display has become increasingly demanding in terms of the performance of display devices.Micro-LED is a new display technology with high brightness,high efficiency,wide color gamut,low power consumption,and long life,which is considered an important direction for future display technology.However,micro-LEDs also face some manufacturing and integration challenges,such as high cost,poor uniformity,and low reliability.Because the smaller the light-emitting pixel of perovskite micro-LEDs,the higher their luminescence effect in general,which is contrary to the empirical rule of traditional inorganic micro-LEDs.Perovskite micro-LEDs can solve some of the problems facing the current development of micro-LEDsLead halide perovskite are a class of inorganic or organic-inorganic hybrid semiconductor materials with special ionic crystal structures and excellent optoelectronic properties,which have attracted extensive attention in the fields of display and lighting in recent years.Lead halide perovskite quantum dots has the advantages of a high luminescence effect,wide color gamut,low driving voltage,and simple preparation for application in micro-LEDs.This thesis focuses on the synthesis and reviving technology of Cs Pb Br₃ perovskite quantum dots and explores the feasibility of the revived quantum dots applied in the light-emitting layer of LEDs.The specific content and research results are as follows:（1）The surface of aged Cs Pb Br₃ quantum dots was etched and the surface defect layer was peeled off using triallylamine,which is liquid at room temperature,as an etchant.Therefore,the aged quantum dots re-emit bright green light instantly after etching.Comparison of the optical properties,morphology and structure,and surface chemical state and composition of the fresh,aged,and revived quantum dots reveals the details of quantum dot surface variety.The in-situ photoluminescence-tracking characterization elucidates that the emission peak position of the quantum dots gradually blue-shifted as the etching time increased after adding an appropriate amount of triallylamine to the aged Cs Pb Br₃ quantum dot solution.The results show that the triallylamine etching reduces the size of the aged Cs Pb Br₃ quantum dots,and the emission peak of the quantum dots was at 506 nm with narrow full width at half maximum of 19 nm and photoluminescence quantum yields of 99.8%after etching recovery.（2）Quantum dot LED devices were successfully prepared by rational design of device structure using fresh,aged,and revived Cs Pb Br₃ quantum dots as the light-emitting layer,respectively.The results show that the LEDs equipped with revived quantum dots exhibit a peak external quantum efficiency of 8.0%at a current density of 1.4 m A/cm².The device performance is better than that of LEDs equipped with aged quantum dots and can reach the device performance of LEDs equipped with fresh quantum dots.