Liquid Crystal Multilayer Structure’s Research And Its Application In The Field Of Particle Fixed-point Assembly

Liquid crystal is a material state between solid and liquid,and has the fluidity of liquid and the anisotropic property of solid.The special properties give it a unique self-assembly capability and response to external fields such as light,electricity,heat and magnetism.Nowadays,with the rapid development of technology,liquid crystal has penetrated every corner of many emerging industries,and has spread throughout the communications industry,flat panel display,laser,radar,optical encryption and many other fields.Nanoparticles have complex and diverse sizes,shapes,chemical properties,and surface functionality.When they are dispersed in a medium,they can aggregate into clusters or form various lattices.At this time,if the distance between particles is controllable,it can be used for potential applications.Among them,perovskite quantum dots have become an emerging hotspot in the field of luminescent materials in recent years due to their excellent photoelectric properties such as spontaneous emission of polarized light and convenient synthesis methods.In recent years,people have paid more and more attention to guiding particle assembly in liquid crystals.In the past examples of liquid crystal guided particle assembly,it is often necessary to modify the liquid crystal and the particles with compatible groups,so the steps are cumbersome and the success rate is low.And the current reports about the perovskite quantum dots guided by the self-assembly properties of the liquid crystal multilayer structure are not common.In this article,first of all,in the second chapter,we summarize the various control methods of the multi-layer structure of each phase of liquid crystal and the novel applications derived therefrom.The structural characteristics and control methods of liquid crystals in the three phase states of smectic phase,cholesteric phase and blue phase are mainly explained.It also lists its development history and frontier progress in the fields of microlens arrays,beam steering,particle manipulation,light field control,etc.,and prospects for the prospects and impact of liquid crystal multilayer structures.In Chapter 3,a convenient method for fixed-point manipulation of perovskite quantum dots Cs Pb Br3 using smectic liquid crystal is designed.Using this method for fixed-point manipulation of quantum dots can avoid the cumbersome steps of modifying particles and liquid crystal in traditional liquid crystal manipulation particle experiments.In this experiment,the photo-oriented alignment layer substrate of the device was first exposed by using light-controlled alignment exposure technology to prepare an alignment film that induces the growth of a liquid crystal multilayer structure.Then use a layer of liquid crystal polymer as a space to stabilize and copy the alignment layer pattern,finally layer coating the particle solution and the liquid crystal heated to the isotropic phase,By repeatedly raising and lowering the temperature,the liquid crystal defect structure is optimized,and finally the liquid crystal defect structure is induced to assemble particles.Combining the selfassembly characteristics of liquid crystal with the photoelectric performance of perovskite quantum dots is expected to provide new ideas for overcoming the technical bottlenecks of various microdisplay devices,such as the massive transfer of Micro-LEDs.