The Preparation And Optoelectronic Properties Of Liquid Crystal Cell With Metal Nanoparticles Array

In recent years,the special properties of nanomaterials have attracted widespread attention at home and abroad.The effect of spatially dimensional changes of metal nanomaterials on its electrical and optical properties more is a hotspot to research at present especially.Periodic array of metal nanomaterials structure can be used in areas such as liquid crystal display(LCD),polarization beam splitter,subwavelength grating and many other fields,and play an important role on development of optoelectronic devices industry.So far there are a lot of method of preparation of metal nanomaterials array,such as chemical deposition and chemical etching preparation method.But the factors which restrict these methods are,such as concentration of reagents,reaction temperature and deposition time and so on.These factors lead to a poor controllability,uneven distribution of particles on surface,uncontrolled structure,impacting on morphology of deposited film on surface eventually.There also is offset printing which can prepares periodic metal nanoarrays structure and control it's surface topography and parameters such as size,shape,and spacing of nanoparticles,however,it is complex,high cost and difficult to use.We introduce a laser optical directional assembly system which can prepare metal nanoarrays with properties of polarization configuration structure,small particle clearance,uniform distribution and alignment,connected hardly with the upper surface of the prism,to ensure the structure stability,reliability and repeatability better.Silver nanoparticles linear array prepared by this system has property of subwavelength metallic grating array,such as polarization characteristics and scattering characteristics.And the structure of suitable size also can undertake alignment of liquid crystal molecules.So our structure can be combined with liquid crystal to assembly into a liquid crystal cell with a metal nanoparticles array.The purpose of this thesis research:Preparing silver nanoparticles linear array with nice morphology and structure by the laser optical directional assembly system,and analyzes the mechanism of polarization characteristics,and then to study the alignment of the array structure on the liquid crystal molecules.In this paper,the main research methods are as follows:1.Analyzing the feasibility of depositing silver nanoparticles linear array by evanescent standing wave field theoretically.Firstly raising the concept and the mechanism of evanescent standing wave field,and the difference of evanescent standing wave field formed by s polarized light and p polarized light.And then we decide the polarization of incident light.Moreover,to obtain the polarization of silver nanoparticles in evanescent standing wave field through formula derivation and simulation calculation and magnitude and distribution of light field force stressing silver nanoparticles.Then analyzing thermodynamics and dynamics stability of silver nanoparticles colloidal solution respectively.It is concluded that it has a strong stability of thermodynamics and dynamics.Analyzing the force of silver nanoparticles stressed expect light field force in evanescent standing wave field,such as molecular inter-atomic forces and the force between dipole finally.2.We can obtain the experiment scheme on the basis of theoretical analysis,and then build optical directional assembly system and prepare silver nanoparticles linear array,after that test optical properties of array.We will introduce the structure of system and the experimental parameters in detail during building the system,and the preparation of silver nanoparticles linear arrays was characterized,at last silver nanoparticles linear array was tested reflection and scattering,we explain the mechanism of polarization property.3.We research the optical properties of LC cell with silver nanoparticles linear array structure.Silver nanoparticles linear array was prepared on ITO thin film coating optical glass prism surface by optical directional assembly system successfully,and then assembly liquid crystal cell with silver nanoparticles linear array.We analyze the principle of effect of silver nanoparticles linear array on liquid crystal molecules in polarization property of liquid crystal cell and theoretical level finally.