Research On Metasurface Of Inorganic Perovskite Controlled By Temperature And Humidity

Metasurface is an artificially designed nanostructure.The cell array on a two-dimensional plane has a thickness ranging from tens of nanometers to hundreds of nanometers.As a two-dimensional metamaterials,metasurface can realize the manipulation,transformation and perception of light on the sub-wavelength scale.Metasurface can integrate more functions on miniaturized devices,which is an ideal way to realize smart terminals.The structural color produced by the microstructure of the metasurface has the characteristics of high saturation,high resolution and permanence,and has a good development space in the field of nano-color printing.However,once the structure of the metasurface is prepared,the structural color is a single static state,which limits the application of structural color.In order to solve this problem,an all-inorganic perovskite film with a variable refractive index was used as the metasurface substrate,and its quality was optimized.The conversion between the two phases of all-inorganic perovskite film was realized and the corresponding refractive index was measured.On this basis,a metasurface model with dynamic control of structural color is designed.Aiming at the problems of poor coverage and low crystallinity of inorganic perovskite films,a scheme of doping different proportions of Li~+into perovskite precursor solution was proposed to improve the quality of the films.Through various characterization tests,the optimal doping of 4%Li~+was determined.The crystal coverage of perovskite film is more than 95%,and the surface roughness is 7.41 nm.Using a closed temperature and humidity control box to control temperature and humidity.Using moisture as the inducing condition for phase change.The color of the film changed from orange-red to transparent colorless.The crystal structure,absorption spectrum,fluorescence spectrum and refractive index were measured to verify the reversibility of the phase change.The light absorption of low temperature phase and high temperature phase at the edge of the band is about 2.9 e V and 2.05 e V.The influence of humidity on the phase transition time and phase transition results is studied,and the optimal phase transition conditions are finally determined.Under room-temperature,with 80%humidity high temperature phase transforms into low temperature phase.Under 280?,with 60%humidity,the low-temperature phase transforms into the high-temperature phase.In order to solve the problem that the structural color generated by the metasurface is statically fixed,perovskite grating structure is designed by using COMSOL.The period,width and thickness of the structure were optimized to achieve a narrow-band high anti-resonant peak spectrum.The half-width is 20 nm,and the peak intensity is as high as 80%.Utilizing the characteristics of the perovskite phase transition,including different phase states have different refractive indexes,different light control ability,this paper realized metasurface produces different structural colors while with the same size.This paper provides a new way for the development and application of dynamic metasurface and optical devices.