Research On Preparation Of High Quality Polyaliline Film And Its Metasurface With Tunable Structural Color

With the increasing demand for new display technologies in today's society,structural colors have unique advantages due to their high saturation,high brightness,wide color gamut,resistance to fading,and low radiation.Therefore,they have also received continuous attention from scientific research and industry..The use of materials with variable refractive index to construct metasurface structures is an important way to realize the application of dynamically tunable structural color.Polyaniline,as an electrochromic material with variable refractive index through electrochemical modulation,has a broad prospect in this field due to its excellent environmental stability,rapid state transition,low cost and good cycle reversibility.However,there are few reports about the preparation process of high-quality polyaniline film that meets the requirements of metasurface design and micro/nano processing.Thus,it is necessary to explore a feasible path.In addition,in order to realize the tunable structural color,it is also significant to design and explore the appropriate model of combining polyaniline with the metasurface.In view of the lack of high-quality polyaniline film preparation technology that meets the requirements of micro/nano processing design and preparation,this article starts with gold and ITO conductive glass as the substrate,and uses capillary in-situ tablet growth method to directly prepare polyaniline film.Then various influential factors such as film thickness,surface roughness and micro-morphology are explored.According to the characterization results,the film was optimized.Finally the preparation process is chosen as carrying out the growth reaction for 270 s on the hydrophilic treated gold substrate in the mixed solution reaction system of 0.1mol/L ANI+1 mol/L H₂SO₄+0.5 mol/L APS.The thickness is controlled at 70?75nm,and the surface roughness is reduced to 6.54 nm.On the 13 nm thick ITO substrate,the thickness of the film obtained is 25?35 nm under 0.3 mol/L ANI+1 mol/L H₂SO₄+0.5 mol/L APS reaction system.And the surface roughness is 5.15 nm.In addition,the refractive index curves of three polyaniline films were measured,and the conductive state n=1.07?1.6,k=0.1?0.62.The highest transmission intensity of the film can reach about 80%,and it has good electrochromic and reversibility through electrochemical regulation and cyclic voltammetry test experiments.There are currently few reports on polyaniline-based metasurface models.This article uses COMSOL and FDTD software to design several model s of polyaniline-based electronically tunable structural color metasurface,including Au disk-PANI-Au metasurface,ITO-silicon(single crystal silicon/amorphous silicon)-PANI metasurface and ITO-Ti O₂-PANI metasurface.Their respective modulating effects of structural color were discussed and analyzed.The designed 13 nm ITO-monocrystalline silicon-PANI metasurface model can obtain high brightness(up to 70%)and high saturation(up to 80%)structural color effects covering purple to red,and its dynamic control effect is obvious.According to the designed ITO-Ti O₂-PANI metasurface model,the appropriate micro/nano process was explored to prepare several samples.And the optical characterization results show that the measured reflectance spectrum is basically consistent with the results obtained by the simulation calculation.