| Flexible transparent electrode(FTE)with embedded metal mesh has a wide range of applications in thin film solar cells,OLED,transparent electromagnetic shielding,flexible electric heating film and other fields.However,low-cost,large-area,and mass-production green manufacture of high-performance FTE with embedded metal mesh still remains great challenge.This paper proposes a new method to achieve non-vacuum,templateless,maskless,plating-free fabrication of high-performance TCF with high-resolution and ultrahigh aspect ratio(AR)embedded silver mesh using electric-field-driven(EFD)microscale 3D printing with metal-glass composite nozzles and UV imprinting processes.This paper mainly analyzes and studys the proposed manufacturing method from four aspects: theoretical analysis,manufacturing process method,process parameter law research and two typical case studies,and then establishes the appropriate process window through experiments.The photoelectric performance,electromagnetic shielding performance and electric heating performance of the manufactured TCF with embedded silver mesh are verified through typical cases.The main work and innovations of the subject are as follows:(1)Based on the EFD microscale 3D printing with metal-glass composite nozzles and UV imprinting technology,a new method for manufacturing TCF with high-resolution and ultrahigh AR embedded silver mesh is proposed.The method has the advantages of simple process,low cost,high efficiency,green pollution,and so on.Through numerical simulation and combining with the existing theoretical research,it is verified that the metal-glass composite nozzle can realize the feasibility of making super-high AR embossed silver mesh.(2)After experimental analysis and research,a suitable process window is established.A hydrophobic layer of PDMS is prepared on the hard substrate as the printing substrate.The single variable method was used to study the influences and laws of printing height,printing voltage,printing speed and printing pressure on the morphology of silver lines when printing multilayer silver mesh,and a 3D printing process window for printing silver mesh with large AR was establish.During the UV imprinting process,the influence and law of the thickness of the photolithography and the UV exposure time on the performance of the TCF with embedded silver mesh were studied,and a suitable process window was established.(3)Manufacture of embossed silver mesh with super large AR.The new method proposed in this paper is used to fabricate high-resolution silver mesh with large AR.Among them,a silver “wall” with a line width of 6.5μm and a height of 130μm and a silver “wall” with a line width of 9.2μm and a height of 260μm have been manufactured by using this technology and optimized process parameters.Embossed silver grids with a printing layer number of 1-24 layers(the area of the silver grid is 40mm×40mm,the period is 1000μm,and the line width is 11μm)are manufactured and their structure,morphology,optical properties,and electrical properties were analysised.The research results show that the structure between the layers of the silver wire is dense.When the number of printing layers is increased from 1 to 24,the light transmittance change value of the silver grid is less than 1%,but the conductivity is greatly improved.The quality factor FOM of the silver mesh with 24 printed layers reached 88194.In addition,the corrosion resistance of the embossed silver mesh is tested,and the results show that the prepared silver mesh has excellent chemical stability.(4)The embossed silver mesh with ultrahigh AR is embedded into the photoresist through the UV embossing process to realize the manufacture of the embedded silver mesh with ultrahigh AR.Through this process,the silver meshes with printing layers of1-24 are respectively embedded into the photoresist.The test results show that the TCFs with embedded silver mesh have good photoelectric properties,mechanical properties and surface roughness.The resistance value changes little before and after the silver meshes are embedded.When the printed layer is 24 layers of silver mesh(period is1000μm,line width is 11μm),the TCFs’ square resistance is 0.15Ω/sq,the light transmittance is 90.02%(wavelength is 550nm),the quality factor FOM reaches 23282.In addition,it has been tested that the TCF with embedded silver mesh has good corrosion resistance and environmental stability.The application potential of TCF with embedded silver mesh is analyzed through typical applications.When the sheet resistance of the TCF is 0.61Ω/sq and the light transmittance is 86.12%,the electromagnetic shielding efficiency can reach more than 20 d B(frequency band is8400-12000MHz),achieving a better shielding effect. |
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