表面技术2025，Vol.54Issue(24)：70-78,9.DOI:10.16490/j.cnki.issn.1001-3660.2025.24.004
飞秒激光还原沉积制备柔性电磁屏蔽金属网栅
Femtosecond Laser Reduction Deposition for Flexible Electromagnetic Shielding Metal Mesh Fabrication
摘要
Abstract
With the rapid development of 5G communication,wearable devices,and military stealth technologies,there is an urgent demand for flexible electromagnetic shielding(EMS)materials that simultaneously exhibit high infrared transparency and robust shielding effectiveness(SE).Conventional solutions,such as indium tin oxide(ITO)coatings and metal nanowires face significant challenges,including high fabrication costs,brittleness,complex post-processing,and poor interfacial adhesion.To address these limitations,the work aims to propose an innovative femtosecond laser reduction deposition(FLRD)technique for fabricating flexible copper(Cu)mesh on polyimide(PI)substrates.This approach integrates nanomaterial-enhanced absorption,precision laser processing,and structural design to achieve synergistic optimization of infrared transparency and electromagnetic shielding performance. The research begins by addressing the shortcomings of existing manufacturing methods,such as photolithography and laser ablation.While photolithography offers high resolution,its multi-step process,material incompatibility,and high cost hinder scalability.Laser ablation,though cost-effective,risks damaging polymer substrates due to excessive thermal effects.In contrast,the FLRD method leverages femtosecond laser pulses(1 035 nm wavelength,305 fs pulse duration)to selectively reduce Cu2+ions in a precursor ink composed of copper nitrate trihydrate,ethylene glycol,and graphene nanosheets.The graphene enhances localized light absorption,enabling precise control over the photothermal reduction process without inducing substrate ablation.Systematic optimization of laser parameters,including peak power density(4.2×108 to 12.8×108 W/cm2),scanning speed(5-60 mm/s),and repetition cycles,ensures the formation of continuous,high-conductivity Cu lines with minimal resistivity(2.25×10-6 Ω·m)and sub-30 μm line width. Key findings demonstrate the exceptional performance of the fabricated Cu mesh.By varying the mesh period(200/400/600 μm),the relative transmittance in the mid-infrared range(2 500-25 000 nm)reaches 73.0%-98.7%,surpassing theoretical predictions due to surface plasmon effects.Concurrently,the EMS performance in the 8-12 GHz frequency band achieves 14-34 dB,with sheet resistance values ranging from 18 to 45 Ω/sq.The interplay between geometric parameters and performance metrics is thoroughly analyzed:smaller mesh periods enhance SE at the expense of transmittance,while larger periods prioritize optical transparency.Remarkably,the Cu/PI interface exhibits outstanding adhesion(ASTM class:5B),and the mesh retains mechanical stability after 10 000 bending cycles(radius:3 mm,angle:150°),with a resistance change rate below 0.56. A scalable and versatile platform is established for manufacturing high-performance infrared-transparent EMS materials.The FLRD technique eliminates the need for vacuum systems,masks,or post-processing,significantly reducing production costs and complexity.By decoupling optical and electrical properties through tunable mesh architectures,the technology offers unprecedented design flexibility for applications in infrared optical windows,flexible electronics,and high-frequency electromagnetic protection.Future work could hybrid nanostructures to further optimize performance across broader spectral ranges.Overall,this research advances the frontier of multifunctional material engineering,providing a viable pathway that meets the escalating demands of next-generation optoelectronic and communication systems.关键词
激光制造/飞秒激光还原沉积技术/红外透明薄膜/电磁屏蔽/金属网栅Key words
laser manufacturing/femtosecond laser reduction deposition/infrared transparent film/electromagnetic shielding/metal mesh分类
通用工业技术引用本文复制引用
黄育欣,崔梦雅,肖荣诗,黄婷..飞秒激光还原沉积制备柔性电磁屏蔽金属网栅[J].表面技术,2025,54(24):70-78,9.基金项目
北京市自然科学基金青年项目(2244087)Beijing Natural Science Foundation Youth Program(2244087) （2244087）
