High efficient near-infrared sintering for electrohydrodynamic printed frequency selective surface
Long Bai, Ziru Wang, Dong Ye, Hanghang Wei, Zihan Peng, Jianping Ge, Siwei Tan, Tianxiang Li, Hao Wu
Abstract
The efficient and compatible nano-silver paste sintering technology is significant for printed electronics. However, the current sintering technology still has limitations in terms of sintering time, post-sintering resistivity, and applicable types of substrates. Here we propose a highly efficient near-infrared sintering method for electrohydrodynamic (EHD) printed nano-silver paste. This method is suitable for sintering of nano-silver ink for large curved circuits manufacturing, achieving excellent film conductivity along with enhancing its interfacial strength. This article focuses on exploring the effects of process parameters such as near-infrared sintering power, time and lap-substrate distance on efficiency and resistivity, and ultimately achieving a rapid sintering of nano-silver paste with a resistivity of 12.8 × 10 − 8 Ω ⋅ m . This method adopted near-infrared sintering to sinter nano-silver ink circuits created by EHD printing, followed by plasma treatment to enhance the interfacial strength up to 5B level. Finally, we have successfully fabricated both planar and curved frequency selective surface (FSS) by the above-mentioned methods. The planar FSS sample presented a shielding capability of 2̃5 dB at resonant frequencies of 6 GHz and 10 GHz, which is quite accordance to the simulation results. This method shows great potential for application in large-scale, high-efficiency printed electronics fabrication. This study introduces a novel near-infrared (NIR) sintering method combined with plasma modification and electrohydrodynamic (EHD) printing. It effectively produces frequency-selective surfaces (FSS) on large curved substrates, achieving low resistivity ( 12.8 × 10 − 6 Ω ⋅ m ), enhanced adhesion, and shielding performance at 6 GHz and 10 GHz, advancing printed electronics. • High-Efficiency Near-Infrared Sintering: The study introduces a near-infrared (NIR) sintering method for electrohydrodynamic (EHD) printed nano-silver paste, achieving a rapid sintering process with a low resistivity of 12.8 × 10 − 8 Ω ⋅ m . This method enhances film conductivity and interfacial strength, making it suitable for large-scale printed electronics. • Scalability for Large-Area Printed Electronics: The combination of electrohydrodynamic printing, plasma modification, and near-infrared sintering enables efficient, large-area manufacturing of curved circuits. This method is highly promising for flexible electronics, conformal antennas, and wearable devices, offering a scalable and reliable solution for next-generation printed electronics. • High interface strength: Plasma surface treatment enhances the adhesion between sintered silver pastes and substrates, achieving 5B level adhesion. This process enables better mechanical bonding, improving the durability and reliability of printed electronic circuits on curved surfaces. • Application in Frequency Selective Surfaces (FSS) : The research successfully fabricates both planar and curved frequency selective surfaces (FSS) using the proposed NIR sintering method. The planar FSS demonstrates a shielding capability of 25 dB at resonant frequencies of 6 GHz and 10 GHz, aligning well with simulation results.