1.4 µm-Thick Transparent Radio Frequency Transmission Lines Based on Instant Fusion of Polyethylene Terephthalate Through Surface of Ag Nanowires
Though a percolated network of silver nanowires (AgNWs) has been considered the most promising flexible transparent electrode because of it high conductivity, high transmittance, and excellent flexibility, fabrication of AgNW-based transmission lines designed to conduct high frequency signals has been scarcely reported. The fabrication and performance of extremely thin (1.4 µm thick) and low lossy (smaller than − 17 dB for reflection coefficient corresponding to 2.5 GHz) transmission lines with unprecedented transparency (higher than 90% for the entire visible light spectrum) are demonstrated in this study. AgNWs deposited onto a 1.4 µm-thick polyethylene terephthalate (PET) sheet were irradiated by intense-pulsed-light to selectively raise their temperature. The intensive photon energy delivered to the AgNWs simultaneously caused the active diffusion of Ag atoms and plasmonic welding, resulting in large drops in resistivity without drastic changes in their physical shape or the optical transmittance of the films. Furthermore, absorption of heat also thermally activated the underlying polymer and causing it to react with the surface of the AgNWs—this results in enhanced adhesion between the AgNWs and the PET. Measurements and simulation of specially designed coplanar waveguide circuits revealed that the fabricated electrode could simultaneously provide excellent transmission characteristics and mechanical stability and transparency.
KeywordsFlash light Photoinduced Ag nanowires Radio frequency Transmission circuits
This work was supported by a National Research Foundation of Korea (NRF) grant [number 2015R1A4A1042417] funded by the Korean government (MSIP). Further support was also provided by the Ministry of Trade, Industry and Energy, Republic of Korea [grant number N0002310] and the Korea Institute of Industrial Technology as “Characteristics of VO2 Nanoink and Intense Pulsed Light Low-Temperature Sintering for Flexible Smart Window Films Using Direct Printing Technology [kitech EO-17-0026]”.
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