A facile process combined with roll-to-roll flexographic printing and electroless deposition to fabricate RFID tag antenna on paper substrates

Abstract

A reliable and low-cost solution-processing procedure to synthesize low-resistivity metal antenna for radio frequency identification (RFID) tags on paper substrates via roll-to-roll printing combined with electroless deposition (ELD) is demonstrated in this paper. The silver precursor ink has good printability and can maintain stable performance for more than 60 days via adding hydroxyethyl cellulose (HEC) and adjusting the ratio of ink components. Through a series of characterizations proved that a copper layer with good crystallinity, uniformity and high purity had been formed on the substrate when the electroless copper plating time was 25 min. In addition, the narrow copper wire of 89 μm can be obtained, while the electrical resistivity was as low as 2.22 μΩ cm. It is proved that the RFID copper layer antenna prepared by flexographic roll-to-roll printing has qualified mechanical properties and excellent impedance matching with the IC chip, and even after 800 bends, the reading distance of the RFID tag can still maintain 96%. It can be concluded that the improved technology can be used to fabricate metal antenna for RFID tags on a paper substrate. Furthermore, these results suggest the great potential of this particle-free precursor ink in the field of large-scale flexible printed electronics.