Ink-jet fabrication of electronic components

Abstract

Nanosized metallic particles dispersed in a polymeric matrix have been used conventionally as a paste or ink to print electrically active patterns on different substrates. The potential of ink-jet printing in this field is clearly important but the challenge to date has been how to achieve prints of low volume resistivity from the very low viscosity ink required for ink-jet printing. In this study, ink-jet printing techniques were used to directly deposit metallic conductive patterns to produce wiring boards, antennas, electrodes and so forth. In these methods, aqueous solutions of metal salt and reducing agent were ink-jet printed consecutively onto the substrate, where an immediate chemical reduction transformed the metal cations into very fine metallic particles. The best performing reducing agent for ink-jet metal deposition was found to be ascorbic acid at neutral pH. Using this chemistry, nanosized silver patterns, composed of particles in the size range 10-200 nm, were successfully formed using a standard office ink-jet thermal-head printer. Deposited layers of silver with high electrical conductance up to 1.89 × 10 5 S m −1 and sheet resistance up to 0.5 / were printed whilst higher conductivities might be expected using more appropriate devices.

Integration of additive manufacturing and inkjet printed electronics: a potential route to parts with embedded multifunctionality

“…The phase change typically takes the form of evaporation of carrier solvent [38-40, 44, 54, 60, 67], although can also be via solidification [47,51,56], or gelation [68,69]. Depending upon the ink system used, it may subsequently be necessary to perform further processing to achieve the desired functionality, such as thermal treatment [44,[70][71][72], electromagnetic irradiation [73][74][75], or chemical treatment [76][77][78][79][80][81].…”

“…The use of chemical agents to remove any stabilising agent from the metal has also been investigated, both for MOD inks [76][77][78] and for NP inks [79][80][81]. The use of chemical agents reduces or potentially eliminates the need for any thermal treatment that may be detrimental to polymer substrates ( Figure 5).…”

“…In the case of MOD inks, hydroquinone was used as a reducing agent after brief exposure to UV radiation to reduce the silver ion of deposited silver neodecanoate to atomic silver, with conductivities found to be in the region of~10% that of bulk silver [76]. Other examples of chemical reduction include the use of silver nitrate with ascorbic acid [77], and a silver ammonia solution reduced by formaldehyde [78]. Chemical sintering has also been used with NP inks, where silver nanoparticles treated with solutions containing chloride ions have been found to result in conductivities approaching that of bulk silver [79][80][81].…”

3D Printing of NinjaFlex Filament onto PEDOT:PSS-Coated Textile Fabrics for Electroluminescence Applications

“…Electrical conductivity can be applied onto textile materials through various methods such as screen printing, 32 coating, 33 and inkjet printing. 34 Among these, the coating process has been widely used not only for its easy application but also because coated textiles can be used in various applications such as sensors, data transfer, data monitoring, corrosion protection, and electromagnetic interface (EMI) shielding. 33 Moreover, textile coating has been used for producing flexible, lightweight, and stretchable functional textiles.…”

Inkjet catalyst printing and electroless copper deposition for low-cost patterned microwave passive devices on paper

“…[1,3,10,15,16] Except for the case of gold, such thermal treatments in air can result in significant oxidation of the metallic nanoparticles, particularly for relatively inexpensive non-noble metals, such as copper. [1,[17][18][19][20][21][22][23] While inert or reducing gas atmospheres could be used to minimize or avoid such oxidation, processes that avoid such inert gas thermal treatments would be preferred for scalable manufacturing.…”