Copper Ion Inks Capable of Screen Printing and Intense Pulsed-Light Sintering on PET Substrates

Abstract

A copper ion ink capable of screen printing and intense pulsed-light (IPL) sintering on poly(ethylene terephthalate) (PET) substrates was developed. Using copper nitrate trihydrate as a copper precursor, we prepared this ink with 2butoxyethanol solvent and an ethyl cellulose additive to ensure excellent wettability with PET substrates and screen printability. After screen printing on PET substrates with this transparent ion ink, the printed ink patterns dry quickly at a low temperature of 100 °C, and an excellent electrical resistivity of 5 μΩ•cm was obtained by short IPL sintering of 20 ms. Because of the high boiling point of 2-butoxyethanol used as a solvent, this ink has a very low evaporation rate at room temperature, so it is suitable for screen printing without clogging of the screen mesh. With this ion ink, it was possible to screen-print copper patterns with a line width of 200 μm. We compared screen-printing properties using this copper ion ink with those of silver and copper nanoparticle inks. Nanoparticle inks showed significant spread in the printed patterns during the screen printing, whereas this copper ion ink showed the lowest spread to enable the formation of fine patterns. In addition, it was confirmed that this ion ink had the least damage to the PET substrate during the IPL sintering process compared to other nanoparticle inks. This ink also has a long storage stability over 4 weeks without precipitation or phase separation. The optimal ink composition and process conditions for securing such excellent copper pattern printing characteristics were suggested in this study.

Design, fabrication and applications of flexible RFID antennas based on printed electronic materials and technologies

“…In 2022, Song et al developed a copper ion ink capable of screen printing and IPL sintering. 128 This ink consisted of three components: copper nitrate trihydrate, 2-butoxyethanol, and ethyl cellulose. Due to the high boiling point of 2-butoxyethanol, the as-prepared ink has a very low evaporation rate and is suitable for screen printing without clogging of the screen mesh.…”

“…Fig.9 (a-c) Images of copper patterns screen-printed and sintered using the as-prepared copper ion ink. (d) The antenna pattern image screenprinted on PET substrate with copper ion ink and the image after IPL sintering 128. Reproduced with permission from ref 128…”

Unraveling the Steric Link to Copper Precursor Decomposition: A Multi‐Faceted Study for the Printing of Flexible Electronics

“…[10][11][12] As the third most conductive metal, [13] copper is an attractive choice for use in MOD precursors. [14] The criteria for the suitability of a MOD ink for inkjet printing include its ability to deposit coatings with conductivities comparable to that of the bulk metal at low temperatures (<200 °C), short sintering times, a long shelf life (>6 months), good substrate adhesion, and low environmental impact. [15] There are several reports of MOD formulations that fulfil these criteria; [16][17][18] however, there is little evidence to explain how the ligands or additives used give rise to these desirable properties as well-defined, discrete compounds are rarely isolated.…”

“…[ 10–12 ] As the third most conductive metal, [ 13 ] copper is an attractive choice for use in MOD precursors. [ 14 ] The criteria for the suitability of a MOD ink for inkjet printing include its ability to deposit coatings with conductivities comparable to that of the bulk metal at low temperatures (<200 °C), short sintering times, a long shelf life (>6 months), good substrate adhesion, and low environmental impact. [ 15 ]…”

Development of a Flexible and Wearable Microelectrode Array Patch Using a Screen-Printed Masking Technique for Accelerated Wound Healing

“…Advances in flexible electronics have gone way past conventional photolithography techniques to printing technology. − Screen printing is a very reliable method of fabricating modern flexible sensors because of several advantages like a large area, high yield, lightweightness, and cost-effectiveness along with the ability to tune sensor properties through the use of various inks pertaining to specific applications. − Recently, this technique has also been used to develop miniaturized electrodes for ES applications by various users. Ravichandran et al have developed a customized muscle ES neuro-prosthesis patch to stimulate targeted muscles by screen-printing silver ink as stimulation electrodes over a flexible Ecoflex substrate .…”