Low temperature chemical sintering of inkjet-printed Zn nanoparticles for highly conductive flexible electronic components

Abstract

This study illustrates an innovative way to fabricate inkjet-printed tracks by sequential printing of Zn nanoparticle ink and curing ink for low temperature in situ chemical sintering. Employing chemical curing in place of standard sintering methods leads to the advantages of using flexible substrates that may not withstand the high thermal budgets of the standard methods. A general formulation engineering method is adopted to produce highly concentrated Zn ink which is cured by inkjet printing an over-layer of aqueous acetic acid which is the curing agent. The experimental results reveal that a narrow window of acid concentration of curing ink plays a crucial role in determining the electrical properties of the printed Zn nanoparticles. Highly conductive (~105 S m−1) and mechanically flexible printed Zn features are achieved. In addition, from systematic material characterization, we obtain an understanding of the curing mechanism. Finally, a touch sensor circuit is demonstrated involving all-Zn printed conductive tracks.

Highly Conductive Films by Rapid Photonic Annealing of Inkjet Printable Starch–Graphene Ink

“…The drop spacing affects the uniformity, width, and thickness of the printed patterns and therefore requires careful optimization. [6,14] With increased drop spacing, the ink consumption is minimal. However, it gives rise to thinner films (wet thickness) and non-uniform patterns.…”

“…To obtain stable jetting behavior of the ink droplets from the inkjet nozzles, inks should have their viscosity (η), surface tension (γ), and density (ρ) within suitable ranges for a fixed nozzle size ( d ). [ 6,14 ] Using those physical parameters a series of dimensionless numbers: Reynolds number ( R e ) and Weber number ( W e ) [ 3,6,26,27 ] can be defined as follows: where v is the drop velocity after ejection from the nozzles. Both R e and W e , and therefore jetting behavior, can be optimized by varying the surface tension and viscosity of the formulation.…”

“…[14][15][16][17][18][19][20] Formulating inkjet printable graphene ink is generally challenging since the inkjet printing method requires the ink to have specific range of values for the properties such as flake size, surface energy, viscosity, and density. [6,14] The inks mostly require additional surfactants and binders for stabilization that must be removed after the printing process by post-treatment methods in order to attain the desired properties. Thermal annealing at elevated temperatures for a long duration is usually required to remove the additives and achieve the electrical functionality of the printed graphene films, thus limiting the choice of substrates.…”

“…The inkjet printing of conductive patterns offers a promising methodology in various printed electronics applications, such as energy storage and conversion devices, displays, sensors, and RFID. [1][2][3][4][5][6] This technique offers non-contact, additive, and high-resolution drop-on-demand fabrication ability. In printed electronics industries, the inkjet printable conductive inks are mostly dominated by metallic nanoparticles (Ag, Au, Cu, Ni, etc.).…”

Photo-Sintered Silver Thin Films by a High-Power UV-LED Module for Flexible Electronic Applications

“…For decades, printed electronics technology has been developed with materials like metal nanoparticles ink, non-contact technology like drop-on-demand inkjet technology for printing materials on any substrate, and post-treatment process in order to obtain good properties from materials [1][2][3][4][5][6][7][8]. In particular, a new frontier of printed electronics is to print flexible and stretchable electronic devices for wearable electronics [9][10][11].…”