Drop-on-demand printing of edge-enhanced and conductive graphene twin-lines by coalescence regulation and multi-layers overwriting

Abstract

Fabrication of straight and highly conductive graphene lines, the cornerstones of high-performance graphene-based printed electronics, still faces considerable challenges. We have developed a convenient and effective way to print edge-enhanced highly conductive graphene twin-lines by coalescence regulation and multi-layers overwriting (CRMO), which enhances both outline accuracy and electrical conductivity. The overlapping traces and wavy edges were eliminated by droplets coalescence at the expense of introducing discrete footprints, which were transformed into continuous lines by multi-layers overwriting. We successfully fabricated the edge-enhanced graphene twin-line with an edge width of 72.33 ± 7.96 μm and a linear resistivity of 0.188 ± 0.160 kΩ μm−1, yielding the coinstantaneous enhancement of outline accuracy, printing efficiency, and electrical conductivity. Printed graphene twin-lines achieve one of the lowest relative linear resistivity reported so far and a conductivity of 359.88 S m−1. We attributed the highly concentrated and tightly interconnected graphene flakes at the edge to the synergetic effect of CRMO. Finally, we have demonstrated the feasibility of CRMO by printing graphene line resistors with excellent linearity and broad resistance ranges. Such findings establish relationships among the printing method, line morphologies, flakes distribution, and electrical conductivity. This work will be of great significance for the self-assembly of graphene-based functional materials and graphene-based printed electronics development.

Direct Fabrication of Micron-Thickness PVA-CNT Patterned Films by Integrating Micro-Pen Writing of PVA Films and Drop-on-Demand Printing of CNT Micropatterns

“…A self-developed uniform nano-carbon droplet printing equipment [ 30 , 34 ] was used for printing the CNT micropatterns, as shown in Figure S2 (see Supplementary Materials ). The CNT droplets could be stably ejected without satellite droplets ( Figure 1 c) with the appropriate pulse amplitude and pulse width.…”

In-situ graphene oxide reduction via inkjet printing using natural reducing inks

“…Graphene oxide (GO) is becoming extremely popular considering its ability to form a homogenous dispersion in water and its capacity to be synthesised in large quantities by modified Hummer's methods [12,13]. Hence, producing huge amounts of highly stable water-based ink is possible by using GO nanosheets [14,15].…”

Three-Dimensional Morphology and Contour Quality of Conductive Lines Printed by High-Viscosity Paste Jetting

“…14 The good liquidity makes the jetting process more stable and controllable, leading to good regularity and consistency of the droplets and printed lines. 15 Despite the many advantages, the viscosity limitation of inkjet printing severely restricts the range of available materials. Materials with good electrical conductivity typically exhibit higher viscosities; therefore, the printing methods of highviscosity materials have become one of the focal points in the field of circuit printing.…”

“…To ensure the printing accuracy of the manufactured part, the deposition morphology of a single droplet in inkjet printing requires good shape and size uniformity. , Simultaneously, the printed lines formed by the coalescence of multiple droplets must exhibit regularity morphology and excellent contour quality. − The raw materials used in inkjet printing technology have low viscosities that are usually less than 200 mPa·s, with values such as 110.7 mPa·s, 17.2 mPa·s, and 34 mPa·s . The good liquidity makes the jetting process more stable and controllable, leading to good regularity and consistency of the droplets and printed lines …”