Facile Synthesis of Mildly Oxidized Graphite Inks for Screen‐Printing of Highly Conductive Electrodes

Abstract

Graphene‐derived materials are attractive components in conductive inks for printed and flexible electronics. Here, the authors report a facile and scalable synthesis of mildly oxidized graphite and its formulation into screen‐printable inks. The screen‐printed electrodes exhibit sheet‐resistance below 1 Ω/sq after rolling‐compression, with a compressed film thickness of ≈3 μm and line‐width resolution below 100 μm. The method, described herein, can be used without the need for substrate‐limiting post‐printing treatments, such as high‐temperature annealing, photonic annealing, or chemical reduction. The approach is applicable to any arbitrary and heat‐sensitive substrate, including plastic and paper, and is both highly cost‐effective and suitable for roll‐to‐roll printing of a wide range of devices.

Water-based highly conductive graphene inks for fully printed humidity sensors

“…The highest conductivity of compressed graphene lines was calculated to be 4.23 ± 2 × 10 4 S m −1 (figure S7), which is around 100 times greater than that of the as-printed graphene lines due to the decreased thickness and better graphene flake connections. This electrical conductivity is highly competitive amongst screen-printed conductive patterns on flexible substrates published in the literature (table S1) [21,32,33,35,36,41,42,[45][46][47][48]. Other post-printing process, such as photonic annealing are effective methods to further improve the conductivity [47].…”

Recent Developments of Flexible and Stretchable Electrochemical Biosensors

“…The spatial resolution and electrical performance of printed electrodes hinge on ink formulation. For instance, the ink with a nearly defect-free graphene oxide derivative can be printed to result in high-resolution lines with a width below 100 µm, a thickness of 3 µm, and a sheet-resistance below 1 Ω/sq [119].…”

“…While the ink is on the ridges of the pattern on the printing cylinder in flexography [87,94,95], gravure printing relies on impressing the film into the cavities of the roll where the ink resides ( Figure 4c) [113]. Both these two printing methods are intrinsically robust and can enable large-area manufacturing [113,[119][120][121][122][123][124].…”

Lab‐Made Graphite and Silver Conductive Inks for the Fabrication of Printed Electrodes

“…As a result, there is a growing demand for inks formulated from low‐cost materials that can bridge the gap between metal‐based inks and conjugated polymers in terms of price and performance. A viable option for this purpose is carbon‐based inks, which are generally produced from chemically processed graphite [4].…”