One-pot ball-milling preparation of graphene/carbon black aqueous inks for highly conductive and flexible printed electronics

Abstract

Stable aqueous carbon inks, with graphene sheets (GSs) and carbon black (CB) as conductive fillers, are prepared by a simple one-pot ball-milling method. The as-prepared composite ink with 10 wt% GSs shows optimized rheological properties (viscosity and thixotropy) for screen printing. The as-printed coatings based on the above ink are uniform and dense on a polyimide substrate, and exhibit a sandwich-type conductive three dimensional network at the microscale. The resistivity of the typical composite coating is as low as 0.23±0.01 Ω cm (92±4 Ω sq⁻¹, 25 µm), which is 30% as that of a pure CB coating (0.77±0.01 Ω cm). It is noteworthy that the resistivity decreases to 0.18±0.01 Ω cm (72±4 Ω sq⁻¹, 25 µm) after a further rolling compression. The coating exhibits good mechanical flexibility, and the resistance slightly increases by 12% after 3000 bending cycles. With the CB/GSs composite coatings as a flexible conductor, fascinating luminescent bookmarks and membrane switches were fabricated, demonstrating the tremendous potential of these coatings in the commercial production of flexible electronics and devices.

摘要

本文以石墨烯和炭黑作为导电填料, 通过一步球磨法制备了高导电的水性碳系油墨. 当石墨烯质量分数为10%时, 复合油墨具有最优的流变学性能; 在丝网印刷中, 该油墨在聚酰亚胺基底上形成均匀致密的涂层. 在微观上, 涂层具有夹层三维网络结构, 电阻率为0.23±0.01 Ω cm (92±4 Ω sq⁻¹, 25 μm), 是纯炭黑涂层电阻率(0.77±0.01 Ω cm)的30%. 辊压处理后, 电阻率降至0.18±0.01 Ω cm (72±4 Ω sq⁻¹, 25 μm), 且涂层具有良好的机械柔性, 经过3000次循环弯折试验后电阻仅增加12%. 最后, 我们将石墨烯/炭黑复合涂层作为柔性导体, 成功组装了发光书签和薄膜开关, 表明该涂层在柔性电子器件大规模生产中具有巨大的潜力.