This Small Business Innovation Research (SBIR) Phase II project aims to develop high-performance graphene-based conductive inks for printed electronics to meet its stringent cost, flexibility, and conductivity requirements. Components printed with existing conductive inks are challenged by repeated flexing cycles that can break conductive paths. In this project, a graphene filler technology and a novel formulation will be used to achieve the combination of electrical, mechanical, and environmental durability properties specified for the flexible printed electronics at a price point that enables high-volume applications.
The broader/commercial impact of this project will be the availability of a conductive ink that meets performance requirements of next-generation printed electronics. The printed electronics market is growing across multiple sectors driven by applications including radio-frequency identification (RFID) tags for tracking inventory, smart packaging for anti-theft and anti-tampering purposes, smart cards and printed displays. Conductive inks are a critical component in printed electronics, and limitations of existing conductive inks have curtailed market growth. The new graphene-based conductive inks are expected to demonstrate flexibility and mechanical robustness that improves lifetime and performance of printed electronics, while providing significant cost advantage over silver-based inks currently widely used in printed electronics industry.
The $3 billion conductive ink market – and the plethora of innovations possible through printed electronics – has been significantly limited by the attributes of traditional inks. Conductive inks containing silver are too expensive or too fragile to be used in many printed electronic applications, while conventional carbon inks are often too resistive. However, graphene, a sheet of carbon a single atom thick has enabled the development of low-cost, highly conductive, and mechanically robust inks by Vorbeck Materials, www.vorbeck.com, in this SBIR program. During Phase I, Vorbeck simultaneously increased the conductivity of its base ink formulation by 30% and improved mechanical flexibility and durability. In Phase II, researchers were able to expand upon their successes in Phase I and create a synergistic system between the graphene, solvents, binders, and select additives. Additionally, the team was able to develop inks for a range of substrates and applications. Thirteen new commercial ink formulations were released through this phase of the program covering both screen and flexographic printing processes. These inks are up to 2.5 orders of magnitude more conductive than conventional carbon inks, with formulations granting 1 ?/sq/mil available on the company’s online store. Inks are available for plastic, paper, glass, fabric, and leather substrates granting product designers an increasingly flexible toolset for the next generation of electronics. These inks, which form the Vor-ink™ product line, have been used in aerospace, automotive, consumer electronic, RFID, smart packaging, and wearable electronic applications, including use in products that are on retail shelves today. During the Phase II program, Vorbeck developed REACH compliant formulations to facilitate export to European customers. Currently, Vorbeck is enhancing its printing capabilities, and developing intermediate and end-use products using its inks such as printed articles ranging from circuit traces and heaters, to antennae and full coatings. At the same time the company is seeking to continuously improve the conductivity of its inks in order to open up more and more opportunities for low cost, ubiquitous printed electronics. Creating electronics in this way represent a key step in moving towards efficient and environmentally friendly additive manufacturing, a process which can be rapidly and cost-effectively customized for specific projects, and which is seen as a major competitive advantage to enabling increased prevalence of domestic manufacturing.
