Materials for Printed Electronics: Copper Inks

Copper based inks have been gaining interest as a potentially cheaper alternative for the conventional, market ready conductive silver inks. However, most of the current copper inks in the market have the tendency to oxidize under room conditions, leading to performance issues and thereby limiting their adoption. This technology presents a range of conductive materials, specifically copper inks, targeted at the flexible printed hybrid electronics sector. These functional materials are specifically designed to be printable, cured at low temperature and flexible, making them ideal for printed electronics. Furthermore, the inks have been formulated to be extremely stable under ambient conditions, providing several advantages over the existing state of the art.

Two variations of copper inks are available: copper complex ink, and copper particle ink. Current methods for for electroless plating applications are achieved using palladium seed which is very costly. Copper complex ink can form a good base for such applications where building of circuit or electrodes on 3D images are an issue, providing a good, cost-effective alternative solution for the manufacture of printed electronics.

The described technology composes of the following features:

• Stable copper ink formulations which ensure that oxidation is kept to the minimum, these enhances shelf life, and printed circuitry performance and reliability Formulated inks that can be ink-jetted, screen printed, and used in roll-to-roll processes. 
• Inks that can be formulated to be sintered at low temperatures and/or through various methods

This technology is applicable (but not limited) to printed electronics in general. The inks enable the printing of conductive traces on both flexible and rigid substrates. Examples of these are:

• Printed photovoltaic
• Printed lighting Touchscreen
• Printed heaters
• Printed displays
• Printed antenna
• RFID tags
• EMI shielding
• Alternative replacement of silver inks

• The functional materials enable printable flexible electronics
• Unique copper complex ink (no such ink currently commercially available)
• Long shelf life without risk of oxidation (copper complex ink)
• Major cost savings can be achieved
• Suitable for multiple decomposition/sintering methods such as laser, plasma and low temperature heating
• The technology/capability to work with customers in tweaking ink formulation based on their requirements