Conductive Inks for Electronic Printing
Printed electronics covers a range of processes whereby relatively old manufacturing techniques are combined with novel materials to produce cutting-edge devices. The best example of this is the thin film; an electronic stack comprised of multiple layers of conductive materials deposited via inkjet printing, spin coating, or some other standard application technique. In the context of thin film deposition, the novel material is the electronic ink.
Electronic inks for printing provide a range of capabilities which significantly impact end-product performance as well as the cost of production. Conductive inks, for example, enable manufacturers to produce coatings and intricate patterns with fine-tuned electrical properties. They are an extremely valuable alternative to copper when producing conductive traces in printed circuit boards (PCBs), and are increasingly used to generate high-performance thin film stacks for organic light emitting devices (OLEDs).
What is Conductive Ink Used for?
Currently, electronic inks for printing are primarily used to manufacture solution-processed OLED devices and organic photovoltaics (OPVs), but the industry is constantly growing. The global market for printed electronics is estimated in the region of $45 billion as of 2021, with conductive inks and printable dielectrics emerging in an array of non-traditional applications. Electronic textiles and lightweight, flexible wearable devices have been under development for some time, with researchers continually pushing the technological letter beyond the initial remit of conventional silicon-based electronics applications.
Overcoming Manufacturing Challenges
Despite the considerable growth of electronic inks for printing, key manufacturing challenges must be overcome before the full economic potential of conductive inks can be realised. Firstly, production methods and materials must continually meet greater complexity requirements while facilitating the integration of different components. In the case of OLED panels, multiple different inks are deposited sequentially; so, compatibility is an important consideration.
Secondly, ink deposition speeds and curing times directly affect manufacturing throughput. Monitoring uniformity and carefully controlling drying temperatures is vital to optimising product yields and ultimately creating a profitable and scalable production line. Similar attention must be paid to substrate properties. Although modern electronics printing has largely resolved many material challenges with respect to optimal substrate properties (smoothness, porosity, ink uptake, etc.) and ink properties (stability, rheological behaviour, etc.), novel conductive inks and non-conventional substrates will require extensive study to determine chemical and physical compatibility, printability, and more.
Types of Conductive Ink from Avantama
Common conductive inks are based on carbon, typically graphite, or silver. They are formatted usually as nanoparticles or flakes dispersed in solutions. These typically offer good resistivity and fine-line resolutions at a reasonable price point. However, proprietary applications typically require specific chemistries and finely tuned electronic/physical properties that commodity inks cannot guarantee.
At Avantama, we offer an off-the-shelf portfolio of almost thirty different inks for printed electronics with compositions based on nickel oxide (NiO); tin dioxide (SnO2); tungsten trioxide (WO3); and zinc oxide (ZnO), including aluminum-doped zinc oxide (Al:ZnO). Each of our standard solutions is formatted to tight mean particle sizes and is dispersed in a choice of solvents. This ensures that we can quickly supply an appropriate solution for almost any electronics printing methodology