Conductive Inks

Conductive ink is an ink that results in a printed object which conducts electricity. The transformation from liquid ink to solid printing may involve drying, curing or melting processes.

These inks may be classed as fired high solids systems or PTF polymer thick film systems that allow circuits to be drawn or printed on a variety of substrate materials such as polyester to paper. These types of inks usually contain conductive materials such as powdered or flaked silver and carbon like materials, although polymeric conduction is also known.

Conductive inks can be a more economical way to lay down a modern conductive traces when compared to traditional industrial standards such as etching copper from copper plated substrates to form the same conductive traces on relevant substrates, as printing is a purely additive process producing little to no waste streams which then have to be recovered or treated.

Silver inks have multiple uses today including printing RFID tags as used in modern transit tickets, they can be used to improvise or repair circuits on printed circuit boards. Computer keyboards contain membranes with printed circuits that sense when a key is pressed. Windshield defrosters consisting of resistive traces applied to the glass are also printed. Many newer cars have conductive traces printed on a rear window, serving as the radio antenna.

Printed paper and plastic sheets have problematic characteristics, primarily high resistance and lack of rigidity. The resistances are too high for the majority of circuit board work, and the non-rigid nature of the materials permits undesirable forces to be exerted on component connections, causing reliability problems. Consequently such materials are only used in a restricted range of applications, usually where the flexibility is important and no parts are mounted on the sheet.

  • 3D printer inks from the woods

    Rod-like cellulose nanocrystals (CNC) approximately 120 nanometers long and 6.5 nanometers in diameter under the microscope. (Image: Empa)

    Empa researchers have succeeded in developing an environmentally friendly ink for 3D printing based on cellulose nanocrystals. This technology can be used to fabricate microstructures with outstanding mechanical properties, which have promising potential uses in implants and other biomedical applications.

    In order to produce 3D microstructured materials for automobile components, for instance, Empa researchers have been using a 3D printing method called “Direct Ink Writing” for the past year (DIW, see box). During this process, a viscous substance – the printing ink – is squeezed out of the printing nozzles and deposited onto a surface, pretty much like a pasta machine.

  • Hannover Messe: Inkjet process to print flexible touchscreens cost-efficiently

    Printed, flexible touchscreen. Source: INM

    INM - Leibniz Institute for New Materials will be demonstrating flexible touch screens, which are produced by printing recently developed nanoparticle inks on thin plastic foils. These inks composed predominantly of transparent, conductive oxides (TCOs) are suitable for a one-step printing process. Flexible smart phones are desirable for a lot of users. Up to now the displays of the innumerable phones and pods are rigid and do not yield to the anatomical forms adopted by the people carrying them. By now it is no longer any secret that the big players in the industry are working on flexible displays. INM – Leibniz Institute for New Materials shows, how they might become reality in the near future: At this year’s Hannover Messe, INM will be presenting suitable coatings for cost-efficient inkjet processes at the stand B46 in hall 2 from on 24 April to 28 April.

  • Hannover Messe: New hybrid inks for printed, flexible electronics without sintering

    New type of hybrid inks  allow electronic circuits to be applied to paper directly from a pen. Source: INM

    Research scientists at INM – Leibniz Institute for New Materials have now developed a new type of hybrid inks which allows electronic circuits to be applied to paper directly from a pen, for example. Flexible circuits can be produced inexpensively on foil or paper using printing processes and permit futuristic designs with curved diodes or input elements. This requires printable electronic materials that retain a high level of conductivity during usage in spite of their curved surfaces. Research scientists at INM – Leibniz Institute for New Materials have now developed a new type of hybrid inks which allows electronic circuits to be applied to paper directly from a pen, for example. They are usable after drying without any further processing.

  • Hannover Messe: Successful Small-scale Production of New Hybrid Inks

    Flexible electronics with hybrid inks. Source: INM; free within this press release

    Research scientists at INM – Leibniz Institute for New Materials have developed a sinter-free conductive ink based on gold and silver nanoparticles coated with conductive polymers. INM’s hybrid inks enable inkjet printing of conductive structures without any thermal or UV treatments. The inks can be prepared in polar solvents such as water and alcohols, and many of their properties such as their density or viscosity can be customized. Testing samples will be available upon request.

  • Industrial Maturity of Electrically Conductive Adhesives for Silicon Solar Cells Demonstrated

    Solar cells with three, four or five busbars can be interconnected in the adhesive stringer. © Fraunhofer ISE

    The Fraunhofer Institute for Solar Energy Systems ISE and teamtechnik, an international leader in production technology, report that it is now possible to connect high efficiency solar cells using electrically conductive adhesives in series production. The results of the joint research project »KleVer« show that the adhesive technology is ready for the market and can be used as an alternative to the widespread soft soldering interconnection technology. Due to the much lower process temperatures of this technology compared to soldering, temperature-sensitive high efficiency solar cells can be connected using adhesives in a gentle and material-saving process.

  • Micro Energy Harvesters for the Internet of Things

    The engineers coated a glass plate with a particularly smooth and conductive polymer layer of “Poly(Kx[Ni-itto])” by rotation coating (“spin coating”). Fraunhofer IWS Dresden

    Thin organic layers provide machines and equipment with new functions. They enable, for example, tiny energy recuperators. In future, these will be installed on pipes or other surfaces in order to convert waste heat into electricity. The experts at the Fraunhofer Institute for Material and Beam Technology IWS Dresden use ink based on conductive polymers for this purpose.