Graphene printing gets speed boost

The method permits high-speed and low-cost printing of electronics and disposable sensors, allowing electric ink printing to be conducted on a commercial scale for the first time.

The technique involves suspending graphene particles in a ’carrier’ solvent mixture, which is then added to conductive water-based ink formulations. The ratio of the mixture can be later adjusted to control electrical resistance.

This enables electric-conducting materials to be added to conventional water-based inks, and printed on large-scale roller equipment.

The same method also works for materials other than graphene, such as metallic, semiconducting and insulating nanoparticles, the researchers suggested.

Printed conductive patterns currently combine poorly conducting carbon with other materials, most commonly silver, which is expensive and cannot be recycled.

However, graphene is recyclable and uses quick-drying non-toxic solvents that reduce the costs of curing, the researchers said.

Until now, efforts to commercialise the use of graphene have been limited, despite its flexibility and electrical conductivity.

“There are lots of companies that have produced graphene inks, but none of them have done it on a scale close to this,” said Cambridge researcher Tawfique Hasan.

Researchers said the technique has been tested on commercial equipment without modification, printing at a rate of 100m per minute, in line with commercial production speeds.

“Being able to produce conductive inks that could effortlessly be used for printing at a commercial scale at a very high speed will open up all kinds of different applications for graphene and other similar materials,” said Hasan.

The researchers worked with Cambridge-based technology firm Novalia to produce the new method.

The researchers now hope to use their method to make printed and disposable biosensors, energy harvesters and radio-frequency identification (RFID) tags.