A new process for creating flexible large area electronics could lead to breakthroughs in technologies including prosthetics, high-end electronics and fully bendable digital displays. printers in cardiff
This is the claim of a team of engineers from Glasgow University’s Bendable Electronics and Sensing Technologies (BEST) group who have developed a new method for manufacturing electronics that prints high-performance silicon directly onto flexible materials. The EPSRC-supported research is described in a paper published in NPJ Flexible Electronics.

Until now, the most advanced flexible electronics have been mainly manufactured via a three-stage stamping process called transfer printing. printers in cardiff

In the process, a silicon-based semiconductor nanostructure is first designed and grown on a substrate. In the second stage, the nanostructure is picked up from the substrate by a soft polymeric stamp. In the final stage, the nanostructure is transferred from the stamp to another flexible substrate, ready for use in bendable devices like health monitors, soft robotics, and bendable displays. printers in cardiff

According to BEST, the transfer printing process has a number of limitations which have made it challenging to create more large-scale, complex flexible devices. Precisely controlling critical variables such as the speed of transfer, and the adhesion and orientation of the nanostructure, makes it difficult to ensure each stamp is identical to the last. An incomplete or misaligned polymeric stamp onto the final substrate can lead to substandard electronic performance or even prevent devices from working.

Processes have been developed to make the stamping transfer more effective, but they often require additional equipment like lasers and magnets, which adds extra manufacturing cost.

The Glasgow team said they have eliminated the second stage of the conventional transfer printing process and replaced it with ‘direct roll transfer’ to print silicon straight onto a flexible surface.

The process begins with the fabrication of a silicon nanostructure of less than 100nm. The receiving polyimide substrate is then covered in an ultrathin layer of chemicals to improve adhesion.
The prepared substrate is wrapped around a metal tube, and a computer-controlled machine developed by the team then rolls the tube over the silicon wafer, transferring it to the flexible material.

By optimising the process, the team created highly-uniform prints over an area of about 10cm2, with around 95 per cent transfer yield, which they said is significantly higher than most conventional transfer printing processes at the nanometre scale.