Lowering the cost of manufacturing electronic components is a priority for many industries. It appears that flexible and plentiful paper could well provide an economic solution.
Is paper set to become a key new material for manufacturing electronic chips? Work carried out by Stefan Glatzel and a team of researchers at the Max Planck Institute of Colloids and Interfaces in Potsdam, Germany, has shown how paper can be transformed into an electrically conductive material. This solution seems likely to solve a deficiency in the current process of electronic component production. At the moment, plastics are the material mainly used as the carrier in flexible chips, but these substances do not tolerate the very high temperatures required to build an electronic circuit, which means that processing cannot be integrated into normal electronics manufacture but must be performed separately. The solution that the German scientists have come up with transforms paper into an electronic component by using heat.
The method is relatively simple. First, an inkjet printer prints a catalyst in a certain pattern on a sheet of paper. The Max Planck Institute explains that if the researchers then heat the sheet that was printed with a catalyst to 800° Celsius in a nitrogen atmosphere, the cellulose will continue to release water until all that remains is pure carbon. So “an electrically conducting mixture of regularly structured carbon sheets of pure-carbon graphite and iron carbide forms in the printed areas, while the non-printed areas are left behind as carbon without a regular structure, and they are less conductive.” The Max Planck researchers took their Minerva symbol as the printed pattern, which – now composed of conductive graphite – was then used as the cathode in a process of electrolysis to produce a copper-coated Minerva. This demonstrated that a simple pattern on a piece of paper had been successfully converted into electricity-conducting material.
3D components too
In another experiment, the team in Potsdam demonstrated how three-dimensional, conductive structures can be created using the same method, this time by dipping the 3D object into the catalyst. There are many potential applications for this research, including RFID chips, ‘connected’ clothing that can monitor vital signs, and flexible screens. This discovery could also make for huge savings in the electronic components industry, as it uses a readily available, relatively cheap, resource.