The excessive production of material waste by humankind means a serious threat to the environment, and the problem is only increasing. Disposable electronic devices, like smartphones, are a rapidly growing source of waste. One way to reduce the problem could be to use components made from renewable resources and easy to eliminate responsibly.
The majority of the smallest electronic devices have a circuit board that is manufactured with fibreglass, resins and metallic cables. These boards are not easy to recycle and are relatively bulky, which makes them not suitable for use in medical equipment , environmental monitors or portable personal devices.
An alternative is to use paper circuit boards, which should be easier to remove, less expensive and more flexible. However, current options require specialised paper or conventional metal circuit components fitted on a sheet of paper.
Instead, the developers of this new research wanted to develop circuits that were simple to manufacture and had all the electronic components fully integrated into the sheet. They want to create an environmentally friendly and cost-effective, all-paper device for single-use applications that can be easily and safely disposed of by incineration or biodegradation.
The team designed a paper amplifier-type circuit incorporating resistors, condensers and the transistor. Firstly, they use wax to print the channels on the sheet of paper following a simple pattern. After melting the wax to impregnate the paper, the team printed semiconducting and conductive dyes, which were impregnated in the areas not blocked by the wax. Then the researchers screen-printed additional conductive metal components and fused a gel-based electrolyte onto the sheet.
Tests confirmed that the resistors, condensers and transistor were working properly. The final circuit was very flexible and thin as paper, even after adding the components. To measure the degradability of the circuit, the team demonstrated that the entire unit would quickly turn to ash when set on fire. Researchers say this represents a step towards the production of entirely disposable electronic devices.
The technical details of their new technology can be found in the academic journal ACS Applied Materials & Interfaces, under the title "Integrated Papertronic Techniques: Highly Customizable Resistor, Supercapacitor, and Transistor Circuitry on a Single Sheet of Paper".
Profesional, R. and Profesional, R., 2022. Electrónica desechable en una hoja de papel. [online] Residuos Profesional. Available at: <https://www.residuosprofesional.com/electronica-desechable-hoja-papel/> Landers, Mya; Elhadad, Anwar; Rezaie, Maryam; Choi, Seokheun (1753): Integrated Papertronic Techniques: Highly Customizable Resistor, Supercapacitor, and Transistor Circuitry on a Single Sheet of Paper. ACS Publications. Collection. https://doi.org/10.1021/acsami.2c13503
Landers, Mya; Elhadad, Anwar; Rezaie, Maryam; Choi, Seokheun (1753): Integrated Papertronic Techniques: Highly Customizable Resistor, Supercapacitor, and Transistor Circuitry on a Single Sheet of Paper. ACS Publications. Collection. https://doi.org/10.1021/acsami.2c13503