Small capacitive graphene-based sensors

Purpose and goal

The main purpose of this feasibility study was to investigate the possibility to develop graphene-based capacitive sensors for providing the market with smaller (>50%) and flexible displacement and gap sensors, capable of working at high temperature (>260C) and no heating in high electric and magnetic field applications. As a reference sensor for this feasibility study a similar silver-based test-sensor was prepared. The subsequent measurements resembling industrial methods were prepared and successfully executed.

Expected results and effects

We have successfully prepared and measured graphene-based flexible high temperature air gap test-sensors capable to handle high electric and magnetic fields, and it performs equally good as our silver-based reference test-sensor. Our graphene-based test-sensor presented nearly linear behavior for air gaps in the range of hundreds of micrometers. Eddy-current measurements did not show any impact on the test-sensor from high electrical and magnetic fields. We cannot argue a 50% footprint decrease as there are a vast number of capacitive sensors of different size and performance.

Planned approach and implementation

Aninkco and KTH prepared the graphene ink and the graphene capacitive sensors by inkjet printing. Aninkco and KTH fabricated the test-sensors and performed preliminary measurements, and MacDonald-Arnskov have performed the measurements resembling industrial methods. We have shown that our graphene-based sensors has a good potential to be used as an active material in capacitive sensors. By carefully designing the measurement system and a more elaborate sensor layout using shields would imply an even greater potential for our graphene-based sensors.