Graphene based touch sensors developed in this work will make artificial limbs to fill the environment like humans.
In March 2017, we have published a journal article in Advanced Functional Materials, about the integration of transparent and flexible graphene touch sensors and photovoltaic cells realizing an energy-autonomous electronic-skin for robots.
In this work, we present a high-performance technique based on hot-lamination to transfer single layer graphene from the growth substrate to transparent and flexible substrates, preserving graphene properties, i.e. structural, morphological, and electrical properties.
Single layer graphene is transferred to plastic substrates using hot-lamination technique.
Once graphene is transferred to a plastic substrate, it is patterned using techniques such as blade-cutting and laser-cutting to fabricate interdigitated electrodes. Resulting co-planar capacitive structures based on single layer graphene have demonstrated to be sensitive not only to touch but also to pressure, which make these sensors to be excellent candidates to electronic-skin.
Graphene absorbs around 2% of light, which allows us to place a photovoltaic cell underneath the touch sensors to harvest sunlight energy and to power the sensors.
The high transparency of graphene and the plastic substrate, allowing the light to pass through the whole structure without losing intensity, is a key feature of the touch sensor that has been used to integrate a photovoltaic cell underneath to harvest sunlight energy. Energy harvested by the photovoltaic cells is used to power the touch sensors, giving them autonomy to work without any external battery. In future, the integration of better solar cells and energy-storing technologies will allow to fabricate a fully energy-autonomous electronic-skin able to work 24h a day without any external battery.