Organic transistor-based mechanical sensors for artificial skin applications
The human skin is endowed with a big amount of tactile receptors, which perceive mechanical and thermal stimuli and allow the arising of different feelings (smoothness/roughness, softness/hardness, hotness/coldness, pain, etc.), also detecting stimulus position, size and duration. The biggest challenges that come from the development of tactile systems concern not only the need of fabricating multimodal tactile transducers, but also the fact that these sensing capabilities must be distributed on large, complex areas and possibly at low fabrication costs, dealing with still open issues such as the reduction of the numbers of connecting cables, the realization of a dedicated network architecture, the reduction of power dissipation and last but not the least the reduction of fabrication costs. From this point of view, Organic Electronics represents a step forward as conjugated polymers join the mechanical characteristics of plastics, therefore highly flexible and easily transferrable on whatever kind of surface, with the possibility of being solution processable. This property is particularly important, because it allows processing and deposition of these materials on large areas with very easy and cost-efficient technologies suitable for mass production, such as inkjet printing. The focus of this chapter is in particular on the employment of electronic devices based on conjugated materials for the realization of strain/pressure sensors that may be used for the fabrication of artificial skin.