Inkjet printed Organic Thin Film Transistors based tactile transducers for artificial robotic skin

We present a novel and flexible system to be employed for tactile transduction in the realization of artificial "robot skin". The mechanical deformation detection, which functionally reproduces the sense of touch, is based on Organic Thin Film Transistors (OTFTs) assembled on a flexible plastic foil, where each device acts as a strain sensor. OTFT-based mechanical sensors were fabricated employing a solution-processable organic semiconductor, namely 6,13-bis(triisopropylsilylethynyl)-pentacene (TIPS-pentacene) deposited by drop casting. It will be shown that the surface deformation induced by an external mechanical stimulus gives rise in both cases to a marked, reproducible, and reversible (within a certain range of surface deformation) variation of the device output current. Starting from these results, more complex structures, such as arrays and matrices of OTFT-based mechanical sensors, have been fabricated by means of inkjet printing. Thanks to the flexibility of the introduced structure, we will show that the presented system can be transferred on different surfaces (hard and soft) and employed for a wide range of applications. In particular, it can be successfully employed for tactile transduction in the realization of artificial "robot skin".