Aerosol Jet Printing of Multi-Dimensional OECT Force Sensor with High Sensitivity and Large Measuring Range

Abstract

Multi-dimensional tactile force sensors with high sensitivity, large measuring range, and direction recognition are essential for human-machine interaction, medical rehabilitation, and humanoid robotics. Current tactile force sensors mainly make use of bump structure or 3D patterned composite layers to achieve multi-dimensional force sensing, which not only results in thick sensors with unadjustable measuring performance, but brings about significant difficulties in fabrication. Here, an organic electrochemical transistor (OECT) based thin multi-dimensional force sensor with tunable range/sensitivity has been designed with unilateral conductive micro-riblets array, and aerosol jet printing was developed to build the unilateral conductive structure and multi-material layers. Such unilateral conductive micro-riblets array's directional dependent deformation endows the sensor with the capacities of lateral force response and force direction recognition. With the profound contact area sensitivity from super capacitance effect and signal amplifying of OECT, the aerosol jet printing OECT force sensor shows an adjustable sensing performance with high sensitivity of ≈1.45 kPa−1 at low-pressure range of 0–500 Pa and a large measuring range even up to as high as 50 kPa. Finally, several tactile sensing applications have been demonstrated for the sensor's multifunctional performance.