Flexible Resistive Pressure Sensors with High Sensitivity and Wide Detection Range

In this paper, flexible resistive pressure sensors with high sensitivity and wide detection range are presented. The sensor is designed to be a sandwich structure consisting of three parts: a flexible pressure-sensitive layer and two ohmic contact electrodes. The flexible pressure-sensitive layer is essentially a variable resistor, which is made of Polydimethylsiloxane (PDMS) doping nano iron particles ( $n$ mFe). The high performance of these sensors is realized by controlling the distribution of the conductive nano iron particles within the flexible substrate PDMS and two magnetics are used during the PDMS curing. The doped nano iron particles lined up in PDMS along the direction of magnetic field and the resistance of the flexible pressure sensitive layer mainly depends on the contact state of the nano iron particles. As a result, the resistance of the pressure sensor decreases when the pressure is applied. Both the magnetic field and the weight ratio of $n$ mFe have an effect on the device performance. One of the fabricated sensors displays a sensitivity of 3.5kPa ⁻¹ and a detection range of 0-1000kPa.