An Effective Methodology for Achieving Highly Reliable Physical Sensors with High Sensitivity and Low Hysteresis through Parallel-Structured Piezoresistors

Abstract

The representatively chronic problems of the piezoresistive-type sensing media containing conductive fillers such as carbon nanotubes are dispersion problem when conductive fillers are composited with a high content for securing a certain conductivity and are low reliable sensor performance owing to the hysteresis of the sensing signals. Therefore, this study introduces a piezoresistive sensing medium with a multilayered parallel structure of resistors which effectively reduces the resistance and stabilizes the sensing signal. The multiparallel resistor (MPR) sensing medium with parallel-connected structure shows an initial resistance approximate to 2.5 times lower compared to that of the typical single-resistive type. When the proposed MPR sensing medium is applied as a strain sensor, GF value is 0.103 +/- 0.009%(-1) showing a remarkable improvement over 0.030 +/- 0.018%(-1) of the single type. The MPR strain sensor exhibits approximately the same GF values with no hysteresis and high linearity of the sensing signals in the forward and reverse strain directions. Finally, the developed MPR sensing medium is applied both as a strain sensor as well as a pressure sensor with excellent performance, thereby suggesting a new methodology to develop the high-performance piezoresistive physical sensors.