Fully inkjet-printed dual-mode sensor for simultaneous pressure and temperature sensing with high decoupling

Pressure-temperature dual-mode sensors have been attracting much attention for their various potential applications in areas such as human–computer interaction and health monitoring. However, it is still a challenge to construct an all-in-one dual-mode sensor on a flexible substrate through a simple process. Herein, a flexible dual-mode sensor based on the pressure-capacitance sensitivity of porous polydimethylsiloxane (PDMS) and the temperature-resistance sensitivity of reduced graphene oxide (rGO) film has been fabricated. The dual-mode sensor not only owns an excellent pressure sensing capabilities with ultra-wide detection range (0–1000 kPa), a low-pressure detection limit (2.5 Pa), a fast response time (40 ms) and a high cyclic stability (10,000 cycles), but also can accurately distinguish a temperature change of 0.2 °C. In addition, theoretical formulas are successfully developed to explain the causes of signal crosstalk. Effective decoupling is achieved according to the mechanistic analysis, and the detected capacitance and resistance signals are converted into the actual pressure and temperature. Furthermore, a dual-mode sensor array is fabricated by fully inkjet printing method that incorporate the structure of the dual-mode sensor unit and the circuit design of shared electrodes to reduce the complexity of circuit layout for multi-position detection. Besides, a pressure-temperature alarm system is constructed using this dual-mode sensor to monitor different environmental changes. Based on its superior sensing performance and decoupling capabilities, the sensor has great potential in multifunctional synchronous sensing scenarios.