A dual function flexible sensor for independent temperature and pressure sensing

Temperature and pressure sensing are two primary goals of bionic electronic skin. In this work, we developed a dual function flexible sensor, which achieved independent temperature and pressure sensing, with easy fabrication and without complicate signal decoupling. For this sensor, two flexible films with conductively bionic microstructure on the surface are combined face to face, which were replicated from rose petal and mulberry leaf. Ti3C2Tx nanoflakes were mixed with PEDOT: PSS as conductive layer and thermoelectric layer, and the performance of which can be optimized by regulating the concentration of Ti3C2Tx. The principles for temperature and pressure sensing are thermoelectric and piezo-resistive respectively, which are isolated by structure design. The change of contact area and resistance between the two micro-structured layers upon pressure determines the pressure response of the device. The thermoelectric response in one layer realizes the temperature sensing. The metallic conductivity of Ti3C2Tx is insensitive to temperature, leading to the invariable electric response to pressure upon varied temperature. The microstructure buffers most of the pressure, which keeps the substrate unchanged and results in the independent thermoelectric response upon varied pressure. This dual function sensor shows robust and repeatable response, and exhibits great application potential in flexible electronics