Facile fabrication of a fast-response flexible temperature sensor via laser reduced graphene oxide for contactless human-machine interface

Temperature sensors are indispensable in healthcare, human-machine interface, robotics, and other areas. However, facile and rapid fabrication of flexible temperature sensors with good performance are still required. In this work, a fast-response flexible temperature sensors is fabricated in a facile manner on the basis of laser-reduced graphene oxide(GO) for contactless human-machine interface. The combined effects of the GO concentration and scan line spacing of the laser on the sensitivity of the temperature sensor are investigated systematically. The intrinsic correlation among the two critical process parameters, material properties, and sensor sensitivity is revealed. Results show that the temperature sensor achieves the highest sensitivity of 0.37% °C−1 when the GO concentration is 4 mg/mL and the scan line spacing is 0.12 mm. The temperature sensors fabricated using the optimized process parameter also have a fast response time, good linearity, small hysteresis, good repeatability, and stable performance, and are successfully used to monitor human breathing, blowing, and spatiotemporal temperature variation of a curved surface. The sensors can also detect finger proximity. In addition, a 3 × 3 flexible temperature sensor array is fabricated for contactless unlocking of a code lock. The fabricated array reveals the great potential of the sensors developed in this study for contactless human-machine interface.