High-linearity graphene-based temperature sensor fabricated by laser writing

In this work, the preparation of high-linearity flexible graphene-based temperature sensors by laser writing directly on polyimide (PI) substrates was proposed. The combined effects of the power density of the laser and the scan path line width on the linearity and sensitivity of the temperature sensors are systematically investigated. Results show that the linearity of the temperature sensor is demonstrated to reach 0.999 in the range of 30 °C to 100 °C when the laser power density of 76 J/cm² with a path width of 0.8 mm is used. The sensitivity of the LIG sensor is 0.05%°C⁻¹. The findings also suggest that the temperature sensor exhibits the characteristics of quick response (2 s), short recovery time (3.9 s), good repeatability, reliability, stability and flexibility. Moreover, the obtained temperature sensors were successfully applied to human respiration monitoring and water level measurement. Our results indicated that the proposed temperature sensors are promising for the application of temperature sensing.