Flexible temperature sensors based on optimized paper/Cu/Al2O3 and graphene/PVDF composite sensing layers

Wearable devices have great potential for development in the fields of human health detection and human-computer interaction due to its flexibility and portability. In this work, Firstly, the resistance response performance of paper/Cu/Al 2 O 3 to temperature is optimized by changing the sputtering time of Al 2 O 3 . Combining the resistance change and stability after one month, paper/Cu/Al 2 O 3 films with 1 min Al 2 O 3 layer is selected. Then, temperature sensor based on optimized paper/Cu/Al 2 O 3 and graphene/PVDF composite temperature-sensitive layers is fabricated. The sensor shows negative temperature coefficient, high temperature response and stability, which provides significant advantages in the field of temperature monitoring. The fastest response/recovery time of the sensor is 1.4 s and 10.48 s respectively, which is fast and reliable in capturing the temperature changes and thus has the capability of real-time temperature monitoring. Another outstanding feature of the sensor is its high linearity to temperature fluctuations (R 2 =0.947). This feature suggests that the sensor enables real-time resistance-temperature interaction. In addition, its practical applications will be explored. The sensor can quickly sense the temperature of fingers, hot water, and working mobile phones. At the same time, the excellent performance of the sensor enables it to achieve the function of illuminating the LED. It lays the foundation for the application of temperature sensors in flexible wearable device applications.