Printed wearable temperature sensor for health monitoring

We developed a printed high sensitive temperature sensor by synthesizing poly (3, 4-ethlenedioxythiophene) poly (styrenesulfonate) (PEDOT:PSS) and carbon nanotubes (CNTs) composition ink on a flexible substrate. There are two advantages of this flexible temperature sensor, which are (1) high sensitivity (~0.6%/°C) compared to other reported flexible temperature sensors, (2) fully-printable low-cost process on macroscale flexible substrates due to solution-based process. The key point to achieve the high sensitivity was a mixture of PEDOT:PSS and CNTs for the temperature sensor material. Based on the analyses, the mechanism of this high sensitivity is most likely due to electron hopping at the interface of PEDOT:PSS and CNTs. In addition to the sensor analyses, real-time human skin temperature was monitored by attaching on a human skin like a bandage as a proof-of-concept, and it was successfully conducted to observe small skin temperature change during activities.