Fully Printed Sensors for In Situ Temperature, Heat Flow, and Thermal Conductivity Measurements in Flexible Devices

Flexible temperature sensors allow temperature monitoring in wearable healthcare devices. A temperature sensor, which can be printed on flexible substrates, is designed and fabricated using a low-cost silver particle ink and a fast and scalable screen-printing process. A high temperature resolution of 10 m°C is reached. The versatility of this temperature sensor design is demonstrated for various applications, including in situ heat flux measurements, where a 2 mW cm^-2 resolution is reached, and thermal conductivity measurements on polymer films as thin as 25 μm, with a wide range of accessible values from ∼0.1 to 0.8 W K^-1 m^-1.