A flexible resistive temperature detector (RTD) based on in-situ growth of patterned Ag film on polyimide without lithography

Flexible resistive temperature detectors (RTDs) based on metal thin film have broad application prospects in the field of portable and wearable electronics. However, most of flexible RTDs are constructed with patterned metal films using complicated manufacturing processes due to the lack of simple, scalable, environmentally friendly processing technologies. In this work, we report a flexible RTD based on in-situ growth of patterned Ag film on polyimide without lithography. The manufacturing process of flexible RTD is realized by combining ion-exchange surface modification with laser inkjet printed carbon masking processes. The developed RTDs exhibit high sensitivity and good linearity. The sensitivity in the range of -20 to +100 degrees C is 0.36% per degrees C and the linearity is similar to 0.16%. In addition, the flexibility and the mechanical stability of the RTDs are outstanding, with negligible degradation even in severe bending states and after 5000 times bending cycling. For demonstration, the devices are utilized to monitor the human body temperature. Therefore, this RTD demonstrates potential applications in detecting environmental temperatures, thereby marking an important progress for constructing advanced electronic skin for flexible robots. This flexible RTD opens up a new opportunity for the development of wearable and portable temperature detection devices.