Aerosol Jet Printing and Photonic Flash Sintering of a Flexible Multimodal Sensor for Concurrent Temperature and Strain Sensing

Multimodal sensors have numerous integrated sensing capabilities that enable a wide range of applications, including but not limited to structural, environmental, biohealth monitoring, soft robotics, etc. Complex manufacturing processes of multimodal sensors limit the choice of sensing materials and device form factors. Herein, we present aerosol jet printing combined with ultrafast photonic sintering (<2 s) to fabricate high-performance flexible multimodal sensors for simultaneous strain and temperature sensing using gold and indium tin oxide (ITO) nanoparticle inks. Strain measurement accuracy can be significantly enhanced via integrated thermocouples as the in situ temperature sensing can decouple the resistance change of the strain gauge due to temperature and strain. The sensor can detect the strain by measuring the resistive voltage change of the gauge, while the Seebeck voltage generated at the thermocouple junction can detect the temperature. The printed multimodal sensor shows a temperature measurement sensitivity of 51.6 μV/°C and a gauge factor of 2.5 with excellent repeatability. The flexible sensor shows negligible performance degradation after 500 bending and twisting cycles as well as high thermal stability during thermal cycling and soaking up to 350 °C. The aerosol jet printing and photonic sintering pave the way for facile and efficient fabrication of a broad range of flexible sensors and electronics.