An Ultralow-Power Flexible Thermal Flow Sensor Based on Electrochemical Impedance

For the first time, we report an Electrochemical Impedance (EI) based ultrathin and low-power Flexible Thermal Flow (FTF) sensor using MEMS technology. For the 0.9% NaCl solution flow, the fabricated 7.4 μm thick FTF sensor achieved a normalized sensitivity of 19.53 PPM/(μm/s)/mW with respect to the input heating power, which is twice better than previously reported EI flow sensors. Besides, tested in 0~400 μm/s flow, the FTF sensor gains a LOD of 6.2 μm/s with an ultralow heating power of < 8.6 mW. Therefore, our EI-based FTF sensor will be able to reliably and accurately measure ultra-low physiological fluid flow in the future.