Flexible Temperature Sensor Array Based on PEDOT:PSS Inkjet Printing

Inkjet-printed micro-electro-mechanical systems are a set of fabrication techniques that use inexpensive printed circuit processes to construct microsensors. Compared with traditional sensors, flexible micro-sensors present excellent application prospects in the fields of medical electronics, environmental monitoring wearable devices, etc. This article developed a simple flexible temperature sensor array based on inkjet-printed micro-electro-mechanical systems by using poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS) as the sensing material. This sensor array employed polyethylene terephthalate (PET), nine silver contact electrodes, and 12 PEDOT:PSS sensing blocks as the bottom substrate, middle layer, and top layer, respectively. There are 12 temperature sensors arrayed on an area of
$4\times 4$
cm2, which can realize a thermal resolution of
$5\times 5$
temperature pixels using the modeling simulation method. The sensor array showed a sensitivity of -0.50%/°C with a small hysteresis from 25 up to
$75~^{\circ }$
C (or in a chosen temperature range), which is higher compared to that of other similar sensors reported in the literature. To improve the accuracy, an array correction algorithm was investigated as a data processing method and succeeded in reducing the temperature error from 0.80% to less than 0.50%. The combination of the array and flexible structures makes our temperature-sensing arrays easy to affix and particularly advantageous for displaying interface heat diffusion behavior, such as the water body’s epidermis.