Graphene-Enhanced Screen-Printed BiFeO₃-Based Thermistors

Abstract

In this study, serigraphic-grade BiFeO3-based ink formulations are produced and \nthen mixed with graphene to enhance the performances of screen-printed thermistor \ndevices. The devices are printed atop a standard thermally-boosted glass-reinforced \nepoxy (FR-4) substrate coated with interdigitated gold electrodes. The broader operating \ntemperature range of these thermistors makes them compatible with standard \nprinted circuit boards (PCBs) manufacturing and operating conditions. Thus, we \nachieve highly-sensitive devices with a temperature coefficient of resistance (TCR) of \n-0.96 %/°C, which is the highest sensitivity reported yet for any graphene-based thermistor \noperating from 25 to 170 °C. The best performing devices are loaded with 3.5 \nwt.% graphene. These low-hysteresis and stable thermistors boast a thermal index (β- \ncoefficient) of 864 K. This optimal graphene loading occurs just above the percolation \nthreshold.