Enhanced Thermal Sensitivity of Graphite Paint-Based Flexible Thermocouple

Thermocouples are used in a variety of applications for temperature measurement and monitoring. Here, we demonstrate an HB/6B graphite paint-based thermocouple to design temperature sensors on commercially available Xerox paper using two different grades of graphite. The difference in Seebeck coefficients in different grades of graphite facilitates the successful fabrication of a thermocouple. These simple, cheap, environment friendly, biodegradable single-material thermocouples demonstrated a persistent and reliable sensitivity of ~ 27 μV/K after 300 bending cycles. In addition, the output voltage variation has also been recorded after 300 bending cycles as a function of time to demonstrate response with respect to temperature. The current study indicates that a piece of paper can be transformed into a thermal mapping device using only graphite paint patterns.