Thermocromic materials for temperature sensors in new applications

The development of a temperature sensor with a non-linear behavior is described in this work. The device acts like a thermal switch with hysteresis and is able to return to the initial conditions. Its on-off settings are the passage on fixed temperature that corresponds to the critical temperature (Tc) of thermocromic materials, in this case vanadium dioxide. The final aim is to modify the device switching temperature by changing the thermocromic material critical temperature, following the needs of the specific application. A critical temperature variation can be induced through a doping process with elements having a great vanadium affinity. For this application molybdenum, tungsten, niobium have been employed, and experimental samples have been realized by thin films deposition. A model of Tc variation and doping concentration has been obtained for VO2-Mo film, which good results have been obtained for, to support the programmable device development.