Unlocking microwatt power: enhanced performance of Fe–V–Al thin films in thermoelectric microgenerators

Microwatt power output was obtained in thermoelectric microgenerators based on cost-effective and non-toxic Fe–V–Al thin films deposited by a DC magnetron co-sputtering process. A maximum electrical power of almost 5 μW at a temperature difference of 134 K was measured. This result leads to a maximum power density of 58.5 ± 6 mW cm−2, which is among the highest values obtained by a microdevice. Contrary to what is observed for other thermoelectric materials like Bi2Te3 or PEDOT composites, the performances of the present devices, assembled with junctions between Fe–V–Al and aluminum electrodes, are weakly impacted by their contact resistance. These results are very encouraging for the development of new architectures based on low-resistance Fe–V–Al thin films to power autonomous sensors in the Internet of Thing domain