Heat is energy, and wasted heat is wasted energy. Reliable and compact devices capable of a direct conversion of heat into electrical power are of paramount importance for the recovery of large amounts of heat that is currently wasted because there is not an available technology to recover it.
We develop devices, based on silicon which is cheap and biocompatible, that exploit nanostructuration to achieve an efficient thermal-to-electrical conversion efficiency.
These devices can be both:
1) integrated on-chip, for the wireles and battery-free supply of sensor nodes (scavenging);
2) fabricated on large surfaces (several dm^2) with cheap and affordable techniques, for the recovery of large amounts of wasted heat generated by many productive cycles, such as those of paper factories, steel foundries, chemical manufacturers and so on.
In the figure (from G.Pennelli, E.Dimaggio, A.Masci, “Silicon Nanowires: a Breakthrough for Thermoelectric Applications”, Materials 14, 5305,2021, Open Access) : scanning electron microscope images of a on-chip thermoelectric device, based on a large collection of silicon nanostructures. It can generate electrical power exploiting an hot surface, for the wireless and battery-free supply of a sensor node (for IoT or Industry 4.0 applications).
The sketch shows the the heat flow into the device, that produces an output power through the electrical contacts.