Silicon as a key material for Low-temperature Heat Harvesting and Thermal Management

Silicon is the most widely used functional material and, as such, it enjoys a fantastic technology. It is also geo-abundant and non-toxic. Unfortunately, its efficiency as a thermoelectric material is known to be very poor, unless strategies are deployed to decrease its thermal conductivity. Alloying with Ge and nanostructuration went into this direction, making it the reference material for radioisotope thermoelectric generators. Lately, silicon has also emerged as a candidate for the low-temperature range, where its usability as thin film fully harnesses its easy integrability and the available body of technological know-how. In this talk, recent advances of research on silicon and related materials for low-temperature thermoelectric applications will be presented, comparing the two current strategies to increase its performances, namely reducing its thermal conductivity and, in polycrystalline materials, increasing its power factor. It will be then shown how Si-based thermoelectric generators and coolers are excellent runners-up for microharvesting and localized thermal management around room temperature –a key enabling technology for applications ranging from the Internet of Things to healthcare support and monitoring.