High-power-density hybrid planar-type silicon thermoelectric generator with phononic nanostructures

Energy harvesting is essential for the internet-of-things networks where a tremendous number of sensors require power.Thermoelectric generators (TEGs), especially those based on silicon (Si), are a promising source of clean and sustainable energy for these sensors.However, the reported performance of planar-type Si TEGs never exceeded power factors of 0.1 -2 -2 due to the poor thermoelectric performance of Si and the suboptimal design of the devices.Here, we report a planar-type Si TEG with a power factor of 1.3 -2 -2 around room temperature.The increase in thermoelectric performance of Si by nanostructuring based on the phonon-glass electron-crystal concept and optimized three-dimensional heat-guiding structures resulted in a significant power factor.In-field testing demonstrated that our Si TEG functions as a 100-W-class harvester.This result is an essential step toward energy harvesting with a low-environmental load and cost-effective material with high throughput, a necessary condition for energy-autonomous sensor nodes for the trillion sensors universe.