Planar-type silicon thermoelectric generator with phononic nanostructures for 100 {\mu}W energy harvesting

TL;DR

This paper presents a silicon thermoelectric generator with enhanced performance using nanostructuring and optimized design, achieving 100 μW energy harvesting suitable for IoT sensors.

Contribution

The study introduces a planar-type silicon TEG with a significantly improved power factor of 1.3 μWcm^{-2}K^{-2} through phononic nanostructures and optimized heat-guiding, enabling practical energy harvesting.

Findings

Achieved a power factor of 1.3 μWcm^{-2}K^{-2} at room temperature.

Demonstrated a 100-μW-class energy harvester in field tests.

Enhanced thermoelectric performance of silicon via nanostructuring.

Abstract

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 ${\mu} Wcm^{-2} K^{-2}$ 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 ${\mu} Wcm^{-2} K^{-2}$ 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-${\mu}W$-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.