Thermoelectricity for IoT – A review

We are witnessing an unprecedented expansion of Internet of Things (IoT) market, whose nodes are already outnumbering human population several times. Despite the huge popularity of IoT, its further expansion is slowed down by a lack of viable power supply methods capable to replace wires or batteries. Due to IoT demand for alternative supply, energy harvesting (EH) gathers attention from scientific groups all around the world. In particular, thermoelectricity (TE) seems to be a natural and intuitive candidate for IoT owing to magnitude and omnipresence of heat losses and amenability to direct, vibrationless, noiseless and reliable conversion. This review provides up-to-date comparison and evaluation of a recent progress in the field of thermoelectricity, resulting primarily from multidisciplinary optimization of materials, topologies and controlling circuitry. The improvement in materials integrates two trends: nanostructural modulation of pre-existing, conventional thermoelectric materials and synthesis of novel ones. Regarding topology, TE responds better and better to miniaturization trend of semiconductor industry, driven by miniaturization trend, by proposing alternatives to conventional π-type topology. And finally, recently developed controlling circuits consume extremely low power while idle, exhibit above-90% efficiency and start-up with ultra-low input voltages. Combined, these improvements position TE closer to marketization than ever before.