Progress and Perspective: Soft Thermoelectric Materials for Wearable and Internet-of-Things Applications

Soft thermoelectric materials, including conjugated polymers and organic-inorganic hybrids, now demonstrate figures of merit approaching those of inorganic materials. These materials development breakthroughs enable the design of thermoelectric devices that exhibit appropriate efficiencies for commercial use, while simultaneously leveraging the unique processing and mechanical advantages of soft materials. Such a technology opens the door to a suite of new thermoelectric applications, including power generation for biomedical implants and the Internet of Things, or wearable heating and cooling devices. In order to realize deployment of such technologies, there is a fundamental need for deeper understanding of the complex transport physics underlying thermoelectric transport in soft materials. Here, the current state of the art in soft thermoelectrics materials is discussed, and outstanding challenges specific to organic and organic-inorganic hybrid systems are highlighted.