Omni-Thermoelectrics: Atomically Convertible p/n Nanowire Inks for Flexible Generators

Thermoelectric devices possess enormous potential to reshape the global energy landscape by converting waste heat into electricity, yet their commercial implementation has been limited by their high cost to output power ratio. No single “champion” thermoelectric material exists due to a broad range of material-dependent thermal and electrical property optimization challenges. While the advent of nanostructuring provided a general design paradigm for reducing material thermal conductivities, there exists no analogous strategy for homogeneous, precise doping of materials. Here, we demonstrate a nanoscale interface engineering approach that harnesses the large chemically accessible surface areas of nanomaterials to yield massive, finely-controlled, and stable changes in the Seebeck coefficient, switching a prototypical p-type thermoelectric material, tellurium, into a robust n-type material exhibiting stable properties over months of testing. These remodeled, n-type nanowires display power factors comparable to their p-type counterparts, and are partnered together to demonstrate the first solution-processed, monomaterial flexible thermoelectric generators. We proceed further to dope these nanowires with small organic molecules to generate hybrid organic inorganic nanocomposites and demonstrate power factors and ZTs surpassing bulk tellurium.