Benchtop Room-Temperature Synthesis of High Performance Thermoelectrics

Se-containing materials often synthesized by solution-assisted from toxic and expensive organo-Se precursors. We are reporting a facile alternative utilizing elemental Se which is cheap and non-toxic. Elemental Se reagent has a drawback of low solubility and reactivity resulting in sluggish kinetics at low temperatures. A process of elemental Se activation was developed resulting in stable solution of multiple Se species confirmed with ⁷⁷Se NMR studies, including R-Se-Se-R and never detected before “naked” Se₂^2–. Dynamic equilibrium between the produced Se species allow to perform reactions at wide temperature ranges including room temperature. The developed activated Se precursor allows us to produce Ag₂Se-based materials at room temperature thus avoiding the high-temperature polymorphic phase transitions during the synthesis. The produced materials exhibit flat, almost temperature-independent zT in the 300-400 K range with average zT’s exceeding 1.