Morphology-Engineered Nanostructured Silver- and Antimony-Telluride Films for Flexible Thermoelectric Generators

Harvesting low-grade heat to produce electricity is attractive for powering wearable electronic devices. Here, we demonstrate nW-scale thermoelectric power generation in devices from thin-film assemblies of microwave-synthesized p-Sb2Te3 nanoplates and n-Ag2Te nanowires on polyvinylidene fluoride (PVDF) membranes. While microwave cycling is crucial for Ag2Te nanocrystal shaping, and Sb2Te3 formation is sensitive to precursors and surfactant concentrations. Introducing S doping in Sb2Te3 in the 1 ≤ xS ≤ 1.5 at. % range via thioglycolic acid during synthesis yields an up to 8-fold higher power factor, due to a 5-fold increase in electrical conductivity and ∼25% increase in the Seebeck coefficient. Our microfilm devices generate up to 33.6 mV from 5 °C ≤ ΔT ≤ 50 °C thermal gradients, with ∼120 nW maximum power output at ΔT = 30 °C, which is 60-fold higher than Sb2Te3 paper devices. Mechanical bending can increase device resistance by up to ∼125% due to diminished internanostructure electronic transport. These findings provide insights for integrating synthesis, morphology engineering, and device design for next-generation wearable thermoelectric systems.