Efficient fabrication and characterization of doped nanocomposites for thermoelectric materials

Abstract

The development of ultrahigh-temperature thermoelectric materials has the potential to accelerate the expansion of direct thermoelectric power generation. The current limitation on thermoelectric operation temperatures, which has been under 1500 K, is mainly owing to a lack of suitable materials. We describe a novel thermoelectric conversion material made from high-temperature reduced graphene oxide-based nanosheets that demonstrates constant performance up to 800 K. The method used here to synthesize graphene oxide sheets decorated with Ag₂Te and (Bi_0.5Na_0.5)TiO₃ (BNT) powders formed exhibited a high Seebeck coefficient and a decent figure of merit. A thin film of RGO-doped bismuth telluride and Ag₂Te was deposited onto FTO (Fluorine-doped Tin Oxide) glass by spin coating for positive(p) and BNT for negative (n-type) materials. Field Electron Scanning electron microscopy (FESEM), XRD, TEM, Raman, and FTIR were also used to study the microstructure and chemical composition. Our findings point to using binary oxides doped with oxides to create low-cost thermoelectric materials that operate at low (ambient room) temperatures and potentially benefit energy harvesting systems. For the first time, our report showed the figure of merit around 1.8 × 10^–4 K^-1 in the temperature range 700–800 K.