Template-free solvothermal synthesis and enhanced thermoelectric performance of Sb2Te3 nanosheets

A simple template-free solvothermal approach has been developed for the fabrication of Sb2Te3 thermoelectric materials. Single-crystalline Sb2Te3 nanosheets are 200–300 nm in edge lengths and only 18–20 nm thick. The nanosheets with no residual organics were hot pressing sintered (HPS) to a p-type nanostructured bulk material, and it still consisted of Sb2Te3 nanosheets after HPS and thermoelectric (TE) properties measurements. Relatively good TE properties have been achieved in the Sb2Te3 nanosheet sintered bulk sample from 320 K to 565 K: high electrical conductivity σ (1.69–2.30) × 104 Ω−1 m−1, high Seebeck coefficient S (173–199 μV K−1) and low thermal conductivity κ (0.66–0.82 W m−1 K−1). Consequently, the dimensionless thermoelectric figure of merit (ZT) of 0.57 at 565 K was achieved. Meanwhile, the maximum in ZT was shifted significantly to higher temperature.

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► Sb2Te3 hexagonal nanosheets were synthesized by a simple template-free solvothermal approach.
► The nanosheets were hot pressing sintered to a nanostructured bulk material for thermoelectric measurements.
► The Sb2Te3 nanosheet sintered bulk sample shows higher Seebeck coefficient and lower thermal conductivity.