High thermoelectric performance in Sn-substituted alpha-As2Te3

作者：Vaney J B; Carreaud J; Delaizir G; Piarristeguy A; Pradel A; Alleno E; Monnier J; Lopes E B; Goncalves A P; Dauscher A; Candolfi C; Lenoir B

来源：Journal of Materials Chemistry C, 2016, 4(12): 2329-2338.

DOI：10.1039/c5tc04267d

Lead chalcogenides PbX (X = Te, Se, S) have been the materials of choice for thermoelectric power generation at mid-range temperatures (500-700 K). Here, we report on a new family of chalcogenides alpha-As2Te3 that exhibit similar thermoelectric performances near 500 K. Sn doping in p-type polycrystalline alpha-As2-xSnxTe3 (x <= 0.075) provides an efficient control parameter to tune the carrier concentration leading to thermopower values that exceed 300 mu V K-1 at 500 K. Combined with the structural complexity of the monoclinic lattice that results in extremely low thermal conductivity (0.55 W m(-1) K-1 at 523 K), a peak ZT value of 0.8 is achieved at 523 K for x = 0.05. A single-parabolic band model is found to capture well the variations in the transport properties with the Sn concentration and suggests that higher ZT values could be achieved through band structure engineering. These results surpass those obtained in the sister compounds beta-As2-xSnxTe3 and further show that alpha-As2Te3 based materials are competitive with other chalcogenides for thermoelectric applications at intermediate temperatures.

• 出版日期2016