n型SnS热电材料的制备与性能研究

SnS由低毒、廉价、高丰度的元素组成, 在热电研究领域受到广泛关注。采用机械合金化(MA)结合放电等离子烧结(SPS)工艺制备了n型SnS_1-xCl_x(x=0, 0.02, 0.03, 0.04, 0.05, 0.06)多晶块体热电样品, 并研究了Cl^-掺杂量对SnS物相、微观结构以及电热输运性能的影响。结果表明: Cl^-的引入会提高电子浓度, 使SnS由本征p型转变为n型半导体。随着Cl^-掺杂量的增加, n型SnS半导体室温下的霍尔载流子浓度从6.31×10¹⁴ cm^-3 (x=0.03)增加到7.27×10¹⁵cm^-3 (x=0.06)。x=0.05样品在823 K取得最大的电导率为408 S·m^-1, 同时具有较高的泽贝克系数为-553 μV•K^-1, 使其获得最大功率因子为1.2 μW·cm^-1·K^-2。Cl^-的掺入会引入点缺陷, 散射声子, 使晶格热导率κ_lat由0.67 W·m^-1·K^-1(x=0)降至0.5 W·m^-1·K^-1 (x=0.02)。x=0.04样品在823 K获得了最大ZT为0.17, 相比于x=0样品(ZT~0.1)提高了70%。

Preparation and Thermoelectric Property of n-type SnS

SnS composed of low toxicity, low-cost and earth-abundant elements, has extensive attention in the field of thermoelectric research. The n-type SnS_1-xCl_x (x=0, 0.02, 0.03, 0.04, 0.05, 0.06) polycrystalline bulk thermoelectric samples were prepared by mechanical alloying (MA) combined with Spark Plasma Sintering (SPS). Effect of Cl^- amounts on the phase structure, microstructure and thermoelectric transport properties were systematically studied. Results show that introduction of Cl^- enhances electron concentration which makes intrinsic p-type SnS change to n-type. With the amount of Cl^- increasing, the Hall carrier concentration of n-type SnS semiconductor increases from 6.31×10¹⁴cm^-3 (x=0.03) to 7.27×10¹⁵cm^-3 (x=0.06) at room temperature. The maximum electrical conductivity of 408 S•m^-1 the relatively high Seebeck coefficient of -553 μV•K^-1 are obtained at 823 K for x=0.05 sample, which produces the maximum power factor of 1.2 μW·cm^-1·K^-2. Addition of Cl^- can introduce point defects to scatter phonons, which makes the lattice thermal conductivity reduce from 0.67 W·m^-1·K^-1 (x=0) to 0.5 W·m^-1·K^-1 (x=0.02). The highest ZT~0.17 is obtained at 823 K for x=0.04 sample, which is 70% higher than that (ZT~0.1) of the pristine SnS.