n-Type Ultrathin Few-Layer Nanosheets of Bi-Doped SnSe: Synthesis and Thermoelectric Properties
n-Type Ultrathin Few-Layer Nanosheets of Bi-Doped SnSe: Synthesis and Thermoelectric Properties
复制标题
DOI：
10.1021/acsenergylett.8b00399
复制
发表时间：
2018-05-01
影响因子：
22
通讯作者：
Biswas, Kanishka
中科院分区：
文献类型：
--
作者：
Chandra, Sushmita;Banik, Ananya;Biswas, Kanishka
SnSe是一种环保的层状硫族化物，以其单晶的高热电品质因数引起了热电界的广泛关注。尽管开发优质 p 型 SnSe 作为热电材料的步伐正在迅速进展，但 n 型 SnSe 的合成在某种程度上被忽视了。在这里，我们报告了二维（2D）超薄（1.2-3 nm 厚）少层纳米片（2-4 层）n 型 SnSe 的溶液相合成和热电传输特性。纳米片的 n 型性质最初源于合成过程中材料的氯化。通过进一步的Bi掺杂，我们可以将n型SnSe的载流子浓度从3.08 X 10(17)显着提高到1.97 X 10(18) cm(-3)，从而提高电导率和功率因数。此外，Bi掺杂纳米片在300-720 K的温度范围内表现出超低晶格热导率（类似于0.3 W/mK），这可归因于SnSe层界面、纳米级晶界和点缺陷的有效声子散射。
SnSe, an environmentally friendly layered chalcogenide, has fostered immense attention in the thermoelectric community with its high thermoelectric figure of merit in single crystals. Although the stride toward developing superior p-type SnSe as a thermoelectric material is progressing rapidly, synthesis of n-type SnSe is somewhat overlooked. Here, we report the solution-phase synthesis and thermoelectric transport properties of two-dimensional (2D) ultrathin (1.2-3 nm thick) few-layer nanosheets (2-4 layers) of n-type SnSe. The n-type nature of the nanosheets initially originates from chlorination of the material during the synthesis. We could increase the carrier concentration of n-type SnSe significantly from 3.08 X 10(17) to 1.97 X 10(18) cm(-3) via further Bi doping, which results in an increase of electrical conductivity and power factor. Furthermore, Bi-doped nanosheets exhibit ultralow lattice thermal conductivity (similar to 0.3 W/mK) throughout the temperature range of 300-720 K, which can be ascribed to the effective phonon scattering by an interface of SnSe layers, nanoscale grain boundaries, and point defects.