synthesis of snse particles for the production of cdse&#45;snse nanocomposites

从固结 SnSe 颗粒生产 CdSe-SnSe 纳米复合材料

Thermoelectric (TE) materials, which convert heat into electricity and vice versa, can play an important role in sustainable energy management1. However, the low conversion efficiencies combined with the relatively high production costs of these materials have limited their broad application for industrial and domestic use. To overcome present challenges, cost-effective synthetic methods and the use of abundant and non-toxic materials with significantly improved efficiency must be implemented.
The thermoelectric figure of merit zT= S2&#963;T/&#954;, where S is the Seebeck coefficient, &#963; the electrical conductivity, T the absolute temperature, and &#954; the thermal conductivity, determines the efficiency of these materials. Due to the strong coupling of these properties, maximizing zT is a challenge. It often entails tuning the electronic band structure and microstructural defects to control charge and phonon scattering mechanisms2,3,4,5.
In the last decade, tin selenide (SnSe) has been explored as a non-toxic thermoelectric material due to its outstanding performance in its single crystal form (zT: p-type ~2.6, n-type ~2.8)6,7. However, single crystals are expensive to produce, limiting their applicability to devices. Alternatively, polycrystalline SnSe is cheaper to produce and mechanically more stable. The problem is that attaining high performance presents difficulties due to partial loss of anisotropy, diminishing electrical conductivity, greater ease of oxidation, and imprecise control of the doping level8,9,10.
Polycrystalline inorganic TE materials are usually processed in two steps: preparation of the semiconductor in powder form followed by consolidation of the powder into a dense pellet. Powders can be prepared through high-temperature reactions and grinding or directly by ball-milling11,12,13,14,15,16. Alternatively, powders can be synthesized via solution methods (e.g., hydrothermal, solvothermal, aqueous synthesis), requiring less demanding conditions (i.e., lower reagent purity, lower temperatures, and shorter reaction times)17,18,19,20,21.
This paper describes a method to produce dense SnSe nanocomposites from surface-modified SnSe particles that are synthesized in water. The process commences from the aqueous synthesis of SnSe particles, where reducing agents and bases are used to solubilize the Se and Sn reagents, respectively. When the solutions are combined, SnSe particles immediately start precipitating. After purification, SnSe particles are then functionalized with CdSe molecular complexes. During the annealing process, the molecular complexes decompose; forming CdSe nanoparticles19. The presence of CdSe nanoparticles inhibits grain growth and promotes the formation of many defects at varying length scales. These scattering sources result in low thermal conductivity and a high thermoelectric figure of merit22.

作者聚焦：使用纳米复合材料作为加工热电材料推进能源解决方案

溶液处理、表面工程、多晶 CdSe-SnSe，具有低导热性

SnSe颗粒的合成用于生产CdSe-SnSe纳米复合材料

首先，将氩气通过放置在装有热锡溶液的三口烧瓶上的分离漏斗五分钟。从装有硒溶液的烧瓶中取出橡胶隔膜，并通过分离漏斗将溶液转移到锡溶液中。将混合物加热至 101 摄氏度，搅拌两小时。将烧瓶放入水浴中，同时搅拌。混合物冷却后，将舒伦克管路中的烧瓶转移到圆底烧瓶支架上。现在，在沉淀五分钟后倒出 600 毫升上清液。将剩余的粗溶液分装到四个离心管中。离心，然后弃去上清液。弃去上清液后，用 40 毫升去离子水涡旋每个管的内容物。之后，在超声处理浴中对混合物进行超声处理五分钟。然后再次涡旋并离心。接下来，用 40 毫升乙醇洗涤沉淀物。第六次洗涤后，将试管置于真空干燥器中至少 12 小时。沉淀物干燥后，将试管转移到充满氮气的手套箱中。用玛瑙研钵和研杵，将 10 个硒化物颗粒研磨成细粉。将 4 克粉末转移到 20 毫升小瓶中。将准备好的镉 - 硒 - 甲基甲酰胺混合物加入该小瓶中，不断搅拌48小时。为了纯化镉 - 硒表面处理的颗粒，将混合物离心并丢弃上清液。然后加入40毫升无水乙醇。弃去上清液后，将经镉硒处理的颗粒在真空干燥池中干燥12小时，然后在手套箱中将干燥的粉末研磨，得到细粉。

synthesis-snse-particles-for-production-cdse-snse

Research

JoVE Journal

Chemistry

Synthesis of SnSe Particles for the Production of CdSe&#45;SnSe Nanocomposites

297 次观看. 首先，将氩气通过放置在装有热锡溶液的三口烧瓶上的分离漏斗五分钟。从装有硒溶液的烧瓶中取出橡胶隔膜，并通过分离漏斗将溶液转移到锡溶液中。将混合物加热至 101 摄氏度，搅拌两小时。将烧瓶放入水浴中，同时搅拌。混合物冷却后，将舒伦克管路中的烧瓶转移到圆底烧瓶支架上。现在，在沉淀五分钟后倒出 600 毫升上清液。将剩余的粗溶液分装到四个离?...

视频: SnSe颗粒的合成用于生产CdSe-SnSe纳米复合材料

Solution&#45;Processed, Surface&#45;Engineered, Polycrystalline CdSe&#45;SnSe Exhibiting Low Thermal Conductivity

In recent years, solution processes have gained considerable traction as a cost-effective and scalable method to produce high-performance thermoelectric materials. The process entails a series of critical steps: synthesis, purification, thermal treatments, and consolidation, each playing a pivotal role in determining performance, stability, and reproducibility. We have noticed a need for more comprehensive details for each of the described steps in most published works. Recognizing the significance of detailed synthetic protocols, we describe here the approach used to synthesize and characterize one of the highest-performing polycrystalline p-type SnSe. In particular, we report the synthesis of SnSe particles in water and the subsequent surface treatment with CdSe molecular complexes that yields CdSe-SnSe nanocomposites upon consolidation. Moreover, the surface treatment inhibits grain growth through Zenner pinning of secondary phase CdSe nanoparticles and enhances defect formation at different length scales. The enhanced complexity in the CdSe-SnSe nanocomposite microstructure with respect to SnSe promotes phonon scattering and thereby significantly reduces the thermal conductivity. Such surface engineering provides opportunities in solution processing for introducing and controlling defects, making it possible to optimize the transport properties and attain a high thermoelectric figure of merit.

CdSe-SnSe nanocomposites are produced by consolidating surface-engineered SnSe particles. A simple aqueous synthesis is employed to produce SnSe particles. Coating SnSe particles with CdSe molecular complexes allows for controlling grain size and increasing the number of defects present in the nanocomposite, thus lowering the thermal conductivity.

In recent years, solution processes have gained considerable traction as a cost-effective and scalable method to produce high-performance thermoelectric ...