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

Konsolide SnSe Parçacıklarından CdSe-SnSe Nanokompozitlerinin Üretimi

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.

Yazar Spotlight: İşlenmiş Termoelektrik Malzemeler Olarak Nanokompozitleri Kullanarak Enerji Çözümlerini Geliştirme

Çözelti işlenmiş, yüzey mühendisliği, düşük ısı iletkenliği sergileyen polikristal CdSe-SnSe

Our group focused on developing materials for energy-related applications, emphasizing energy storage and thermal electricity. We used nano crystals as building blocks, or precursors for constructing the microscopic materials. And we investigate the transformation the nano crystals undergo into whole solids, aiming to enhance performance, and by understanding and controlling the properties derived from the nanoscale features.In particular, for thermal electric materials, we focused on defect control. Developing thermoelectric materials via solution processing involves numerous challenges. One, mitigating oxidation due to the nanoparticles'high surface to volume ratio.Reproducibility, due to the complexity of the process. And three, dealing with volatile species to ensure stability. Addressing and understanding these challenges is crucial for enhancing thermal electric materials efficiency for practical applications.Our research advanced cost-effective solution-processed thermal electric materials, by fine-tuning nanoparticle properties and their organization. We are uncovering the chemistry involved in the whole process, from the nanoparticle synthesis to the final consolidation. And currently, we are focused on how surface species or affect materials microstructure, and hence their performance.We enhanced thermoelectric performance through the utilizing solution process surface engineered particles, significantly reducing the thermal conductivity by micro structural tuning and the introduction of defects. This approach also is advantageous, because it uses inexpensive precursors, low temperatures, and also, we use water as a solvent. We found that certain molecules absorb at the particle surface and restrict grain growth.Now, we are trying to rationalize how different surface species affect microstructure and hence transport properties, based on their composition, chemical instability, and bonding nature.

CdSe-SnSe Nanokompozitlerinin Üretimi için SnSe Partiküllerinin Sentezi

Başlamak için, argon gazını beş dakika boyunca sıcak kalay çözeltisi ile üç boyunlu bir şişenin üzerine yerleştirilmiş bir ayırma hunisinden geçirin. Kauçuk septumu selenyum çözeltisi içeren bir şişeden çıkarın ve çözeltiyi ayırma hunisi yoluyla kalay çözeltisine aktarın. Karışımı 101 santigrat dereceye ısıtın ve iki saat karıştırın.Karıştırırken şişeyi bir su banyosuna yerleştirin. Karışım soğuduktan sonra, şişeyi Schlenk hattından yuvarlak tabanlı bir şişe desteğine aktarın. Şimdi beş dakika bekletildikten sonra 600 mililitre süpernatan dökün.Kalan ham çözeltiyi dört santrifüj tüpüne bölün. Süpernatanı santrifüjleyin ve ardından atın. Süpernatanı attıktan sonra her tüpün içeriğini 40 mililitre deiyonize su ile vorteksleyin.Bunu takiben, karışımı beş dakika boyunca bir sonikasyon banyosunda sonikleştirin. Sonra tekrar girdap ve santrifüjleyin. Daha sonra, çökeltiyi 40 mililitre etanol ile yıkayın.Altıncı yıkamadan sonra, tüpleri en az 12 saat boyunca vakum altında kuruyan bir yere koyun. Çökelti kuruduktan sonra, tüpleri nitrojen dolu bir torpido gözüne aktarın. Bir akik havan ve havaneli ile 10 selenit parçacığını ince bir toz haline getirin.Tozun dört gramını 20 mililitrelik bir şişeye aktarın. Hazırlanan kadmiyum-selenyum-metilformamid karışımını 48 saat boyunca sürekli karıştırarak bu şişeye ekleyin. Kadmiyum-selenyum yüzey işlem görmüş partikülleri saflaştırmak için, karışımı santrifüjleyin ve süpernatanı atın.Sonra 40 mililitre susuz etanol ekleyin. Süpernatanı attıktan sonra, kadmiyum-selenyum ile muamele edilmiş parçacıkları kurusu içinde 12 saat boyunca vakum altında kurutun, ardından ince bir toz elde etmek için kurutulmuş tozu torpido gözünde öğütün.

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

Research

JoVE Journal

Chemistry

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

290 Görüntüleme.  Institute of Science and Technology Austria (ISTA). Başlamak için, argon gazını beş dakika boyunca sıcak kalay çözeltisi ile üç boyunlu bir şişenin üzerine yerleştirilmiş bir ayırma hunisinden geçirin. Kauçuk septumu selenyum çözeltisi içeren bir şişeden çıkarın ve çözeltiyi ayırma hunisi yoluyla kalay çözeltisine aktarın. Karışımı 101 santigrat dereceye ısıtın ve iki saat karıştırın.Karıştırırken şişeyi bir su banyosuna yerleştirin. Karışım soğuduktan sonra, şişeyi Schlenk hattın...

Video: CdSe-SnSe Nanokompozitlerinin Üretimi için SnSe Partiküllerinin Sentezi

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 ...