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Solvothermal synthesis and thermoelectric properties of indium telluride nanostring-cluster hierarchical structures.

Tai G, Miao C, Wang Y, Bai Y, Zhang H, Guo W - Nanoscale Res Lett (2011)

Bottom Line: A simple solvothermal approach has been developed to successfully synthesize n-type α-In2Te3 thermoelectric nanomaterials.A diffusion-limited reaction mechanism was proposed to explain the formation of the hierarchical structures.The synthetic route can be applied to obtain other low-dimensional semiconducting telluride nanostructures.PACS: 65.80.-g, 68.35.bg, 68.35.bt.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Nanoscience, Nanjing University of Aeronautics and Astronautics, 29 Yudao Street, Nanjing 210016, People's Republic of China. taiguoan@nuaa.edu.cn.

ABSTRACT
A simple solvothermal approach has been developed to successfully synthesize n-type α-In2Te3 thermoelectric nanomaterials. The nanostring-cluster hierarchical structures were prepared using In(NO3)3 and Na2TeO3 as the reactants in a mixed solvent of ethylenediamine and ethylene glycol at 200°C for 24 h. A diffusion-limited reaction mechanism was proposed to explain the formation of the hierarchical structures. The Seebeck coefficient of the bulk pellet pressed by the obtained samples exhibits 43% enhancement over that of the corresponding thin film at room temperature. The electrical conductivity of the bulk pellet is one to four orders of magnitude higher than that of the corresponding thin film or p-type bulk sample. The synthetic route can be applied to obtain other low-dimensional semiconducting telluride nanostructures.PACS: 65.80.-g, 68.35.bg, 68.35.bt.

No MeSH data available.


A schematic of the formation mechanism of the In2Te3 hierarchical structures.
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Figure 8: A schematic of the formation mechanism of the In2Te3 hierarchical structures.

Mentions: In the reaction system, acetaldehyde is produced by dehydration of EG at high temperature, as shown in Equation 1. The EG acted as both solvent and reductant in this case, and ions were reduced by EG to form elemental Te at the beginning of the reaction, which is shown in Equation 2. The reaction (2) was a quick step, which determined the formation of t-Te nanowires at the beginning of the reaction. The EDA plays an important role in the transformation process from the t-Te nanowires to the hierarchical In2Te3 nanowires because strongly basic solvents, such as ammonia and EDA, can reduce Te into Te2- with a low speed (Equation 3). This leads to the formation of nanoporous structures on the surface of the nanowires (Figure 5b, c); meanwhile, a complex is formed by the reaction of the solvent EDA molecule and the metal In3+ ions. In this complex, each In3+ is surrounded by six NH2 group, similar to Co3+ [34]. Although In3+ is combined with the t-Te and reduced into indium by the EDA in situ near the surface of the template t-Te nanowires at high temperature and high pressure, as Equation 4, In3+ has little solubility in EDA at room temperature and atmosphere [35]. Thus, indium atoms can quickly diffuse into the t-Te nanowires. With increasing the reaction duration, the molar ratio of In:Te is close to the stoichiometric composition of In2Te3 (Figure 4b). The transformation mechanism of the t-Te nanowires to the In2Te3 hierarchical structures is shown in Figure 8.


Solvothermal synthesis and thermoelectric properties of indium telluride nanostring-cluster hierarchical structures.

Tai G, Miao C, Wang Y, Bai Y, Zhang H, Guo W - Nanoscale Res Lett (2011)

A schematic of the formation mechanism of the In2Te3 hierarchical structures.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211416&req=5

Figure 8: A schematic of the formation mechanism of the In2Te3 hierarchical structures.
Mentions: In the reaction system, acetaldehyde is produced by dehydration of EG at high temperature, as shown in Equation 1. The EG acted as both solvent and reductant in this case, and ions were reduced by EG to form elemental Te at the beginning of the reaction, which is shown in Equation 2. The reaction (2) was a quick step, which determined the formation of t-Te nanowires at the beginning of the reaction. The EDA plays an important role in the transformation process from the t-Te nanowires to the hierarchical In2Te3 nanowires because strongly basic solvents, such as ammonia and EDA, can reduce Te into Te2- with a low speed (Equation 3). This leads to the formation of nanoporous structures on the surface of the nanowires (Figure 5b, c); meanwhile, a complex is formed by the reaction of the solvent EDA molecule and the metal In3+ ions. In this complex, each In3+ is surrounded by six NH2 group, similar to Co3+ [34]. Although In3+ is combined with the t-Te and reduced into indium by the EDA in situ near the surface of the template t-Te nanowires at high temperature and high pressure, as Equation 4, In3+ has little solubility in EDA at room temperature and atmosphere [35]. Thus, indium atoms can quickly diffuse into the t-Te nanowires. With increasing the reaction duration, the molar ratio of In:Te is close to the stoichiometric composition of In2Te3 (Figure 4b). The transformation mechanism of the t-Te nanowires to the In2Te3 hierarchical structures is shown in Figure 8.

Bottom Line: A simple solvothermal approach has been developed to successfully synthesize n-type α-In2Te3 thermoelectric nanomaterials.A diffusion-limited reaction mechanism was proposed to explain the formation of the hierarchical structures.The synthetic route can be applied to obtain other low-dimensional semiconducting telluride nanostructures.PACS: 65.80.-g, 68.35.bg, 68.35.bt.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Nanoscience, Nanjing University of Aeronautics and Astronautics, 29 Yudao Street, Nanjing 210016, People's Republic of China. taiguoan@nuaa.edu.cn.

ABSTRACT
A simple solvothermal approach has been developed to successfully synthesize n-type α-In2Te3 thermoelectric nanomaterials. The nanostring-cluster hierarchical structures were prepared using In(NO3)3 and Na2TeO3 as the reactants in a mixed solvent of ethylenediamine and ethylene glycol at 200°C for 24 h. A diffusion-limited reaction mechanism was proposed to explain the formation of the hierarchical structures. The Seebeck coefficient of the bulk pellet pressed by the obtained samples exhibits 43% enhancement over that of the corresponding thin film at room temperature. The electrical conductivity of the bulk pellet is one to four orders of magnitude higher than that of the corresponding thin film or p-type bulk sample. The synthetic route can be applied to obtain other low-dimensional semiconducting telluride nanostructures.PACS: 65.80.-g, 68.35.bg, 68.35.bt.

No MeSH data available.