Synthesis and thermoelectric characterization of high density Ag2Te nanowire/PMMA nanocomposites

Insights in the two-step synthesis of single crystalline Ag2Te nanorods

“…Similarly, nearly stoichiometric Ag2.04Te nanowires were obtained by Yang et al for nAg(I)/nTe = 3 but in presence of a reducing agent and the nanowires they obtained were polycrystalline [9]. Kim et al also observed that a large excess of Ag (value not specified in their work) is needed to reach Ag2.13Te in a two-step synthesis in the presence of EG [20]. In our work, the resulting nanostructured film appear to be homogeneous on the surface as shown by the SEM image (Fig.…”

“…From these observations, the following mechanism can be proposed. The transformation of Te into Ag2Te occurs in two steps: a transformation by chemical cementation, during which Ag(I) is reduced by Te (reaction (1)), followed by a topotactic transformation implying Ag atoms entering the Te structure (reaction (2)) [14], [20]. From our observations, only a slight excess of Ag in the Ag2Te nanostructures is observed even if the molar ratio of precursors (n(Ag(I))/n(Te)) is superior to the stoichiometric ratio 4/3 according to the equation (3).…”

“…-A two-step synthesis [9], [11], [13]- [15], [19], [20], can be alternatively conducted, where either Te or Ag (nanostructures or films) is first obtained and further converted into Ag2Te by a redox reaction [11] whose mechanism is not well known until now. This two steps method allows preserving the crystallinity and the purity of the Te nanorods.…”

“…Different parameters influence the composition, the crystalline quality and the morphology of Ag2Te like bath temperature, time of reaction, Ag(I):Te molar ratio, addition of a Reducing Agent (RA) and the RA:Ag(I) molar ratio. In most cases EG is used, playing both roles of solvent and Ag(I) reducing agent and avoids the formation of byproducts [20]. Only Jao et al [11] and Samal et al [19] synthesized Ag2Te nanowires without any addition of a reducing agent.…”

Toward High-Power Output of Generators: High-Power-Factor Ag2Te–Ag Thermoelectric Thin Films Using a Layer-by-Layer Method

“…Thus, a high power factor can be expected for Ag 2 Te, owing to its low effective mass. Nanosized Ag 2 Te is also an important precipitate for fabricating hybrid flexible composites, with higher Seebeck coefficients and lower thermal conductivities than both pure Ag 2 Te and organic materials. , Nevertheless, the associated power factors are very low owing to the low electrical conductivity . Controlled by the electron donors of superfluous Ag, Ag 2 Te is a promising n-type thermoelectric material with high electrical conductivity …”