Synthesis and DC Electrical Conductivity of Nanocomposites Based on Poly(1-vinyl-1,2,4-triazole) and Thermoelectric Tellurium Nanoparticles

Abstract

In this work, the structural characteristics and DC electrical conductivity of firstly synthesized organic–inorganic nanocomposites of thermoelectric Te0 nanoparticles (1.4, 2.8, 4.3 wt%) and poly(1-vinyl-1,2,4-triazole) (PVT) were analyzed. The composites were characterized by high-resolution transmission electron microscopy, X-ray diffractometry, UV-Vis spectroscopy, and dynamic light scattering analysis. The study results showed that the nanocomposite nanoparticles distributed in the polymer matrix had a shape close to spherical and an average size of 4–18 nm. The average size of the nanoparticles was determined using the Brus model relation. The optical band gap applied in the model was determined on the basis of UV-Vis data by the Tauc method and the 10% absorption method. The values obtained varied between 2.9 and 5.1 nm. These values are in good agreement with the values of the nanoparticle size, which are typical for their fractions presented in the nanocomposite. The characteristic sizes of the nanoparticles in the fractions obtained from the Pesika size distribution data were 4.6, 4.9, and 5.0 nm for the nanocomposites with percentages of 1.4, 2.8, and 4.3%, respectively. The DC electrical conductivity of the nanocomposites was measured by a two-probe method in the temperature range of 25–80 °C. It was found that the formation of an inorganic nanophase in the PVT polymer as well as an increase in the average size of nanoparticles led to an increase in the DC conductivity over the entire temperature range. The results revealed that the DC electrical conductivity of nanocomposites with a Tellurium content of 2.8, 4.3 wt% at 80 °C becomes higher than the conventional boundary of 10−10 S/cm separating dielectrics and semiconductors.

The Use of Polysaccharide Matrices as a Basis for the Formation of Tellurium Nanoparticles with Different Morphologies

“…[ 69 , 70 , 71 ]. We also used this system for the synthesis of zero-valent spherical Te 0 NPs stabilized by synthetic copolymer of poly(1-vinyl-1.2.4-triazole) [ 30 ]. However, the formation of zero-valent Te 0 NPs in matrices of galactose-containing polysaccharides with investigation of the influence of the type of polysaccharide and synthesis conditions on the nanomorphological characteristics of the obtained nanoparticles is described for the first time in this work.…”

“…In these cases, the synthesis of nanoparticles is based on the oxidation of Te anions to the zero-valent state, including with the involvement of various oxidizing agents [ 28 ]. Elemental powder Te can also be used for the synthesis of Te 0 NPs only after its preliminary activation (e.g., in the systems NaBH 4 -NH 4 OH or NaOH-N 2 H 4 -H 2 O) [ 29 , 30 ].…”