Эффективная масса, подвижность носителей заряда и решеточная теплопроводность в нанокомпозитных термоэлектриках на основе халькогенидов висмута и сурьмы

In the p-type thermoelectrics based on bismuth chalcogenides and antimony with an excess bismuth, the density of states effective mass m/m0 increases in nanocomposite and nanostructured solid solutions compared with the base material obtained by the direct crystallization method. It is shown that an increase in m/m0 is associated with an increase in the effective scattering parameter reff and amplifying the relaxation time of energy, which is typical for topological insulators. The material parameter beta, proportional to the thermoelectric efficiency of ZT, at temperatures below room increases stronger in nanostructured composition than in a nanocomposite with the inclusions of SiO2 due to the growth of m/m0 and decrease the lattice thermal conductivity κL. At high temperatures in the range of 300-500 to the greatest growth of the parameter beta in the base material associated with higher mobility.

Implementation of Bismuth Chalcogenides as an Efficient Anode: A Journey from Conventional Liquid Electrolyte to an All-Solid-State Li-Ion Battery

Bismuth chalcogenide (Bi2X3; X = sulfur (S), selenium (Se), and tellurium (Te)) materials are considered as promising materials for diverse applications due to their unique properties. Their narrow bandgap, good thermal conductivity, and environmental friendliness make them suitable candidates for thermoelectric applications, photodetector, sensors along with a wide array of energy storage applications. More specifically, their unique layered structure allows them to intercalate Li+ ions and further provide conducting channels for transport. This property makes these suitable anodes for Li-ion batteries. However, low conductivity and high-volume expansion cause the poor electrochemical cyclability, thus creating a bottleneck to the implementation of these for practical use. Tremendous endeavors have been devoted towards the enhancement of cyclability of these materials, including nanostructuring and the incorporation of a carbon framework matrix to immobilize the nanostructures to prevent agglomeration. Apart from all these techniques to improve the anode properties of Bi2X3 materials, a step towards all-solid-state lithium-ion batteries using Bi2X3-based anodes has also been proven as a key approach for next-generation batteries. This review article highlights the main issues and recent advances associated with Bi2X3 anodes using both solid and liquid electrolytes.

MOCVD deposition of zinc and bismuth chalcogenides films on the surface of silica optical fibres

Metal organic chemical vapour deposition (MOCVD) technology is adapted for the deposition of thin zinc and bismuth chalcogenides films on the surface of silica optical fibres with short tapered sections. Growth runs were carried out in a special tubular quartz reactor at atmospheric pressure of hydrogen at 425°C temperature using ZnEt2, BiMe3, Et2Te and i-Pro2Se as organometallic precursors. During the deposition of chalcogenides, the transmittance spectra of the fibre were recorded in regular short time intervals. In the transmittance spectra of the fibre with a tapered section coated by ZnSe and ZnTe, lossy mode resonances (LMR) were observed at a diameter of the tapered waist below 30 μm. After the deposition of very thin Bi2Te3 and Bi2Se3 island films on the tapered waist with a diameter about 10 μm optical fibres were built into erbium fibre ring lasers. A pulsed generation mode was achieved in some of lasers due to resonator Q-factor modulation. These results can be applied for the design of LMR fibre sensors and passively Q-switch pulsed fibre lasers.

Quantum effects in electrical transport properties of Bismuth chalcogenides Topological Insulators

Quantum effects such as weak-antilocalisation (WAL) behavior and Shubnikov-de Haas (SdH) oscillations in the electrical transport properties of topological insulators, measured on nanostructured polycrystalline samples and single-crystals of a series of bismuth chalcogenide compounds (Bi2(SexTe1-x)3, 0 ≤ x ≤ 1 and BiSbTe3), are presented and discussed.