Гальваномагнитные свойства и термоэдс ультратонких пленок системы висмут--сурьма на подложке из слюды

The study of the electronic properties of ultrathin films of pure bismuth and bismuth-antimony alloys is of interest, since an increase in conductivity with decreasing sample thickness was found. This paper presents the results of an experimental study of the structure, electrical, galvanomagnetic and thermoelectric properties of pure bismuth and Bi1−x Sbx thin films (x = 0.05 and 0.12) on a mica substrate in the thickness range of 10−30 nm. An increase in the conductivity with a decrease in the thickness of the samples was found. It may be due to the presence of topologically protected surface states. It is shown that the features of the manifestation of this effect are significantly influenced by the alloys band structure. The form of the temperature dependences of the Seebeck coefficient casts doubt on the fact that surface states have a positive effect on the thermoelectric efficiency of thin bismuth-antimony films. However, the detection of a positive thermoelectric power in Bi0.88Sb0.12 samples can become an important factor for searching for the possibility of creating a p-branch of thermoelectric converters.

Simulation of Photovoltaic Thermoelectric Battery Characteristics

Solar radiation is an environmentally friendly and affordable energy source with high release of energy. The use of a photovoltaic thermoelectric battery makes it possible to increase the efficiency of converting solar and thermal radiation into electrical energy, both on serene and cloudy days. An original battery structure with photovoltaic and thermoelectric converters is proposed. The 3D model of the proposed photovoltaic thermoelectric battery was realized in the COMSOL Multiphysics software environment with the use of a heat transfer module. The simulation was performed for the geographical coordinates of Minsk and taking into account the diurnal and seasonal variations of both the ambient temperature and the power density of the concentrated AM1.5 solar spectrum, the maximum value of which being varied from 1 to 500 kW/m2. The dependences of the maximum temperature values of the photovoltaic thermoelectric battery and the thermoelectric converters as well as temperature gradient patterns in the thermoelectric converters have been calculated. The dependences of the maximum temperature gradient values inside the thermoelectric converters on the solar power density are obtained. The graphs of the temperature gradients inside the thermoelectric converters of the photovoltaic thermoelectric battery by concentrated solar radiation versus the time of day in the middle of July and January are provided. It is shown that the output voltage increases up to the maximum values of 635 and 780 mV, respectively, in January and in July were achieved due to the temperature stabilization of the back side of the external electrodes of the proposed device

Extruded material based on Bi0.85Sb0.15 for thermoelectric converters

In order to create a sufficiently strong material with thermo- and magneto-thermoelectric figure of merit close to single-crystal samples of material based on Bi-Sb systems, extruded samples of Bi0.85Sb0.15 solid solution were obtained and the effect of composition, heat treatment mode, grain size and tellurium impurities was investigated on their thermoelectric properties in the temperature range ~ 77-300 K and magnetic field strength H up to ~ 74∙104A/m. We managed to obtain extruded material with thermo- and magneto-thermoelectric figure of merit ~6.2∙10-3 K-1 and ~7.2∙10-3K-1 at ~ 77 K, respectively, with strengths ~ 3 times higher than the strength of single-crystal samples of this composition, which are suitable for use in low-temperature thermoelectric converters.

Обнаружение термовольтаического эффекта в гетероструктуре на основе теллурида свинца

The thermovoltaic effect was detected in a heterostructure based on a semiconductor material used in medium-temperature thermoelectric converters (PbTe). A voltage of ~0.015 V was generated at constant temperature T = 390 K. At T = 732 K, the voltage was 0.11 V.

XVI Международная конференция "Термоэлектрики и их применения --- 2018" (ISCTA 2018), Санкт-Петербург, 8-12 октября 2018 г. Новое направление применения термоэлектрических преобразователей энергии

In southern countries, including European states, solar collectors for additional water-heating systems are widely used. However, the disadvantage of such systems is that a considerable proportion of solar energy cannot be used with increasing water temperature and dissipates into the environment. It is proposed to use waste heat at a high temperature, which is supplied to a thermoelectric generator (TEG) operating on the basis of a temperature difference between the hot water in the solar collector and cold water supplied to a radiator on the other TEG side. This is a new application of thermoelectric converters, in which the converter can act not only as a source of electrical energy but also as a source of low-potential heat coming from the radiator. The total conversion efficiency in such devices can reach 90%. It is shown that the use of p -type legs in a TEG with the cleavage planes of the legs parallel to the heat-flux direction instead of the conventional parallel orientation results in an increase in the thermoelectric efficiency by 25% on average in the temperature range of 100–300°C.

Composite Thermoelectric Materials Based on Lead Telluride and Cadmium Telluride

The results of the researching of thermoelectric properties of samples, which are obtained by compression mechanical mixtures of micro dispersed powders PdTe and CdTe, are presented. It was found that the use of cadmium for telluride as an additional component to the lead telluride contributes to a decrease in the coefficient of thermal conductivity of the materials of the studied system, which can be promising for the creation of thermoelectric converters based on them.