Термоелектричне матеріалознавство і нанотехнології. Практика та теорія

Abstract

Прогрес у галузі термоелектрики вимагає подальшого розвитку матеріалознавства углиб речовини завдяки використанню прикладних і теоретичних здобутків нанотехнологій, зокрема нанотермодинаміки. Це дає змогу розширити спектр чинних термодинамічних сил з урахуванням сил, притаманних наноструктурованим речовинам, та підвищити ефективність залучення концепції вихрових термоелектричних струмів для точнішого вимірювання температури термоелектричними сенсорами. Проведені дослідження матеріалів термоелектричних сенсорів охоплюють не лише вивчення стабільності термо-ЕРС, але й вивчення їх методами неруйнівного акустичного контролю. Це дає змогу оцінити й розвинути роль специфічних механізмів формування вихрових термоелектричних струмів у дрейфі термо-ЕРС.

Progress in the field of thermoelectricity requires the further development of material science deep into the substance through the use of the achievements of applied and theoretical advances in nanotechnologies, including nanothermodynamics. This enables to expand the range of current thermodynamic forces, taking into account the forces inherent in nanostructured substances, and to increase the efficiency of attracting the concept of eddy thermoelectric currents in order to increase the accuracy of temperature measurement by thermoelectric sensors. The researches of materials of thermoelectric sensors have not only included not only the study of the stability of thermoelectric sensors, but their study by their methods of nondestructive acoustic control. This makes it possible to assess and develop the role of specific mechanisms for the formation of eddy thermoelectric currents in the drift of thermoelectric power. According to the results of acoustic studies of thermometric materials of thermoelectric sensors, the possibilities of their characterization were revealed in a non-destructive way. The influence of micro and nanostructural effects on the formation of local eddy thermoelectric currents as the source of thermoelectric power is evaluated. Taking into account thermodynamic forces and flows inherent in nanostructured thermoelectric materials, it becomes possible to modify the concept of local eddy thermoelectric currents concerning the enhancement of the accuracy of temperature measurement. The mechanism of currents formation due to the effect of coherence in nanostructured materials is studied. Here minimal temperature changes lead to the appearance of currents. On the other hand, the similar mechanism caused by the gradient of mechanical stresses raises. The latter permits the modification of thermoelectric materials by forming multidimensional fields of elastic micro stresses that can be especially effective for nanostructured thermoelectric materials. Eddy thermoelectric currents, for which a temperature gradient is required, can be considered a partial case of a much broader class of eddy electrical currents occurring in an electrically conducting substance under the influence of fluctuations in thermodynamic parameters. The stability of thermoelectric power, as well as its magnitude, can be substantially enhanced in nanostructured materials by the direct formation of gradients of thermodynamic parameters, different from the temperature gradient.