Overview of thermoelectric materials technology

Overview of thermoelectric materials technology
Thermoelectric material (also called thermoelectric material, thermoelectric materials) is a kind of functional material which uses the internal carrier motion of solid to realize the direct conversion of heat energy and electric energy.
In 1834, the French physicist Pelte discovered the thermoelectric effect, will be connected to the conductor of different materials, and through the current, the contact point of the different conductors - nodes, will absorb or emit heat. In 1838, Russian physicist Lenz made more visibility experiment: using metal bismuth and antimony form when the current node along one direction through the nodes, the nodes in the water will solidify into ice; if the reverse current direction, cemented on node of ice will melt into the water immediately.
Although the scientific community found on Pell McNair Lenz very seriously, but because of the metal thermoelectric conversion efficiency is very low, the discovery is not quickly into practical application. It was not until 1950s that some semiconductor materials with excellent thermoelectric conversion performance were found. Thermoelectric refrigeration and thermoelectric power generation technology became a hot research topic.
Development of thermoelectric power generation technology
What is the use of thermoelectric power generation, waste heat, waste heat steam, waste heat, solar heat such as heat, and thermoelectric power larger features, using a thermal effect (first Sebek effect, or Seebeck effect), convert heat directly into a way of generating electricity.
Two different types of thermoelectric conversion material N and P is combined with one end and the other end of the high temperature condition, and give open at low temperature due to the high temperature end of the heat stimulation is strong, electron and hole concentration than the low temperature end in this high, the carrier concentration gradient, hole and electron diffusion to low end to the open end of temperature, forming potential in low temperature. If a plurality of groups of P type and N type thermoelectric materials are connected to form a module, a sufficiently high voltage can be obtained to form a thermoelectric generator.
According to the classification of the use of heat sources, thermoelectric generator can be divided into radioisotope thermoelectric generator, nuclear reactor thermoelectric generator, hydrocarbon fuel thermoelectric generator, low thermal thermoelectric generator, etc.. While the lower heat thermoelectric generator, the various forms of low temperature heat (including heat heat) directly into electrical energy conversion thermoelectric generator, the hot surface temperature is generally below 400 DEG C, typical thermoelectric materials are using bismuth telluride (Bi2Te3). In addition, there are two kinds of low dimensional thermoelectric materials has good application prospect, one is CsBi4Te6, which is actually the interstitial Bi2Te3, the other is a selenium (Se) doped HfTe5 in the temperature range of T<220K, the Seebeck coefficient is far beyond the Bi2Te3.

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