Let’s Know about Bismuth Telluride Thermoelectric Material

Thermoelectric materials are used in thermoelectric device for generating cooling and heating effects. The most common uses of these materials are to regenerate the electricity from waste heat at electric power plants. These are available as per high strength or low cost materials. The low cost materials which have strong sufficient thermoelectric effect are used in applications including power generations and refrigeration. We mostly use in such applications bismuth telluride (Bi₂Te₃) thermoelectric material.

Basically for manufacturing high quality thermoelectric module, the selection of thermoelectric material is affected by several factors such as:

·        Electrical Conductivity

·        Thermal Conductivity

·        Seebeck Coefficient

·        Temperatures Change Behavior

 After choosing a material its usefulness is decided by the material’s power factor and device efficiency.

As most of the company use high-efficiency material Bi₂Te₃ and high temperature solders for generating thermoelectric modules, so we discuss about this in detail.

Bismuth Telluride (Bi₂Te₃):

It is a grey powder which is compounded from bismuth and tellurium. We also know this as bismuth (lll) telluride. For portable power generation and refrigeration we alloy this thermoelectric material with antimony and selenium in a semiconductor. It is also known as topological insulator and hence exhibits many thickness dependent physical properties.

Why use as thermoelectric material?

Bismuth telluride has a thin gap layered semiconductor which has trigonal unit cell. Due to van der waals bonding, it cleaves easily along with trigonal axis between neighboring tellurium atoms. Because of this feature we always use polycrystalline bismuth telluride (Bi₂Te₃) for power generation and cooling applications. Apart from this, the Seebeck coefficient of bismuth telluride metal becomes compensated around the room temperature. Due to which it is forced to be used in power generating devices and having the alloy of bismuth, antimony, tellurium and selenium.

As bismuth telluride thermoelectric material and its solid solutions are good at room temperature, hence, it is also suitable for refrigeration applications around 300 K. A method named Czochralskiis used to grow single crystalline bismuth telluride compounds. These compounds are produced with directional solidification from melt or powder metallurgy processes. The produced material has superior mechanical properties and sensitive to structural defects and lower impurities due to high optimal carrier concentrations.For more information visit @ http://ferrotec-nord.com/support/thermoelectric-modules