Introduction
Thermoelectric materials have been around since the late 18th century when Seebeck discovered that when two different metals are connected in a circuit, a current flow is produced when one of them is maintained at a different temperature. Since then, researchers have been exploring the properties of thermoelectric materials to find ways in which they can be used in applications such as energy harvesting, cooling and power generation. Recently, there has been an increased interest in thermoelectric materials due to their potential for efficient energy conversion with minimal environmental impact.
Fundamentals of Thermoelectric Materials
Thermoelectric materials are semiconductor materials that are capable of exhibiting the Seebeck effect. When certain materials are maintained at two different temperatures, a voltage differential can be measured across them. This phenomenon is known as the Seebeck effect and is used in thermoelectric generators and coolers.
The ability of thermoelectric material to transfer energy between different temperatures is due to its unique semiconductor properties. These materials are composed of semiconductor elements such as bismuth telluride, silicium germanium or tin-doped indium oxide and either doped or undoped materials. Depending on the composition, these materials can exhibit either a positive or negative Seebeck coefficient.
Thermoelectric materials can also exhibit another effect known as the Peltier effect. When two different materials are connected in a circuit and subjected to a current flow, the temperature at one of the materials will decrease due to the heat being transferred from one material to the other.
The performance of a thermoelectric material is usually measured by its figure of merit (ZT). This parameter is used to compare different types of materials and takes into consideration the Seebeck coefficient, electrical resistivity and thermal conductivity of the material.
Applications of Thermoelectric Materials
Thermoelectric materials find a wide range of applications in the form of thermoelectric generators, coolers and other energy-saving devices. Thermoelectric generators introduce a voltage differential between two different materials when they are subjected to different temperatures. This voltage can be used to generate electricity when connected to a load. These generators have been used as an alternate source of power in many remote areas or have been used to recover energy in the form of heat from exhaust systems of automobiles.
Thermoelectric coolers are devices used for cooling applications. They use a Peltier effect to cool one side of the device and dissipate the heat at the other side. They have been used to cool electronic chips, food and beverages and other materials.
Due to their efficiency in energy conversion, thermoelectric material can also be used for power generation. Solar-thermal plants and geothermal-power plants are examples of such applications.
Conclusion
Thermoelectric materials are semiconductor materials capable of exhibiting the Seebeck effect. They have a wide range of applications, from thermoelectric generators and coolers to solar and geothermal power plants. These materials are highly efficient in energy conversion and can be used in various fields to maximize energy production while minimizing energy consumption.
