Seebeck effect, also known as the first thermoelectric effect, refers to the thermoelectric phenomenon of the voltage difference between two substances caused by the temperature difference between two different electrical conductors or semiconductors. Generally, the direction of thermoelectric potential is: electrons flow from negative to positive at the hot end.
In the circuit composed of two metals A and B, if the temperature of the two contact points is different, the current will appear in the circuit, which is called thermal current. The corresponding electromotive force is called thermoelectromotive force, and its direction depends on the direction of temperature gradient.
The cause of Seebeck effect can be simply explained as the carrier in the conductor moves from the hot end to the cold end under the temperature gradient, and accumulates in the cold end, so as to form the potential difference in the material. At the same time, under the effect of the potential difference, a reverse ncharge flow is generated. When the ncharge flow of thermal movement and the internal electric field reach a dynamic balance, a stable thermoelectric potential is formed at both ends of the semiconductor. The thermoelectromotive force of semiconductor is large, so it can be used as thermoelectric generator.