Energy from Exhaust

The scientist from Washington state university, Prof. Yi Gu, invented in the field of thermoelectric, the use of converted heat to generate alternative forms of energy.

          The device is multicomponent, multilayered composite material called “van der Waals Schottky Diode”. This device converts heat into electricity upto three times more efficient than silicon.

          In 1820 Thomas Johann Seebeck discovered that temperature difference between two dissimilar electrical conductor or semiconductor are in contact produce electromotive force or voltage, this is because change in temperature causes electron to jump from hot side to cold side and form current. This effect is called SEEBECK EFFECT.

          In electronics world, Schottky diodes are used to guide electricity in a specific direction, similar to how a valve in a water main directs the flow of liquid going through it. They are made by attaching a conductor metal like aluminum to a semiconductor material like silicon.

          Instead of combining a common metal like aluminum or copper with a conventional semiconductor material like silicon, this device is made from material of microscopic crystalline indium selenide. When you attach a metal to a semiconductor material like silicon to form a Schottky diode, there are always some defects that form interference, this imperfection trap electrons impending the flow of electricity. Gu’s diode is unique in that it’s surface does not appear to have any defects. This lower resistance to the device makes it much more energy efficient.

The scientist has used simple heating process used heatingprocess used to modify one layer of indium selenide to act as a metal and another layer to act as a metal and another layer to acts as a semiconductor. In future, one layer of this diode could be attached to something hot surface like car exhaust and another to a surface at room temperature. The diode would than use the heat difference between two surfaces to create an electric current that could be stored in battery and used when needed.

          Gu and his collaborators are currently working on new methods to increase the efficiency of their Indium Selenide crystals. They are also working towards exploring ways to synthesize larger quantities of the material so that it can be developed into useful devices.

          “While still in the preliminary stages, our work represents a big leap forward in the field of thermoelectrics,” Gu said. “It could play an important role in realizing a more energy efficient society in the future.”