Professor Mildred S. Dresselhaus from the Massachusetts Institute of Technology has brought back to life the old idea of designing materials that could be used for controlling temperatures, with extremely efficient electronic devices similar to the photovoltaic cells and electronic devices. The material works in efficient ways, heating up or cooling only the necessary area, without producing excess heat or cold which would be wasted, thus saving large amounts of energy.

Similar devices have been produced at MIT in the 1960s, based on the principle of thermoelectric cooling and heating discovered in the early 19th century. The Thermoelectric effect represents the direct conversion of temperature differences into electrical power and vice versa. Meaning when a thermoelectric device has applied different temperatures on each side it creates a voltage and when a voltage is applied to each side, it experiences temperature differences. The effect currently has multiple applications from measuring devices to cool objects.

The thermoelectric material presents a series of effects that make them work in these ways, the Seebeck effect, through which heat is directly transformed into electricity, the Peltier effect which represents the reverse of the Seebeck effect and the Thomson effect which states the direction in which the electric current will flow, in relation to the temperature differences.

There are a variety of such thermoelectric materials from which thermoelectric devices can be made of, such as bulky metallic junctions, or semiconductor p-n junctions. But while these materials are able to convert heat into electricity and vice versa, they have a major drawback, since they are notoriously inefficient.

The problem of creating efficient thermoelectric materials is that they need to be extremely good at conducting electrical current, but not heat, so while they get hot on a side and cold on the other, they remain this way, instead of quickly equalizing the temperatures. Most of the materials known to man have electrical and thermal properties which are synchronized, meaning if the material is a good electricity conductor it will also conduct heat very well.

According to Dresselhaus, the key in creating materials that have offset electrical and thermal properties was in designing an engineered semiconductor material, in which nanostructures would alter the way the base material behaves, affecting the way heat travels but leaving the electrical properties unchanged.

The same principle used to heat up certain objects with the help of the thermoelectric materials could provide a new solution for microchips producers, to cool the processors with cooling systems incorporated in the chip itself.

The current engines which equip most of the cars are extremely inefficient, converting more than 80 percent of the fuel into unnecessary heat, which goes to waste. Thermoelectric systems could potentially recuperate the energy and convert it into useful electrical energy.

Semiconductor thermoelectric material could also offer a solution to the problem of creating more efficient photovoltaic cells, by harnessing the sunlight and the sun heat at the same time, to create electricity.