Thermoelectric energy harvesters could potentially provide energy for different small electronic devices by converting temperature differences into electrical energy. An international team of researchers have investigated a thermoelectric energy harvester design based on quantum wells. Quantum wells are made of semiconducting materials, but are easier to make than quantum dots (nano-sized semiconducting crystals) and may be operated at room temperature.

Explanation of quantum wells: http://bit.ly/17gQ0cC
Read more: http://bit.ly/1fXaGJf

The image is a drawing of the proposed quantum well energy harvester, showing the central hot region in red, the quantum wells in green, and the cold electrodes in blue.