With fossil fuels being both polluting and limited, authorities and scientists worldwide have shifted their gaze on generating electrical power from alternate sources. One such source is Electricity from waste heat. A recent breakthrough discovery in this direction is a super-small device made from silicon which has been made at Sandia National Laboratories.
The device can capture and transform waste heat into electrical power. While converting electrical energy into heat is easy, doing the opposite can prove to be tricky. But this is exactly what the new device does. It gathers waste heat from places such as car engines to change it into DC power. The details of the process was published in Physical Review Applied.
How Electrical Power from Waste Heat Works
Vis-à-vis size, the device is 1/8 square inch. This makes it half as thick as dime and as shiny as a metal. The top part is aluminum that is etched with stripes. The stripes are almost 20 times narrower than the width of human hair. Those serve as antenna.
While the top part is made of aluminum, the bottom part is made of a wafer-thin layer of silicon dioxide. It is almost 16,000 times thinner than a strand of human hair! Infrared radiation is funneled onto it by the etched aluminum antenna. It is then trapped in the silicon dioxide to generate oscillations of almost 50 trillion times per second. In the process, electrons are pushed back and forth between the aluminum and silicon in an asymmetric manner. This is called rectification and it helps generate DC electrical current.
The device is called rectenna by the team that built it. This is because it is akin to a rectifying antenna for capturing infrared radiation.