There’s a new way of getting solar energy; paint your house and you’ll be tapping solar energy in your house. Researchers have come up with a potential giant hi-tech ‘sun trap’ made from nanocrystals so small they can exist as a liquid ink and be painted or printed onto clear surfaces.
In an effort to find an alternative to silicon-based solar cells, the Notre Dame researchers turned to quantum dot materials. They started with nanoparticles of titanium dioxide (TiO2) and coated them with either cadmium sulfide or cadmium selenide – both compounds that can absorb photons. A photon of the right energy hitting the cadmium compounds causes an electron to escape, which is absorbed by the TiO2.
The resultant particles (about four nanometers in size- meaning you could fit more than 250,000,000,000 on the head of a pin) were then suspended in a water-alcohol mixture to create a paste. The cadmium sulfide mixture produced a yellow paste, while the cadmium selenide mix produced a dark brown. The most efficient was a mixture of the two that produced a light brown paste.
With a relatively low-temperature process, the researchers’ method also allows for the possibility that solar cells can be printed onto plastic instead of glass without any issues with melting — resulting in a flexible solar panel that can be shaped to fit anywhere.
The Liquid nanocrystal solar cells are cheaper to fabricate than available single-crystal silicon wafer solar cells but are not nearly as efficient at converting sunlight to electricity.