Paint-on solar cells could power homes

Researchers at the University of Notre Dame have developed a ‘solar paint’ that could be slapped on the outside of a house to help generate power for the devices inside.

The ‘Sun-Believable’ paint uses semiconducting nanoparticles to produce energy – and while it’s nowhere near as efficient as the current standard, it’s inexpensive and easy to produce in large quantities.

“We want to do something transformative, to move beyond current silicon-based solar technology,” says professor Prashant Kamat, who led the research.

“By incorporating power-producing nanoparticles, called quantum dots, into a spreadable compound, we’ve made a one-coat solar paint that can be applied to any conductive surface without special equipment.”

The team achieved this using nano-sized particles of titanium dioxide, which were coated with either cadmium sulfide or cadmium selenide. The particles were then suspended in a mixture of water and alcohol to create a paste.

When the paste was brushed onto a transparent conducting material and exposed to light, it generated electricity.

“The best light-to-energy conversion efficiency we’ve reached so far is one percent, which is well behind the usual 10 to 15 percent efficiency of commercial silicon solar cells,” explains Kamat.

“But this paint can be made cheaply and in large quantities. If we can improve the efficiency somewhat, we may be able to make a real difference in meeting energy needs in the future.”

Kamat and his team also plan to study ways to improve the stability of the new material.