Printed nanotechnology solar cells could dramatically reduce costs

(Nanowerk News) Printable, flexible solar cells that could dramatically decrease the cost of renewable energy have been developed by University of Melbourne PhD student Brandon MacDonald in collaboration with his colleagues from University of Melbourne's Bio21 Institute and the CSIRO's Future Manufacturing Flagship.
Their patented technology is based on inks containing tiny, semiconducting nanocrystals, which can be printed directly onto a variety of surfaces.
By choosing the right combination of ink and surface it is possible to make efficient solar cells using very little material or energy. The solar cells can be used much like current solar panels to provide power to things like lighting on bus shelters.
"The problem with traditional solar cells," Brandon says, "is that making them requires many complex and energy intensive steps."
"Using nanocrystal inks, they can be manufactured in a continuous manner, which increases production rate and should make the cells much cheaper to produce."
Nanocrystals, also known as quantum dots, are semiconducting particles with a diameter of a few millionths of a millimetre. Because of their extremely small size they can remain suspended in a solution.
This solution can then be deposited onto a variety of materials, including flexible plastics or metal foils. It is then dried to form a thin film. Brandon and his colleagues discovered that by depositing multiple layers of nanocrystals they can fill in any defects formed during the drying process.
The result is a densely packed, uniform film, ideal for lightweight solar cells.
The nanocrystals consist of a semiconducting material called cadmium telluride, which is a very strong absorber of light. This means that the resulting cells can be made very thin.
"The total amount of material used in these cells is about 1 per cent of what you would use for a typical silicon solar cell. Even compared to other types of cadmium telluride cells ours are much thinner, using approximately one-tenth as much material," Brandon says.
The technology is not limited to solar cells. It can also be used to make printable versions of other electronic devices, such as light emitting diodes, lasers or transistors.
For his work Brandon has received the 2010/11 DuPont Young Innovator's Award and has had his work published in the journal Nano Letters ("Solution-Processed Sintered Nanocrystal Solar Cells via Layer-by-Layer Assembly").
Source: University of Melbourne