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Tofu ingredient could clean up solar cell recipe


June 29, 2014

Dr Jon Major says magnesium chloride could replace toxic cadmium chloride in CdTe solar cells without impacting efficiency

Dr Jon Major says magnesium chloride could replace toxic cadmium chloride in CdTe solar cells without impacting efficiency

Tofu has long been touted as a good way to clean out your insides, but now a researcher at the University of Liverpool says an ingredient in tofu could also be used to clean up solar cells. The hope is that the naturally occurring substance could replace a key ingredient in thin film solar cells that is highly toxic and expensive to produce.

Conventional manufacture of thin film solar cells requires sophisticated safety measures to protect workers from the hazards presented by cadmium chloride, a key ingredient in thin film solar cell technology. Additionally, once the solar cells have reached the end of their life, specialist disposal is required to deal with the highly toxic soluble compound.

Despite these shortcomings, its benefit is improved solar efficiency. By applying it to the cheapest kind of solar cells that are based on a thin film of insoluble cadmium telluride (CdTe), conversion efficiency jumps from under two percent to over 15 percent.

Now, Dr Jon Major, a physicist working at the University of Liverpool's Stephenson Institute for Renewable Energy, says cadmium chloride could be replaced by magnesium chloride, a compound that can be extracted from seawater and already has a wide variety of applications. These include, being used for de-icing roads, as a fertilizer, as a mineral supplement for animals, in fire extinguishers and acting as a coagulant in the preparation of tofu from soy milk.

Adding to the long list of uses, Major claims that magnesium chloride can produce the same boosts in conversion efficiency as provided by cadmium chloride, while being much safer.

"We have to apply cadmium chloride in a fume cupboard in the lab, but we created solar cells using the new method on a bench with a spray gun bought from a model shop," says Major.

Additionally, Major says magnesium chloride is much cheaper, costing US$0.001 per gram compared to $0.3 per gram for cadmium chloride.

"Cadmium chloride is toxic and expensive and we no longer need to use it," adds Major. "Replacing it with a naturally occurring substance could save the industry a vast amount of money and reduce the overall cost for generating power from solar."

Dr Major's study is published in the journal Nature.

Source: University of Liverpool

About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag. All articles by Darren Quick

Fine work Dr Jon Major! Though it does strike me as strange that when they were first dabbling with CdCl2 wouldn't have explored other avenues. I'm guessing that there is a little more to it than "replacing" with MgCl2

Craig Jennings

It would not matter if it costs the same price - at least it is not endangering workers!

The Skud

I agree with The Skud, paying the same price sounds agreeable when it means safer working conditions.

I have a feeling many would rather use Tofu / parts of Tofu for this instead of having to eat it. :)

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