Harness solar energy with salt, spray-on cells

Magnesium chloride, used to make tofu and found in bath salt, can be used in solar panels to bring down their cost and cut toxic waste

 
By Moushumi Sharma
Published: Saturday 04 July 2015

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Solar energy is witnessing major breakthrough. As solar panels gain popularity around the world, scientists have discovered a way to produce solar cells with edible salts which is not only cheaper but also less toxic.

A new study finds that magnesium chloride when added to solar cells can produce solar power as efficiently as conventional cadmium cells, but at a fraction of the cost and with much lower toxicity, reports The Guardian, a newspaper published in Lagos, Nigeria. The study was carried out by researchers from the University of Liverpool, England, and was published in the journal Nature. 

According to the report, about 90 per cent of the solar panels currently in use are made of photovoltaic cells composed of silicon semiconductors, which convert sunlight directly into electricity. But since silicon is not good at absorbing sunlight, the solar cells have a thin coating of cadmium telluride, which absorbs sunlight very well. It is of critical importance to activate cadmium telluride with cadmium chloride in the manufacturing process, which makes the latter potentially dangerous. The scientists wanted to find an alternative to cadmium chloride in the activation phase. They found that magnesium chloride does the job just as well.

Cost-effective replacement
Magnesium chloride is found abundantly in sea water and is used in bath salts and coagulation of soya milk into tofu. “Cadmium chloride is toxic and expensive, and we no longer need to use it. 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,” lead researcher Jon Major told The Guardian. He added that magnesium chloride is incredibly low-cost and is simply recovered from seawater. “We have managed to replace a highly expensive, toxic material with one that is completely benign and low cost,” he added, estimating that the salt is about one per cent of the cost of cadmium chloride. “In addition, waste disposal will be far easier with a product based on a non-toxic salt,” he said.

Turn anything into solar cell
In another interesting development, scientists from the University of Sheffield, England, have created low-cost, spray-on solar cells that can be applied to surfaces like paint or graphic printing, reports The Daily Mail. The cells are made of a material called perovskite—used to describe the mineral crystal structure found in the calcium titanium oxide mineral species. With this technology, anything from cars to clothes sprayed with perovskite can be used to harness solar energy.

Experts have hailed this development as a major step forward. The spray can be mass produced, has low manufacturing cost and produces little waste. “There is a lot of excitement around perovskite-based photovoltaics. Remarkably, this class of material offers the potential to combine the high performance of mature solar cell technologies with the low-embedded energy costs of production of organic photovoltaics,” lead researcher David Lidzey told The Daily Mail. 

Its efficiency, however, is under scrutiny. Perovskite was first used for solar cells in 2009, but its efficiency was found to be low. According to Lidzey, perovskite cells now have an efficiency rate of up to 19 per cent.

 

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