RESEARCHERS say it could be possible to replace the toxic and expensive cadmium chloride used to make solar cells with a chemical used to make tofu.
Cadmium chloride is currently a key ingredient in solar cell technology, and is used to produce millions of solar panels around the world. The compound is highly toxic and expensive to produce, requiring elaborate safety measures to protect workers during manufacture. When the panels have reached end of life, they then need to be disposed by specialists.
University of Liverpool Stephenson Institute for Renewable Energy researcher Dr Jon Major says cadmium chloride can be replaced with magnesium chloride, which is extracted from seawater and is used in tofu, bath salts, and for de-icing roads.
Costing US$0.001 per gram compared to cadmium chlroide’s US$0.3 per gram, magnesium chloride has been shown in his study to be as effective as the toxic alternative.
Dr Major said cost is a major factor in the ability of renewable energy to compete with fossil fuels.
“Great strides have already been made, but the findings in this paper have the potential to reduce costs further,” he said.
The cheapest solar cells being manufactured today are based on a thin film of insoluble cadmium telluride. Alone, these cells convert less than two percent of sunlight into energy. When cadmium chloride is applied, efficiency jumps to over 15 percent.
Magnesium chloride, according to the latest research, achieves the same boost in efficiency. The difference, however, is in the method of application enabled by using a non-toxic chemical.
“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,” said Dr Major.
“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.”