As well as being a relatively rare and valuable metal, silver is the world’s most efficient and cost-effective conductor of heat and electricity.
That’s why it’s routinely used in photovoltaic (PV) solar cells (commonly known as solar panels) and why it’s important to be able to recover and recycle as much as possible.
As well as being used in new solar panels, silver can be redeployed in a wide range of biomedical devices and other useful applications.
The average solar panel of two square metres can use up to 20 grams of silver, but current methods of recovering the metal are inefficient and environmentally harmful.
The most common method involves the use of nitric acid to break down the silver for recovery.
Now, researchers at the University of Virginia (UVA) are using what they say is a greener, more efficient method involving a process known as laser ablation.
This means removing some material from a solid surface using intense laser light.
In this case, the silver electrical contact material of the PV cells will be converted into nanoparticles.
After extraction, this silver can be used in new silicone modules with no further refinement required, or it can be purified for other uses.
UVA engineering professor Mool Gupta is heading the project, which is backed by a $250,000 (£208,000) grant from the US Department of Energy.
It is part of a wider $6m effort to seed small, innovative projects in the fields of solar-thermal technologies.
New approach could encourage greater recycling of solar panels
Prof Gupta said that the new technology could represent a greener and more efficient method of recovering silver from old solar panels, prompting manufacturers and recyclers to get more use out of them.
Solar panels typically have a useful life of up to 25 years, and they are not generally refurbished beyond that because of costs.
They then tend to go to a glass recycling facility, where the glass and sometimes frames may be recovered while other elements are disposed of.
Solar panel and module waste is predicted to reach 78 million tons by 2050, and it has been difficult so far to compete with the environmentally harmful landfill approach due to costs.
The researchers are hoping that their new approach may change that.
Professor Scott Acton, chair of UVA’s Electrical and Computer Engineering Department, said that the innovative use of laser ablation represented an important step in achieving “clean, sustainable, and inexpensive energy sources for the future”.
Today’s news was brought to you by TD SYNNEX – the UK’s number one solutions distributor.
