A recent study by researchers from the School of Engineering at Macquarie University has demonstrated the effectiveness of using microwave radiation as a means of heating during the solar cell manufacturing process.

This new method offers several benefits over the traditional oven-based approach, including increased efficiency, reduced energy consumption, and improved recyclability.

Specifically, the technique streamlines the annealing process – a key step in solar panel production – which typically involves subjecting silicon cells to high temperatures.

The unique ability of microwave radiation to selectively heat silicon results in rapid and energy-efficient heating, as the other materials that make up the laminated panel (glass, plastic, and aluminum) remain mostly unaffected.

Microwaves’ annealing ability to selectively heat materials makes the process highly precise and customizable.

The use of microwave technology in the solar cell manufacturing process has also resulted in recycling benefits. Specifically, the ethylene vinyl acetate plastic coating that protects the silicon plate during the process softens under microwave treatment, allowing it to be mechanically peeled off.

This means that the plate can be easily separated into its components and recycled without the need for harsh chemicals, making the process more environmentally friendly.

Prior to the development of this new technology, it was more economically viable to dispose of old solar panels in landfills rather than recycle them.

In cases where recycling did occur, the panels would typically be crushed and subjected to a high-temperature process of around 1400°C, followed by a chemical treatment to remove the plastic coating. This process was extremely energy-intensive and not cost-effective.

However, as the first generation of solar panels installed about 20-30 years ago are now reaching the end of their lifespan and being decommissioned, governments are increasingly pressured to recycle them.

The microwave technology developed by the team offers a more sustainable and energy-efficient solution to this problem.

This is particularly useful for newer solar panels that incorporate heterojunction technology, where crystalline and amorphous silicon are layered together. In these cells, the ability to direct and speed up annealing is especially advantageous.

Additionally, microwave annealing can be carried out at room temperature, eliminating the need for high-temperature furnaces, further reducing energy consumption, and making the process more sustainable.

The study was conducted in collaboration with the School of Photovoltaics at the University of New South Wales (UNSW) and was originally supported by funding from the Australian Centre for Advanced Photovoltaics. The project has since received additional support from the Australian government through the Australian Renewable Energy Agency (ARENA).

Researchers at the Fraunhofer Institute for Solar Energy Systems have developed a solution that combines power from renewable sources with electricity from the public grid and uses batteries to compensate for fluctuations.

Earlier this month, researchers at the Shandong Academy of Medical Sciences, China, and Kyushu Institute of Technology, Japan, claimed to upcycle crab shells into porous, carbon-filled materials with various uses, including using the crab carbon to create anode materials for sodium-ion batteries.