40 Years‘ Worth of Research Identifies the Key Flaw in Solar Panel Efficiency

While solar panels have long been hailed as one of the cornerstone technologies for curbing the march of climate change, their efficiency has typically been less than stellar, making progress towards climbing over the obstacles to increased performance a highly prized commodity.

The good news, however – as laid out in a recently published study – is that researchers have finally solved a 40-year-old mystery which could bring about a real breakthrough in solar panel technology.

As it turns out, the 2 per cent efficiency drop (called Light-Induced Degradation, or LID) that solar cells often exhibit during the first several hours of use is likely down to a material defect in the silicone which forms a key part of the cell.

An absolute 2 per cent efficiency drop might seem trifling, and yet, considering the multiplying number of solar panels installed at solar farms around the world, solving the riddle could supplement the grid with many gigawatts of energy, thereby further reducing the need for non-renewable resources.

To illustrate, the amount of energy lost due to LID roughly corresponds to the total amount of energy that can be generated by the 15 nuclear plants located within the territory of the United Kingdom.

The reliable drop in solar cell efficiency has been found to result from ‘traps’ that form in silicone as the material heats upon exposure to sunlight. Image: Petr Kratochvil via publicdomainpictures.net, CC0 Public Domain

“Because of the environmental and financial impact, solar panel ‘efficiency degradation’ has been the topic of much scientific and engineering interest in the last four decades,” said one of the co-authors on the paper Tony Peaker from the University of Manchester in the UK.

“However, despite some of the best minds in the business working on it, the problem has steadfastly resisted resolution until now.”

By engaging an electrical and optical technique called deep-level transient spectroscopy (DLTS), the researchers discovered that reductions in the amount of power generated are caused by changes in the flow of electrons which occur as sunlight acts on, and thereby transforms, the electronic charge in the solar cells.

According to Peaker, once the discovery is confirmed, it could lead to significant gains for solar farms across the globe.

The study has been published in the Journal of Applied Physics.

Sources: study, sciencealert.com


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