Renewables, Solar

Australian solar cell inventors awarded top prize from King Charles

HM King Charles III has awarded four pioneering Australians the world’s most prestigious engineering prize for their invention of PERC solar cell technology.

Dr Jianhua Zhao, Professor Andrew Blakers, Professor Martin Green and Dr Aihua Wang (pictured above, from left) have been awarded the 2023 Queen Elizabeth Prize for Engineering for their development of the solar innovation at UNSW Sydney.

Passivated Emitter and Rear Cell (PERC) photovoltaic technology has reduced the costs of solar panels by 80 per cent during the past decade. The quartet are credited for pioneering this breakthrough technology, which underpins exponential growth in high-performance, low-cost solar electricity worldwide.

King Charles presented the award at a ceremony at Buckingham Palace in London on 12 October, 2023.

During the past 40 years, Professor Green and his team’s pioneering work has transformed photovoltaic technology and significantly reduced its costs. Solar is now the cheapest source of electricity in most countries.

The lynchpin of the team’s innovation is the boosting of solar panels’ energy conversion efficiency. It was once believed that 20 per cent efficiency was the practical limit for a single-layer silicon solar cell until papers by Professor Green, Professor Blakers, Dr Wang and Dr Zhao theoretically determined a maximum achievable efficiency of 25 per cent.

In 1983, at UNSW, Professor Green and Professor Blakers produced solar cells with 18 per cent efficiency, surpassing the previous record of 16.5 per cent.

In ensuing years, they published cell results of 19 per cent and 20 per cent efficiency.

Before the invention of PERC, most solar cells’ efficiency was limited by photon-generated electrons being lost through recombining with the thick, doped silicon layer at the back surface. To overcome this, PERC introduced an additional layer on the back surface that helped prevent recombination by reflecting unused photons back into the silicon to generate more electrons.

The team published their first paper on PERC technology in 1989, spruiking 22.8 per cent efficiency.

Professor Green’s lab at UNSW held the global record for efficiency for 30 of 40 years from 1983 to 2023, with Dr Wang and Dr Zhao leading the work which eventually reached Green’s 25 per cent efficiency target.

They opted to publish rather than patent, since commercial uptake seemed remote, freeing PERC technology to be widely adopted.

It took two decades of development before PERC technology entered the mainstream, however it is now the most commercially viable silicon solar cell technology for use in solar panels, accounting for almost 90 per cent of the global solar cell market.

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