UNSW Sydney solar pioneers celebrate 50 years of world-leading research and innovation

Humble beginnings

Prof. Green described how his first lab was set up in a meeting room off the professorial office of his departmental head, Lou Davies.

“Lou gave me some space and helped to rescue some technical equipment from the rubbish heap for my fledgling group.

“We had a crack team of young researchers, among them my first three PhD students, Bruce Godfrey, Andrew Blakers and Stuart Wenham, who were driven, inspired and passionate about the possibilities of pushing the technology to new levels,” he said.

Prof. Green and his colleagues developed their first working ‘TOPCon’ solar cell by 1981, becoming the first to demonstrate the viability of this technology. In 1983 they beat the rest of the world – including NASA and Stanford University, which were also racing to develop the technology – producing the most efficient silicon solar cell globally. This established UNSW’s reputation on the world stage, attracting international grants funding and the opportunity to accelerate their research. 

The birth of the modern solar cell

The team knew that if they were ever going to realise the dream of producing the cells commercially, they’d need to push the efficiency – the ratio of energy that falls on solar panels as sunlight to the electricity produced as a result – to the limit to cut manufacturing costs as much as possible.

Prof. Green devised a cell that was simpler to fabricate than the earlier models. He led the team that invented the Passivated Emitter and Rear Cell (PERC) in 1983, a project that changed the course of history.

PERC helped increase the conversion efficiency of standard solar cells by over 50% in relative terms from 16.5% in the early 1980s to 25% in the early 2000s.

“The team was reinforced by my first four Chinese-born PhD students in the late 1980s and early 1990s – Jianhua Zhao, Zhengrong Shi, Aihua Wang and Ximing Dai – who became Australian citizens. They, along with our equipment guru, Ted Szpitalak, played a crucial role not only in our cell development, but in the solar cost reductions of the last decade. This was done by founding and attracting US investment into three of the first companies manufacturing in China via Australian-Chinese joint ventures.”

The world’s first solar undergraduate degree

It wasn’t just silicon solar cells that were first developed at UNSW. Building on their research strengths and thanks to their visionary leadership, the late Professor Stuart Wenham and Prof. Green established the world's first undergraduate teaching programme in photovoltaics (solar) and renewable energy engineering in 2000. It’s been 20 years since the first students graduated. The University’s 2000-plus solar alumni are among the most sought-after talent in the sector worldwide.

The Head of the School of Photovoltaic and Renewable Energy Engineering (SPREE), Professor Alistair Sproul, said he was incredibly proud of the significant role UNSW academics and graduates have had in the renewable energy transition.

“SPREE’s success in conceiving and developing world-leading technology such as PERC and TOPcon means UNSW technology is now at the heart of about 90% of all solar modules produced today,” he said.

“Prof. Green has consistently had an enormous impact over the past 50 years, always at the forefront of photovoltaic research as well as successfully transferring many technologies to industry. And his success has attracted incredibly talented and like-minded people to accelerate research in photovoltaics and sustainable energy even further.”

Celebrating 50 years of solar technology research and 20 years since the first graduates

Prof. Green joined some of SPREE’s former students – now in senior industry roles – on a panel at the weekend, at an event to mark the two milestone anniversaries – and to talk about what the future holds for solar energy.

Dr Oliver Hartley argued Australia has a phenomenal opportunity to become a major green energy exporter by harnessing the country’s renewable resources, along with our homegrown expertise.

Chris Davies believes Australia has the potential to lead in integrating renewables and operating large grids. He said it’s possible for the East Coast grid to be operating at 100% renewables within 10 years.

Dr Nicole Kuepper-Russell is excited about producing super-cheap solar technology at large scale, and believes we have legitimate technology pathways to get there.

Dr Rong Deng says we have the capacity to recycle old panels to create new ones, and that by 2045, all solar panels could be manufactured from old ones.

Prof. Green said photovoltaics is already the cheapest electricity in history, and he’s working on ways to make it even cheaper in the future.

Chasing the dream – new solar technology research

Fifty years on from when he started, Prof. Green is still in the trenches of solar energy research, with no signs of slowing down.

He said: “PERC kickstarted the solar boom. But there is still enormous scope for improvement, such as through tandem cell stacks with the potential to drastically increase the energy output.

“Silicon cells are very good at converting red photons from sunlight, but not so efficient at converting blue ones, since they waste a lot of their energy. So we’re working on stacking cells on top of each other, which would work in tandem to convert different parts of the solar spectrum into electricity. We believe this innovation could boost commercial cell efficiency to over 40% in future,” Prof. Green said.

The future is green. Tell that one the next time you’re asked to name a legendary Aussie invention.