Silicon Photovoltaic Solar Cells

Silicon Photovoltaic Solar Cells
Martin Green and Stuart Wenham
Scientia Professors Stuart Wenham and Martin Green
Scientia Professors Stuart Wenham and Martin Green on the roof of the UNSW Tyree Energy Technologies Building.
UNSW engineers hold the world record for conversion efficiency for silicon solar cells. The impact of their pioneering research extends globally across the entire solar power industry.

Around the world, billions of solar photovoltaic (PV) panels are powering homes, buildings, infrastructure and remote communities by converting sunlight directly into usable electricity.

Solar is an important part of the renewable energy mix that will help move our global economy away from its reliance on fossil fuels, and the PV industry has benefited greatly from the pioneering work of UNSW researchers.

In 1974, a young Australian named Martin Green began working at UNSW after completing his doctorate on the structure of innovative microelectronics.

A year later, Green’s research team produced its first silicon solar cell. It was the first step on a four-decade-long journey that has cemented UNSW’s reputation as a world-leading solar photovoltaic research institution.

When Green came to UNSW, photovoltaic technology was still in its relative infancy. While the first solar photovoltaic cell was developed in 1941, it had less than 1% energy conversion efficiency.

In the 1960s, after rapid efficiency progress, the technology began to find applications providing power onboard spacecraft. And after the energy crises in the 1970s, it gained momentum as a possible supplementary power source.

Although NASA was the early international leader in photovoltaic science, the small research team at UNSW was making giant strides thanks to Green and a team of remarkable young scientists and engineers that later included Dr Stuart Wenham.

Green was focused on making silicon cells as efficient and affordable as possible, and by 1983, UNSW’s high-performance silicon solar cells had surpassed the best cells made anywhere in the world. Their group was attracting international attention and had secured NASA funding. 

In 1985, the team hit the 20% milestone with its buried contact solar cell. It was a record-setting achievement that ushered in the modern period of solar cell development.

Their buried contact technology became a huge commercial success and was licensed to some of the world’s largest solar cell manufacturers, including Samsung in Korea and energy giant British Petroleum. More than US$1 billion of products are now deployed.

“We were producing a lot of cells that were being used for solar car racing,” says Scientia Professor Green. “This provided an opportunity to really fine-tune the processing and get far ahead of the other research labs around the world.”

It’s an advantage UNSW researchers have maintained. In 1994, Green and Wenham developed and commercialised a prototype thin-film solar cell. And in 2008, they set the current world record for conversion efficiency at 25% with their PERL cells – variants of which, known as Pluto, have been commercialised by Suntech Power.

The research group currently has multiple projects underway looking at pushing efficiencies to greater than 40% by stacking cells from other semiconductor materials on top of silicon. 

“Our international reputation means we can assemble teams of people around the world to work on projects that would be too challenging for any one team – and we can have multiple approaches going in parallel. This is a major advantage,” says Green, who was inducted into the Fellowship of the Royal Society in 2013 for his contributions to the field of solar energy. 

Quote: 
“By his election to the Royal Society of London, Martin Green’s achievements in the research and development of silicon-based solar cell technology is recognised as being of world-leading quality and world-changing significance.”
Author: 
Michael Kelly, Prince Philip Professor of Technology at the University of Cambridge and Royal Society Fellow
Quote: 
“Our international reputation means we can assemble teams of people around the world to work on projects that would be too challenging for any one team – and we can have multiple approaches going in parallel. This is a major advantage.”
Author: 
Scientia Professor Martin Green, School of Photovoltaic and Renewable Energy Engineering
Timeline
Timeline: 
Year: 
1975
Event: 
First silicon solar cell produced at UNSW
Year: 
1981
Event: 
UNSW researchers establish Australia’s first solar cell production line
Year: 
1984
Event: 
Buried contact solar cell developed
Year: 
1985
Event: 
World’s first 20% efficient silicon solar cell developed
Year: 
1989
Event: 
First 20% efficient space cell verified on NASA’s high-altitude craft
Year: 
1990
Event: 
23% efficient cell developed at UNSW sets new world record
Year: 
1993
Event: 
World’s first 20% efficient module based on the buried contact solar cell
Year: 
1994
Event: 
24% efficient cell sets new world record
Year: 
1998
Event: 
Laser Doping Selective Emitter process established and patented
Year: 
1999
Event: 
Martin Green and Stuart Wenham win the Australia Prize
Year: 
2000
Event: 
ARC Centre for Third Generation Photovoltaics established
Year: 
2003
Event: 
ARC Photovoltaics Centre of Excellence established
Year: 
2007
Event: 
Buried contact sales under licence to UNSW exceed US$1 billion
Year: 
2008
Event: 
25% efficiency achieved with PERL cells; Suntech Power begins large-scale production of commercial variant Pluto
Year: 
2010
Event: 
UNSW sets the module efficiency record at 16.5%
Year: 
2011
Event: 
Approximately US$1 billion of Pluto cells produced annually
Year: 
2013
Event: 
Martin Green elected to the Fellowship of the Royal Society