The 2022 Millennium Technology Prize has been awarded to Scientia Professor Martin Green of the UNSW Sydney, Australia, for his innovation that has transformed the production of solar energy.
The €1 million global award for technology, conferred every two years, recognized Green’s leadership in the development of the Passivated Emitter and Rear Cell (PERC). Since its development in 1983, the PERC has gone on to become the most commercially viable and efficient silicon solar cell technology for use in solar panels and for large-scale electricity production, accounting for almost 90% of the global solar cell market.
Green developed the PERC with his team by improving the quality of both the top and the rear surface of standard silicon solar cells. When sunlight – in the form of particles called photons – enters a cell, it excites the electrons within the silicon. In this excited state, electrons can move through the cell, creating electric current.
The improved surface of the PERC allows the electrons to maintain this excited state – or move freely – for longer, resulting in greater and more efficient energy generation. The PERC has 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 innovation has greatly reduced the costs of using solar panels, making solar energy more affordable than fossil-based alternatives. PERCs can also provide an energy supply to homes without them needing to be connected to a grid, ensuring a reliable power supply for remote communities.
Professor Green said, “It is a great honor to have been selected to receive such a prestigious prize. It not only recognizes my contribution to photovoltaics [the conversion of light into electrical power], but also the achievements of my students and research colleagues at UNSW, as well as those of the broader photovoltaic research and commercial community.
“I believe the Prize will increase my credibility as a spokesperson for what needs to be done to address climate change. We need to switch from fossil fuels to renewable energy to sustain the trajectory of human civilization on our shared planet. The pace of change is accelerating and the world will shift to solar and wind energy over the coming decade. I believe a huge transformation of historic significance is underway.”
Green and his team are currently working on combined cell technologies to reach 40% solar cell efficiency by exploring options such as stacking cells on top of one another.
Green said, “Solar cells are increasingly being used to replace large power stations that use fossil fuels. In 2021, 20 countries or regions including Australia, Chile, Germany, Greece, Italy, Netherlands, Spain, Vietnam and California (US) generated between 8% to 25% of their total electricity supply from solar energy, with this number growing quickly.
“The rapid cost reductions in solar energy that my work has facilitated have come just in time, right at the point when the importance of acting immediately to address climate change has become overwhelmingly obvious.”