Scientia Professor Martin Green of the UNSW Sydney, Australia, received the Millennium Technology Prize 2022 for his innovation that has transformed the production of solar energy.
The award recognises Green’s leadership in the developmentof 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.
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 each other.
