My colleague Mark Keevers and I led a team that has set a new world record in converting sunlight into electricity. We achieved an efficiency of 40% by splitting a single beam of sunlight across two different types of solar cells. The innovative part of our work is the use
of a custom designed bandpass filter that optimally splits the sunlight so that the best range of wavelengths falls on the cell specialised for that conversion. Our prototype concentrates the sunlight to about 365 suns and to keep it real we use commercial silicon and gallium arsenide concentrated solar cells. The 40% result demonstrates proof-of-concept of this relatively simple spectrum-splitting
approach. The results of our work are particularly
relevant to the photovoltaic power towers being developed here in Australia.