Green, M. A.Blakers, A. W.Wenham, S. R.Narayanan, S.Willison, M. R.Taouk, M.Szpitalak, T.2026-01-042026-01-040160-8371ORCID:/0000-0002-0800-2276/work/162946144https://hdl.handle.net/1885/733803563Four significant results are described relating to improved solar cell efficiency. These are: (i) the demonstration of cells with efficiencies in excess of 20% under terrestrial test conditions (AM 1. 5, 100 mW/cm**2 , 28 degree C); (ii) the demonstration of cells with greater than 18% efficiency under space radiation (AM0, 25 degree C); (iii) the development of a very practical sequence not requiring photolithography, vacuum evaporations, or double layer antireflection coatings which produces similarly high efficiencies; and (iv) the demonstration of 18% efficiency with this approach using solar-grade Czochralski substrates of both small and large area.We acknowledge the contributions to this work of other members of the Solar Photovoltaic Laboratory, particularly E. M. Keller, T. Szpitalak, S. R. Wenham and M. R. WiUison. We would also like to thank C. Osterwald, B. Rose and their colleagues at SERI and Sandia respectively for detailed cell characterization. We acknowledge the assistance of N. Arberger and O. Holl-richer of Wacker-Chemitronic in securing sample quantities of high quality float zone silicon. One of us (A.W.B.) acknowledges the support of a Radio Research Board Postdoctoral Fellowship. We also acknowledge the past support of this work by the Australian National Energy Research, Development and Demonstration Council. The Solar Photovoltaic Laboratory forms part of the Joint Microelectronics Research Centre which is supported by the Commonwealth Program for the Promotion of Excellence in Research.4en19850022329769