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Martin Andrew Green and Stuart Ross Wenham (University of New South Wales, Sydney, Australia)
Non-European countries:
Martin Andrew Green and Stuart Ross Wenham (University of New South Wales, Sydney, Australia) succeeded in converting solar energy directly into electrical power. Based on silicon technology, their solar cells are particularly efficient and also far more cost-effective than their predecessors. They powered the Olympic Village at the Sydney 2000 Games, and in Europe photovoltaic cells based on the Green principle are now the most frequently produced type. Professor Martin Green has already been awarded the Alternative Nobel Prize in Stockholm.
Seeing the Light
The inventors developed solar cells with the highest efficiency ever
achieved. They also invented a method for increasing the concentration
of light sent to solar cells.
The innovation of Buried Contact Solar Cell by Australians Martin Green
and Stuart Wenham may play an important role as the world develops alternative
energy sources. Discovered at the University of New South Wales (EP156366,
patent published on March 25, 1992), the inventors formed Unisearch (later
renamed NewSouth Innovations) to exploit the discovery’s commercial
potential.
The key innovation in this patent is that a series of contacts is formed
not directly on the front surface of the solar cells – as had been
done previously – but in a groove, going deep into the substrate
of the cell. Green and Stuart found this greatly increased the contact
surface compared to a non-buried contact. More light was trapped using
this method, creating an increase in the energy conversion efficiency
of the solar cell.
The second patent by Green and Wenham is Optical Design For Photo-Cell
(EP607251, patent published on December 27, 2000) which is concerned with
the concentration of light sent to solar cells.
The inventors created a light guide for solar cells that traps the incoming
light and does not allow it to leave the device. As light enters from
outside, it is internally reflected many times on the surfaces of the
device, irrespective of the angle at which the light enters. This process
increases energy production from the solar cells.
The two innovations have very different stories when it comes to commercial
applications.
Optical Design For Photo-Cell reached the stage of advanced prototypes
but has not yet been used commercially. The first problem was that the
invention required solar cells that responded to light falling on both
sides, and such cells were not being produced in volume at the time. The
second issue was money: No cost-effective method of producing the optical
elements had been devised.
The same cannot be said for Buried Contact Solar Cell, which was famously
used in the 1990 World Solar Challenge, a solar car race across Australia.
The winning car was powered by cells created using Green and Wenham’s
patent.
The profile of the patent continued to grow when in 1994 BP Solar used
the cells in what was then Europe's largest solar system, in Toledo, Spain.
“The skills and technology extensions we have developed around the
processes used for the buried contact solar cell provide a solid foundation
for our future generation technologies,” said a spokesperson for
BP Solar. “The buried contact cell technology enabled us to develop
a leading high efficiency cell process.”
For their work in photovoltaics/solar cells Martin Green and Stuart Wenham
won the 1999 Australia Prize – the country’s most prestigious
science award.
Both inventors are still closely linked to the University of New South
Wales, with Green acting as director of the university’s photovoltaics
special research centre, and Wenham director of the centre of excellence
for advanced photovoltaics.
Wenham spent nine years as the co-director of Research at Pacific Solar
Pty where Green – author of four books on solar cells – is
currently a research director.
It may be decades before the world has to be powered by solar, but if
that time comes, two men from Australia may become household names.