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2004 World Technology Awards Winners & Finalists

Martin Green

Please describe the work that you are doing that you consider to be the most innovative and of the greatest likely long-term significance.

My most innovative work of potentially greatest long-term significance involves improving the efficiency and economics of converting sunlight to electricity using solar cells. Technically, these could supply all the world’s primary energy (only 1% of the land area required) and are well-suited for both developed and developing world application, but high costs have hampered widespread use. Several governments (notably Japanese and German) have recognised this potential, implementing schemes to accelerate adoption. Production has grown 30-40%/annum over the last seven years, with wind, the fastest-growing electricity generation option.

I became interested in microelectronics at high school in Australia, tailoring studies accordingly. As I matured, I became increasingly disillusioned with this choice. A travelling-scholarship after third-year University introduced me to solar cells while visiting a Sydney microelectronics company. I steered subsequent doctoral studies in Canada towards photovoltaics. On return to Australia in 1974, I started a photovoltaic group at the University of New South Wales in Sydney, now recognised as one of the most prolific and successful internationally.

During the contemperaneous oil embargoes, a large USA solar program was launched at still-unequalled funding levels. Competing with this program, but on a very modest budget, using equipment rescued from the scrap heap, my small team started making progress. In 1983, we set our first world-record for silicon cell efficiency. In 1985, we achieved the photovoltaic “four minute mile”, the first 20% efficient silicon cell (20% of the incident sunlight energy converted to electricity). Our group has held the world-record for silicon efficiency ever since (excepting six months in 1988), improving efficiency by over 50% (relative) to 24.7%.

In parallel, we sought simplifications to get these improvements into commercial production. Myself and PhD student, Stuart Wenham, invented a low-cost, high-efficiency “buried-contact” cell, one of the most successfully commercialised developments since then. Sales under license currently exceed US$300 million, certain to exceed US$1 billion by 2010.

With those particular oil crises waning, so did research funding. Suddenly, we were one of few strong groups remaining, with self-imposed responsibility to tackle the field’s most important problems. I believed this was the development of inexpensive “thin-film” technology, eliminating the near microelectronics-grade silicon wafers underpinning present technology.

Although other thin-film technologies had been developed, these were judged unsuitable (instability of reasonable efficiency devices [amorphous-silicon], toxicity [cadmium-telluride] or insufficient resources [copper-indium-diselenide]). Emboldened by past successes and the importance of the outcome, we braced ourselves to develop, from scratch, a thin-film approach based on abundant and benign silicon, the same as in the successful, if expensive, wafer approach. For several reasons, this is technically challenging, with one expert in the 1970s famously rating silicon thin-film cell prospects as “million-to-one”.

With the recent announcement of a European consortium, headed by Europe’s largest conventional cell manufacturer, formed to commercialise our resulting “silicon-on-glass” technology during 2005/2006, photovoltaics may finally attain its full potential as a sustainable source of cheap electricity for both the developed and developing world.

My work, therefore, has involved greatly improving silicon cell performance, increasing the field’s expectation of what is possible, plus the development of successful commercial technology for both first-generation wafer-based technology and second-generation thin-films.

I have also catalysed commercial and educational developments, with former students establishing manufacturing plants in Australia (the basis for BP Solar’s 1985 manufacturing entry, now a top-3 manufacturer), more recently in China (Suntech now a top-10 manufacturer, presently the world’s fastest growing), and now in Europe. Many researchers entering the field have learnt about photovoltaics from my textbook “Solar Cells”. I also helped establish the world’s first undergraduate photovoltaic programs, with heavy involvement in developing world applications.

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Brief Biography

Martin Green was born in Brisbane, Australia in 1948. Educated at Brisbane State High School, he received the Lilley Medal for topping Queensland’s 1965 Senior Matriculation Examination. After graduating from Queensland University, he completed doctoral studies at McMaster University, Canada. Recently, both Alma Mater separately honoured him as Alumnus of the Year (Queensland, 2000; McMaster, 2002).

He joined the University of New South Wales in 1974, initiating the Solar Photovoltaics Group. From the late 1970s, this group headed international efforts to improve silicon solar cells, producing 18% efficient cells in 1983, significantly higher than previously. In 1985, it achieved photovoltaic’s “four-minute-mile”, the first 20% efficient silicon cell. His group has since held the world-record for silicon cell efficiency continuously (apart from six months in 1988). His group’s present 24.7% record represents over 50% improvement relative to the best before this work, despite 30 years prior development.

This work was recognised by the 1982 Pawsey Medal (Australian Academy) for “distinguished research in experimental physics”, the 1988 Award for Outstanding Achievement in Energy Research (Australian Industry Confederation), the IEEE Cherry Award in 1990 for “outstanding contributions to photovoltaic science and technology”, the major international award for photovoltaic research, and the 1995 IEEE Ebers Award for “sustained technical leadership in the field of silicon photovoltaic solar energy conversion”, the highest international recognition for electron device research, awarded previously exclusively for work in the USA, Europe or Japan.

Work with former student and close colleague, Stuart Wenham, on commercialising these improvements via the “buried-contact” cell, has been recognised by joint award of the 1992 CSIRO External Medal and 1999 Australia Prize (highest Australian Government scientific award). Martin Green also received the Gold Medal from the Spanish Engineering Academy (2000) for photovoltaics work, particularly that boosting Spanish industry.

His early teaching led to the textbook “Solar Cells: Operating Principles, …......” (Prentice-Hall, 1982), probably the field’s most widely-used, introducing many current researchers to photovoltaics. He has since published several other books ranging from popular science, “Power to the People” (UNSW Press, 2000), to specialised research monographs, “Third Generation Photovoltaics: Advanced Solar Conversion” (Springer, 2003). Many of 30-plus doctoral students have subsequently independently contributed to photovoltaics, in academia or industry. In 1999, his group started the world’s first undergraduate photovoltaics program, anticipating present international demand for suitably-qualified engineers.

Breadth of activities is suggested by awards including Aviation Week’s for developing 20% efficient space cells for NASA and Motor’s “50 Most Interesting People in the Automobile Industry” for photovoltaics promotion through solar car racing (cells on three winners of first five triennial international races). Fellow engineers voted him as one of Australia’s “top ten engineers of the 20th century”.

Elected to Fellowship of the IEEE (1988) and both the Australian Academy of Science (1990) and of Technological Sciences and Engineering (1994), he received the inaugural Medal of Engineering Excellence for Distinguished Achievement in the Service of Humanity from the World Engineering Federation (Hannover, 2000), the 2000-Millennium Award from the World Renewable Congress for “the outstanding scientist in his/her field”, and the 2002 Right Livelihood Award (the “Alternative Nobel Prize”) in the Swedish Parliament for “dedication and outstanding success in responding to the key technological and moral imperative of our age: the harnessing of solar energy”.

Martin Green is presently an Australian Federation Fellow, holding a Scientia Professorship at his University, as Research Director of the Centre for Advanced Silicon Photovoltaics and Photonics. He is also Research Director of CSG Solar, a company formed to commercialise next-generation “crystalline silicon on glass” thin-film solar cells he helped develop. He lives in Sydney near Bronte Beach with his wife, Judy.

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