High-efficiency solar cells based on gallium arsenide (GaAs) and related "III-V" materials have historically been used in space applications. Our current goals are to take this technology a step further by developing it as a concentrator technology and expanding it to include triple-junction devices. We are also investigating devices using low-cost substrates (such as glass). Our long-term objective is to establish III-V materials as a competitive terrestrial PV technology by developing the materials science, advancing related science and engineering, coordinating relationships with our industry and university partners, and facilitating commercialization.
Developing multijunction technology. Although the gallium indium phosphide (GaInP)/GaAs tandem cell has achieved an efficiency of 30% and is now commercially available for space applications, the cells have not yet been integrated into a concentrator system. This is primarily because concentrators have been considered a future-generation PV technology. However, the highest-efficiency and lowest-cost new module on today's market is a concentrator system, which shows that this technology's time has come. So, we are working with the cell manufacturers and concentrator companies to foster the adaptation of this technology in the U.S. utility market, as well as designing and developing a novel, three-junction concept with an ultimate goal of 35% efficiency.
Developing materials and high-efficiency (>20%) devices on low-cost substrates. Developing III-V devices on low-cost substrates for flat-plate applications is a high-risk, high-payback approach that could yield a new, future-generation technology. Already, large-grain, oriented crystalline layers have been grown on amorphous substrates to produce superconductors and other materials, but these techniques have not been fully investigated for III-V materials. Preliminary work at the California Institute of Technology has shown that the crystal size can potentially be increased to tens or hundreds of micrometers (possibly even larger) if the technique is pushed to its limit. We believe that we can combine these and a number of other growth techniques to grow thin, III-V layers on glass, and with large grain sizes and uniform orientation. We believe this will allow us to duplicate the structures that currently produce efficiencies as high as 30%. We are coordinating this work with the New Ideas work on low-cost substrates for high-efficiency cells.
We are also working to build on our existing relationships with industry and university partners. In 1997, we will conduct a workshop on low-cost III-V materials and devices to identify enabling technologies and industry and university partners capable of accelerating progress. We will continue by coordinating the related research and development of these new partners.
Solar Systems Pty Ltd, Hawthorn, Victoria, have announced an agreement with Boeing Australia Ltd for supply of Spectrolab solar cells. The agreement will result in the supply of 500,000 cells, capable of generating 11MW of electricity.

Spectrolab produces multi-junction solar cells, originally designed for powering satellites. The solar cells are three times more efficient than the cells used in typical domestic solar panels, and are capable of converting light energy to electrical energy with up to 34% efficiency according to NREL's National Centre for Photovoltaics. Solar Systems utilise Spectrolab's multi-junction solar cells to increase the output of their dish systems.

Solar Systems have already trialed the cells in one of their CS500 concentrating solar dishes installed at a solar power station in Hermannsburg, Central Australia, established to reduce the consumption of diesel in the remote community. Simply replacing the existing cells with the Spectrolab multi-junction solar cells increased output from 24kW to 34kW.

Solar Systems is planning to use the technology in a solar power station it will build in northern Victoria, with a capacity of 154MW.