By Gary Thomas
Scientists state that less-expensive solar energy technology is required to install shingled roofs in homes which produce electricity. Advances towards such technology are being reported.
Using common materials available abundantly on the planet can increase the affordability of photovoltaics and also enable their integration in other parts of buildings. The rare-earth elements – gallium and indium are presently being used, but they are a scarce commodity. Over 90% of these elements are mined by China for use in electronics, magnets, hybrid cars and other products. The new technology suggests the use of copper, zinc and other such materials that are comparatively less-expensive and more abundant.
This research was presented at the 244th National Meeting & Exposition of the American Chemical Society as part of a symposium on sustainability. Harry A. Atwater, a California Institute of Technology physicist and James C. Stevens, a Dow Chemical chemist, discussed the efforts undertaken towards replacing costly and rare earth metals with more sustainable, cost-effective materials for photovoltaic devices.
They described new devices that were manufactured using copper oxide and zinc phosphide. These devices demonstrated better voltage and current than zinc and copper thin-film solar energy conversion devices. Within a period of 20 years, materials such as copper oxide and zinc phosphide will be developed to show very high efficiencies and will be able to produce electricity at a cost similar to that of coal-fired power plants.
Dow had launched a solar shingle in October 2011. Copper indium gallium diselenide photovoltaic technology is used in these shingles for generating electricity. Researchers are considering the use of sustainable earth-abundant materials in Dow’s solar shingles.
Around 50% of the electricity required for the U.S. can be acquired by harvesting the energy of sunlight falling on roof tops.