In 1990, the U.S. space probe Voyager I captured a series of photographs of the sun on a voyage to the edge of the Solar System. Today, scientists are working to develop new materials and strategies for designing photovoltaic systems that convert sunlight into electricity.
Showering Earth with an energy flow of some 120,000 TW, the sun would appear to be a limitless non-carbon-emitting energy fountain capable of meeting worldwide energy demands. “There’s no doubt that we have ample energy resource in the sun,” Lewis stresses. The challenge, he says, is figuring out how to tap into it inexpensively.
That challenge has been driving researchers to develop new materials and strategies for designing photovoltaic systems that convert sunlight into electricity. In addition to exploring new methods for reducing the cost of solar cells based on silicon, the traditional photovoltaic material, scientists have been experimenting with other semiconductors, inorganic nanocrystals, organic polymers, and a host of other light-sensitive materials.
For decades, high-purity crystalline silicon solar cells have provided electrical power for a number of high-end applications such as space vehicles. Although such cells’ performance and longevity testify to the technology’s reliability, the high costs of the crystal-growth and manufacturing processes used for fabricating top-of-the-line photovoltaic modules (multicell units) make those types of devices too expensive for widescale use. To reduce costs, some manufacturers have turned to less expensive forms of silicon including polycrystalline, nanocrystalline, and amorphous silicon. In addition, they’ve developed cost-saving strategies that reduce the quantity of silicon used per cell.
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Excerpted with permission, Chemical & Engineering News
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