ENGINEERING

Solar for Less

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Science  27 Feb 2009:
Vol. 323, Issue 5918, pp. 1149
DOI: 10.1126/science.323.5918.1149c

The Sun provides far more energy to Earth each day than the worldwide population currently uses, but directing this energy toward a more useful purpose than heating the ground is a considerable challenge. Though siliconbased cells can effectively convert absorbed light into electricity, the costs associated with isolating and purifying the silicon toward this end remain substantially higher than those associated with fossil fuel-based processes for electricity generation. Wadia et al. have analyzed the relative costs and efficiencies of a wide range of alternative materials for eventual use in solar cells. Specifically, they examined 21 metal oxides, sulfides, selenides, and sundry other inorganic semiconductors in comparison with crystalline and amorphous silicon. Their model considered overall electricity consumption, and so evaluated power-conversion efficiencies of individual cells in the context of comparative fabrication costs for multiple cells. Iron pyrite emerged as an especially favorable option on the basis of its abundance and low extraction cost, with Zn3P2 and copper oxides also showing potential for economical efficiency. — JSY

Environ. Sci. Technol. 43, 10.1021/es8019534 (2009).

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