A study from the Energy and Resources Group and the Department of Chemistry at the University of California, Berkeley, and the Lawrence Berkeley National Laboratory (Berkeley, CA) describes several alternatives to silicon that could dramatically increase large-scale deployment of solar photovoltaics.
Although less costly than silicon and easier to produce, thin-film technologies would rapidly deplete natural resources if scaled to the terawatt-levels of annual manufacturing production required, due to their low conversion efficiencies. Interested in finding alternatives, the Berkeley study looked at 23 semiconducting materials and found nine that are significantly lower in cost than crystalline silicon, including iron pyrite, copper sulfide, and copper oxide. Iron pyrite (FeS2) was found to be several orders of magnitude better than any alternative when considering cost and abundance. Despite a power-conversion efficiency of only 4% (compared to around 19% for crystalline silicon), iron pyrite’s ultralow material cost—$0.03/kg versus $1.70/kg for silicon—would more than offset efficiency losses in a large-scale solar-cell production scenario. Contact Daniel Kammen at [email protected] or http://rael.berkeley.edu.