February 19, 2009
Cheaper Starting Materials For Cheaper Solar Cells

Some Berkeley researchers believe that starting with cheaper raw materials is the road to much cheaper photovoltaics.

Berkeley -- Unconventional solar cell materials that are as abundant but much less costly than silicon and other semiconductors in use today could substantially reduce the cost of solar photovoltaics, according to a new study from the Energy and Resources Group and the Department of Chemistry at the University of California, Berkeley, and the Lawrence Berkeley National Laboratory (LBNL).

These materials, some of which are highly abundant, could expand the potential for solar cells to become a globally significant source of low-carbon energy, the study authors said.

The analysis, which appeared online Feb. 13 in Environmental Science & Technology, examines the two most pressing challenges to large-scale deployment of solar photovoltaics as the world moves toward a carbon neutral future: cost per kilowatt hour and total resource abundance. The UC Berkeley study evaluated 23 promising semiconducting materials and discovered that 12 are abundant enough to meet or exceed annual worldwide energy demand. Of those 12, nine have a significant raw material cost reduction over traditional crystalline silicon, the most widely used photovoltaic material in mass production today.

Silicon crystals and some of the elements in photovoltaic thin films (e.g. the indium and gallium in CIGS - copper indium gallium selenide) are expensive and in limited supply. So how can they scale? By contrast, iron is a lot more plentiful and cheaper/

The team identified a large material extraction cost (cents/watt) gap between leading thin film materials and a number of unconventional solar cell candidates, including iron pyrite, copper sulfide and copper oxide. They showed that iron pyrite is several orders of magnitude better than any alternative on important metrics of both cost and abundance. In the report, the team referenced some recent advances in nanoscale science to argue that the modest efficiency losses of unconventional solar cell materials would be offset by the potential for scaling up while saving significantly on materials costs.

Will materials manipulated on the nanoscale be craftable into higher efficiency photovoltaics?

Share |      Randall Parker, 2009 February 19 12:20 AM  Energy Solar

Engineer-Poet said at February 19, 2009 4:44 PM:

What's so expensive about silicon?  Can't SRI's process turn it out for a few bucks a kg?  The expensive part is making big single crystals, and that's just not all that important.

malcolm said at February 19, 2009 9:01 PM:

Are we really supposed to believe "mining" silicon is difficult? Is sand not usable for some reason?

Nick G said at February 19, 2009 9:03 PM:


Besides, the cost of the PV itself is starting to become less important than the Balance of System (panel, mounting, wiring, inverter, controls). That may be the place where creativity is needed most.

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