Major switch for solar energy: Researchers
investigate use of carbon-based materials to produce
Nov 27, 2007 - Larry Rulison - Albany Times Union
- McClatchy-Tribune Regional News
In a small physics lab on the uptown campus of the
University at Albany, researchers are trying to develop
a new type of solar-electric cell that will be cheaper
-- and more flexible -- than a traditional solar cell
made from silicon.
About 90 percent of solar cells are made from silicon.
But there's a mad dash to make the cells from organic
material to reduce the cost and foster wider acceptance
of the technology.
The organic solar cells are made of alternatives
to silicon such as polymers or plastics.
Solar, or photovoltaic, cells produce an electric
current when exposed to light.
Organic materials are those derived from carbon,
which is the building block of life. Silicon, made
from sand, is the same semiconducting material that
is used to make computer chips.
Silicon solar cells cost from $3 to $3.50 for each
watt of electrical output they produce. Achieving
the same electrical output costs just 40 cents using
"That's why there is the interest in organics," said
Pradeep Haldar, a professor at UAlbany's College of
Nanoscale Science and Engineering and director of
the school's Energy and Environmental Technology Applications
Haldar said his work on organic solar cells is being
funded by NASA, which is seeking ways to make flexible
solar cells that can be unfolded in space.
He believes organic solar cells won't replace silicon
solar cells, but as the technology is perfected, the
former will serve in niche applications such as powering
computers for the military in the field or for putting
solar cells on clothing or tents.
Haldar isn't the only one in the Capital Region searching
for a better way to make solar cells. DayStar Technologies
Inc. in Halfmoon is working to develop so-called "thin-film"
cells made from a mixture of copper, indium, gallium
and diselenide that are flexible like organic cells,
but more expensive. It takes $2 worth of material
to produce each watt of electrical output.
The downside of organic solar cells is their relative
inefficiency. Polymer-based solar cells have an efficiency
of less than 5 percent, while solar cells using single-crystalline
silicon have an efficiency of nearly 25 percent. That
means the polymer cells must cover an area five times
the size of solar cells to produce the same amount
Organic solar cells also don't last as long as traditional
"If you expose it to air, it degrades," Haldar said.
"That's one of the biggest problems."
Haldar and his team of scientists are working to
improve the longevity of organic solar cells by adding
copper nanorods to the devices.
Another upstate New York researcher working on organic
solar cells is George Malliaras, an associate professor
in materials science and engineering at Cornell University
in Ithaca who also is director of the school's nanoscale
Malliaras says organic solar cells can be a lot
cheaper than silicon solar cells because of the way
they can be manufactured, in a roll-to-roll process
similar to how a newspaper press works.
"That can bring down the cost substantially," Malliaras
said Monday. "If you can produce electronics the same
way you produce a newspaper, the costs will plummet."
Malliaras also is working on a new process that makes
organic solar cells using a spray-on technique for
applying the components of the cell. Larry Rulison
can be reached at 454-5504 or by e-mail at firstname.lastname@example.org.