Science has spent the past several decades attempting to
increase the efficiency of solar cells in order to make solar energy a viable
alternative to fossil fuels. The
average solar cell has a 15-20% efficiency (i.e. converting 15-20% of solar
energy into usable electricity).
Sharp Electronics has managed to develop a solar cell boasting 44.4%
efficiency, however this is a concentrator system which requires lenses to
concentrate sunlight onto the solar cells. But the scientists at MIT are working on a solution that
actually reduces the efficiency.
Huh?
Jeffrey Grossman, senior author of a new paper published in Nano Letters, is using nanotechnology in
an effort to improve the functionality of solar cells. Using graphene (a one-atom thick sheet
of carbon atoms) and molybdenum disulfide (a one atom thick sheet of molybdenum
and sulfur) together to form a 2 atom thick sheet produces a solar cell capable
of converting sunlight to electricity at an efficiency of 1-2%. While hardly efficient, because it is
only 1 nanometer thick (1 billionth of a meter), they can be stacked to boost
the overall efficiency of the system.
Pound for pound, this new material generates a 1,000 times more energy
than conventional photovoltaics.
This can open the door for weight-sensitive applications such as
aircraft or hard to access locations where transportation costs factor in.
While it is not yet manufactured in bulk, molybdenum
disulfide is cheaper than silicon and opens the door to the potential for
cheaper energy from the sun.
