A North
Carolina State University researcher and his team has proved
that "artificial
leaves", which are water-gel-based solar mechanisms,
can create electricity just like solar cells. In addition, they are
much greener than silicon-based solar cells and could be less
expensive.
Dr.
Orlin Velev, lead author of the study and Invista Professor of
Chemical and Biomolecular Engineering at NC State, created artificial
leaves with the idea of using solar cells to imitate nature more
closely.
Velev
accomplished this by infusing water-based gel with light-sensitive
molecules, and pairing it with electrodes coated by materials such as
graphite or carbon nanotubes. The sun's rays then excite the
light-sensitive molecules, creating electricity. This closely
resembles nature because plant
molecules get excited in order to synthesize sugars needed
to grow.
Also,
in order to draw in solar energy the way nature does, natural
products like chlorophyll can be used in the artificial leaves to
replace synthetic light-sensitive molecules to create the same
reaction. The water-gel matrix in these new leaves allows for both
natural products like chlorophyll and synthetic light-sensitive
molecules to be used interchangeably.
"The
next step is to mimic the self-regenerating mechanisms found in
plants," said Velev. "The other challenge is to change the
water-based gel and light-sensitive molecules to improve the
efficiency
of the solar cells."
While
the short-term goal would be to make these water-based photovoltaic
devices more plant-like and realistic to nature, the long-term goal
is to have residential and commercial roofs covered in soft sheets of
the artificial-leaf solar cells. But Velev warns that such a concept
is years into the future.
"We
do not want to overpromise at this stage, as the devices are still of
relatively low efficiency and there is a long way to go before this
can become a practical technology," said Velev. "However,
we believe that the concept of biologically inspired 'soft' devices
for generating electricity may in the future provide an alternative
for the present-day solid-state technologies."
This
study, titled "Aqueous soft matter based photovoltaic
devices," was published in Journal
of Materials Chemistry this
month.
