We discuss and comment on the role agriculture will play in the containment of the CO2 problem and address protocols for terraforming the planet Earth.
A model farm template is imagined as the central methodology. A broad range of timely science news and other topics of interest are commented on.
Saturday, June 2, 2012
Graphene Solar Cell Efficiency at 8.6%
This shows us that graphene based solar cells are plausibly simple to
create and produce. The transparency also provide additional
flexibility in terms of design. One step up from this and we
certainly have a commercial product.
I suspect we are close to a design revolution in solar capture
architecture that will give us light efficient solar energy
conversion. It has been a long wait however.
This also shows us that graphene work continues to advance rapidly
and astonishingly, no serious impediments have arose to stall us.
The next five years will see all this flow into the market place.
I notice that absolutely no one dares suggest something is impossible
in terms of technology anymore. It took decades, but they are
finally all cowed
Florida physicists set new record for graphene solar cell efficiency
Doping may be a no-no
for athletes, but researchers in the University of Florida's physics
department say it was key in getting unprecedented power conversion
efficiency from a new graphene solar cell created in their lab.
Graphene solar cells
are one of industry's great hopes for cheaper, durable solar power
cells in the future. But previous attempts to use graphene, a
single-atom-thick honeycomb lattice of carbon atoms, in solar cells
have only managed power conversion efficiencies ranging up to 2.9
The UF team was able
to achieve a record breaking 8.6 percent efficiency with their device
by chemically treating, or doping, the graphene with
trifluoromethanesulfonyl-amide, or TFSA. Their results are published
in the current online edition of Nano Letters.
"The dopant makes
the graphene film more conductive and increases the electric field
potential inside the cell," said Xiaochang Miao, a graduate
student in the physics department. That makes it more efficient at
converting sunlight into electricity. And unlike other dopants that
have been tried in the past, TFSA is stable - its effects are long
The solar cell that
Miao and her co-workers created in the lab looks like a 5-mm-square
window framed in gold. The window, a wafer of silicon coated with a
monolayer of graphene, is where the magic happens.
Graphene and silicon,
when they come together, form what is called a Schottky junction - a
one-way street for electrons that when illuminated with light, acts
as the power conversion zone for an entire class of solar cells.
Schottky junctions are commonly formed by layering a metal on top of
a semiconductor. But researchers at the UF Nanoscience Institute for
Medical and Engineering Technologies discovered in 2011 that
graphene, a semi-metal, made a suitable substitute for metal in
creating the junction.
unlike conventional metals, is transparent and flexible, so
it has great potential to be an important component in the kind of
solar cells we hope to seeincorporated into building exteriors and other materials in
the future," said Arthur Hebard, distinguished professor of
physics at UF and co-author on the paper.
"Showing that its
power-converting capabilities can be enhanced by such a simple,
inexpensive treatment bodes well for its future."
The researchers said
that if graphene solar cells reach 10 percent power conversion
efficiency they could be a contender in the market place, if
production costs are kept low enough.
The prototype solar
cell created in the UF lab was built on a rigid base of silicon,
which is not considered an economical material for mass production.
But Hebard said that he sees real possibilities for combining the use
of doped graphene with less expensive, more flexible substrates like
the polymer sheets currently under development in research
laboratories around the world.