Rice University researchers and members of Girl Scouts of America Troop 25080 confirm the conductivity of graphene made from shortbread Girl Scout Cookies. Credit: Rice University |
Scientists can make graphene out of just about anything with carbon?even Girl Scout Cookies.
Graduate
students in the Rice University lab of chemist James Tour proved it
when they invited a troop of Houston Girl Scouts to their lab to show
them how it’s done.
The
work is part of a paper published online today by ACS Nano. Rice
scientists described how graphene?a single-atom-thick sheet of the same
material in pencil lead?can be made from just about any carbon source,
including food, insects and waste.
The cookie gambit started on a dare when Tour mentioned at a meeting that his lab had produced graphene from table sugar.
“I
said we could grow it from any carbon source?for example, a Girl Scout
cookie, because Girl Scout Cookies were being served at the time,” Tour
recalled. “So one of the people in the room said, ‘Yes, please do it.
… Let’s see that happen.'”
Members
of Girl Scouts of America Troop 25080 came to Rice’s Smalley Institute
for Nanoscale Science and Technology to see the process. Rice graduate
students Gedeng Ruan, lead author of the paper, and Zhengzong Sun
calculated that at the then-commercial rate for pristine graphene?$250
for a two-inch square?a box of traditional Girl Scout shortbread cookies
could turn a $15 billion profit.
“That’s a lot of cash!” said an amazed Sydney Shanahan, a member of the troop.
A sheet of graphene made from one box of shortbread cookies would cover nearly 30 football fields, Sun said.
The
experiment was a whimsical way to make a serious point: that
graphene?touted as a miracle material for its toughness and conductivity
since its discovery by Nobel Prize-winning scientists Andre Geim and
Konstantin Novoselov in 2004?can be drawn from many sources.
To
demonstrate, the researchers subsequently tested a range of materials,
as reported in the new paper, including chocolate, grass, polystyrene
plastic, insects (a cockroach leg) and even dog feces (compliments of
lab manager Dustin James’ miniature dachshund, Sid Vicious).
In
every case, the researchers were able to make high-quality graphene via
carbon deposition on copper foil. In this process, the graphene forms
on the opposite side of the foil as solid carbon sources decompose; the
other residues are left on the original side. Typically, this happens in
about 15 minutes in a furnace flowing with argon and hydrogen gas and
turned up to 1,050 degrees Celsius.
Members of Girl Scouts of America Troop 25080 of Houston look at fresh graphene, just out of the furnace and attached to a piece of copper. The troop visited a Rice University lab to watch researchers make graphene, a single-atom-thick sheet of carbon out of Girl Scout Cookies. Credit: Rice University |
Tour
expects the cost of graphene to drop quickly as commercial interests
develop methods to manufacture it in bulk. Another new paper by Tour and
his Rice colleagues described a long-sought way to make graphene-based
transparent electrodes by combining graphene with a fine aluminum mesh.
The material may replace expensive indium tin oxide as a basic element
in flat-panel and touch-screen displays, solar cells and LED lighting.
The
experiment the Girl Scouts witnessed “has a lot to do with current
research topics in academia and in industry,” said Tour, Rice’s T.T. and
W.F. Chao Chair in Chemistry as well as a professor of mechanical
engineering and materials science and of computer science. “They learned
that carbon?or any element?in one form can be inexpensive and in
another form can be very expensive.”
Diamonds are a good example, he said. “You could probably get a very large diamond out of a box of Girl Scout Cookies.”
Zhiwei Peng a graduate student in Tour’s group, is a co-author of the paper.
Sandia
National Laboratory, the Air Force Office of Scientific Research and
the Office of Naval Research MURI program funded the research.
