by Preston Sims, student writer
|Studies show that spinach may be used for more
than spoiling mealtime for children.
Researchers from the Massachusetts Institute of Technology (MIT)
have discovered a way to use spinach’s photosynthetic ability
to convert sunlight energy into a form that may be able to power
The device is called the “spinach sandwich”. This
mechanism will work like a battery and is fueled by the protein
complex Photosystem I (PSI) which is derived from the chloroplast
in ground-up spinach leaves. PSI is only 10 to 20 nanometers
wide. It would take over 100,000 of these microscopic protein
complexes to cover the head of a needle.
Marc A. Baldo, assistant professor of electronic engineering
and computer science at MIT, told MIT Tech Talk, “They
are the smallest electronic circuits I know of.”
The “spinach sandwich” is made up of several different
layers to increase its efficiency. The bottom layer is a transparent
glass coat with a conductive material. On top of this is a thin
layer of gold to help the chemical reaction that assembles PSI.
Next, there is a soft organic semiconductor that prevents electrical
shorts and protects the protein complexes. The top of the sandwich
is a thin layer of metal.
Due to the fact that electronics must be kept dry and the spinach
proteins need water, researchers had to come up with a compromise.
This problem was resolved by combining the electronic and organic
materials with detergent peptides, which store moisture for the
Shuguang Zhang, Ph.D., associate director of the Center for Biomedical
Engineering at MIT told MIT Tech Talk, “Detergent peptide
turned out to be a wonderful material to keep proteins intact
on the surface with electronics. The detergent materials may
contain some trapped water, which acts like the oils that help
plant seeds survive in droughts.”
Researchers are enthusiastic to harvest this technology because
spinach is able to produce a massive amount of energy relative
to its size and weight.
The latest test of this device showed promising results. A laser
light was shone on the device to create optical excitation. Twelve
percent of the laser’s light was converted directly to
an electrical charge.
Researchers hope to eventually create a 20 percent or more conversion
rate by using multiple layers of PSI or 3-D surfaces. A 20 percent
rate would create an energy source powerful enough for many portable
electronics such as cell phones or laptops.
Although this technology may not be available anytime soon, it
is still a promising possibility for the future.
Some day we could be walking down the street listening to spinach-powered