LISA VAN PAY: So here's the sun, right?
It's about 93 million miles away from the Earth. It's big and it's got a lot of energy.
Light is how energy moves through space. But the snag is when light hits the Earth, the energy
is all spread out so we have to figure out how to
collect it and concentrate it so we can use it.
To get lots of power, we use solar farms. On some farms, thousands of mirrors focus sunlight to
heat pipes filled with fluid. On others, rotating mirrors aim the sun's rays at a
liquid-filled tank at the top of a tower. Both convert heat energy to electricity
using a generator. And then there are huge farms of solar cells
collecting the sun's energy and turning it directly into electricity.
But solar cells can work on a smaller scale too powering everything from street lights to houses
to stores, even airports.
But what about flexible cells? They'd go where you go.
Then you could charge your cellphone while you're on your way to meet a friend.
Researchers at Arizona State University are looking to the solar experts, plants, to see if we can make solar
cells that work better with your life.
Brad, can you tell me a little bit about what kind of research you're doing in your lab?
BRAD BRENNAN: Our group likes to focus on the first steps of photosynthesis where plants take light
and start converting it into energy.
LISA VAN PAY: In the plant, chlorophyll molecules absorb light from sun and use
that energy to move around electrons. Solar cells based on photosynthesis can be smaller,
cheaper and more flexible than the ones we have now.
Most of the solar cells we use now are made from layers of silicon engineered to make them
positive or negative. When the layers are sandwiched together, the space
in between acts kind of like a magnet. Light energy can excite electrons making them jump
into the in-between space and its magnetic properties push them to the other side.
Once the electrons build up, the negative charge makes them push each other through the circuit,
creating an electrical current we can use. Brad is making colored dyes that help the solar cell
absorb even more light energy like chlorophyll does in plants.
BRAD BRENNAN: We make more and more complex molecules for us to eventually try and get
a very good mimic of what the plant does.
LISA VAN PAY: So what are we looking at here?
BRAD BRENNAN: We're looking at different pieces of a dye-sensitized solar cell showing kind of the
different parts to form our solar cell. We have a very, very thin film on that.
We cover that film with one of the dyes that we make. It absorbs light very well and if we clipped 2 wires
to those pieces of glass and put it in the sunlight, we'd be getting electricity out of that.
It's basically it's a step-wise process in research, you just never know what's gonna work
and what doesn't work.
LISA VAN PAY: In this case, you might need to collaborate with some other people that could give
you ideas on how to do that?
BRAD BRENNAN: A lot of people have different specialties and they might be 10,000 miles away on
the other side of the Earth, at a different university, but they know how to solve your problem.
LISA VAN PAY: Collaboration is an important part of solving problems.
Remember that thin film Brad was talking about?
That's another thing that researchers are working to improve.
So Britney, can you tell me a little bit about the work that you're doing in the lab right now?
BRITTANY LYNN: The goal of the lab right now is to make organic solar cells more efficiently.
And the work that I was doing to help this along the was to take certain layers on a solar cell and try to
make it so that they were bumpy. And what being bumpy does is it helps the interface
between 2 surfaces have more surface area.
LISA VAN PAY: So there's more surface area but the 2 surfaces still have to be close enough together
for the electrons to travel?
BRITTANY LYNN: Oh, yes, so they are limited in a distance they can move by the material that we're
using, so we have to make really thin solar cells. But when it's really thin, you can see through it
more easily. And so if you can see through it that means the light
is not getting absorbed by the material. So what we wanna do is be able to have it thicker
so more is absorbed in the sunlight and you get more power.
I wanted to do some work over the summer that would give me some experience in the chemistry lab so I
could actually touch some of the machines that we're learning about in class and also to work with
solar cells because that's a big field optics and science.
LISA VAN PAY: Everyday, the Earth receives a huge amount of energy from the sun.
And everyday, we're getting better at harnessing that energy.
New ideas are shared every summer as students from over the world participate in the Solar Decathlon,
a competition to see who can make the best solar-powered house.
Soon photovoltaic shingles for your house and light flexible cells that can charge your stuff on the
move will be everywhere. And someday, we might even have solar-power
beam down from satellites. The National Science Foundation supports researchers
who look at stuff we already know a lot about like plants and solar cells and think about them in
new ways. New ideas that could lead to a brighter tomorrow.