How the Berry Solar Cell Works

by Jimmy O'Dea Cornell University

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Teachers: for a lending kit to build the berry solar cell in your classroom, see: http://www.ccmr.cornell.edu/education/lendinglibrary/

How the Berry Solar Cell Works

any How the Berry Solar Cell Works

any How the Berry Solar Cell Works

First, let's talk about how any solar cell works…

A solar cell is a device that converts the energy in light into electricity

A solar cell is a device that converts the energy in light into electricity.

A solar cell is a device that converts the energy in light into electricity.

Let's see how this works...

any How the Berry Solar Cell Works

Energy from light (made up of photons)

excites electrons in atoms in the solar cell.

any How the Berry Solar Cell Works

any How the Berry Solar Cell Works

Energy from light (made up of photons)

excites electrons in atoms in the solar cell.

Energy from light (made up of photons)

excites electrons in atoms in the solar cell.

any How the Berry Solar Cell Works

any How the Berry Solar Cell Works

We can collect the excited and route them through a device we want to power, like a light bulb.

We can collect the excited and route them through a device we want to power, like a light bulb.

any How the Berry Solar Cell Works

any How the Berry Solar Cell Works

When the negatively charged leave the solar cell, positive charges are left behind.

any How the Berry Solar Cell Works

When the negatively charged leave the solar cell, positive charges are left behind.

are attracted to and flow to the ( ) charge. +

any How the Berry Solar Cell Works

are attracted to and flow to the ( ) charge.

The flow of is what we call electricity!

When the negatively charged leave the solar cell, positive charges are left behind.

+

How the Berry Solar Cell Works

Now to the berry solar cell…

How the Berry Solar Cell Works

So if we want to use light to create flowing , we first need a material that absorbs light. This is what the berry juice will do.

How the Berry Solar Cell Works

So if we want to use light to create flowing , we first need a material that absorbs light. This is what the berry juice will do.

How the Berry Solar Cell Works

There are many different molecules in berry juice (such as H2O). The molecule that absorbs

the light in berry juice is called cyanidin.

How the Berry Solar Cell Works

There are many different molecules in berry juice (such as H2O). The molecule that absorbs

the light in berry juice is called cyanidin.

How the Berry Solar Cell Works

When the berry juice absorbs light, an in the berry juice molecule is excited. For this excited to be of any use, we need to quickly “pull” it away from the berry juice molecule. We do that with a chemical called titanium dioxide.

How the Berry Solar Cell Works

When the berry juice absorbs light, an in the berry juice molecule is excited. For this excited to be of any use, we need to quickly “pull” it away from the berry juice molecule. We do that with a chemical called titanium dioxide.

How the Berry Solar Cell Works

When the berry juice absorbs light, an in the berry juice molecule is excited. For this excited to be of any use, we need to quickly “pull” it away from the berry juice molecule. We do that with a chemical called titanium dioxide.

Now we need something that will collect the from the titanium dioxide. This something is called an electrode. Our electrode is a glass slide with a conductive and transparent coating.

How the Berry Solar Cell Works

Now we need something that will collect the from the titanium dioxide. This something is called an electrode. Our electrode is a glass slide with a conductive and transparent coating.

How the Berry Solar Cell Works

Now we need something that will collect the from the titanium dioxide. This something is called an electrode. Our electrode is a glass slide with a conductive and transparent coating.

How the Berry Solar Cell Works

Now we need something that will collect the from the titanium dioxide. This something is called an electrode. Our electrode is a glass slide with a conductive and transparent coating.

How the Berry Solar Cell Works

Now we need something that will collect the from the titanium dioxide. This something is called an electrode. Our electrode is a glass slide with a conductive and transparent coating.

How the Berry Solar Cell Works

Now we need something that will collect the from the titanium dioxide. This something is called an electrode. Our electrode is a glass slide with a conductive and transparent coating.

How the Berry Solar Cell Works

Fluorine doped tin oxide coating on a glass slide. Image: Jimmy O’Dea

500 nm

Here's what the coating on the glass slide looks like under an electron microscope at x20,000 magnification.

How the Berry Solar Cell Works

How the Berry Solar Cell Works

Our collected flow through our light bulb and into an electrode at the other side of the solar cell.

How the Berry Solar Cell Works

But taking from the berry juice molecules makes them positively charged and less likely to give up another .

How the Berry Solar Cell Works

So we replenish the berry juice molecules with through a chemical reaction with a solution of iodide.

How the Berry Solar Cell Works

So we replenish the berry juice molecules with through a chemical reaction with a solution of iodide.

How the Berry Solar Cell Works

But this reaction is slow, so we speed it up (catalyze it) with a coating of carbon (from either candle soot or a graphite pencil).

How the Berry Solar Cell Works

But this reaction is slow, so we speed it up (catalyze it) with a coating of carbon (from either candle soot or a graphite pencil).

How the Berry Solar Cell Works

But this reaction is slow, so we speed it up (catalyze it) with a coating of carbon (from either candle soot or a graphite pencil).

How the Berry Solar Cell Works

But this reaction is slow, so we speed it up (catalyze it) with a coating of carbon (from either candle soot or a graphite pencil).

How the Berry Solar Cell Works

But this reaction is slow, so we speed it up (catalyze it) with a coating of carbon (from either candle soot or a graphite pencil).

How the Berry Solar Cell Works

And that's how the berry solar cell works!