How to Make a Solar Cell

Last Updated: 5 March, 2019 by Alexander Thomas

How to Make a Solar Cell

Given our current global climate crisis and the damage we have thus far caused to our environment, it’s very likely that a great number of households will soon switch to solar energy worldwide. In fact, this type of renewable energy will likely play an important role in the future of humanity, so why not get on board early on?

By learning how to make a solar cell, you can discover the basics of solar energy and achieve a better understanding of the solar energy system that might one day power your home or business. Although a home made solar cell will not be effective enough to power light bulbs, let alone appliances, making one can be a fun experiment, as well as a successful school project.

How to Make a Solar Cell in 4 Steps

You can learn how to make a solar cell from various types of materials that display the photovoltaic effect (described below). Home made solar cells often use sheets of copper, but in what follows, we describe the making of a solar cell with conductive glass, which is slightly more efficient and certainly more aesthetic.

Step 1: Gather Your Materials

The first step to making your own solar cells is buying and gathering your materials and tools. For this type of home made solar cell, you’ll need the following things:

  • Conductive glass plates, which will serve as the basic photovoltaic surfaces in your cell
  • Alcohol (preferably ethanol) for treating the plates
  • Titanium dioxide solution, also used in treating the plates
  • A carbon graphite pencil
  • Transparent tape and binder clips for assembling the cell
  • A petri (or similarly shallow) dish
  • De-ionized water
  • An electric hot plate for cooking the plates
  • Iodide solution to create an electrolyte
  • Voltmeter or multimeter to test the cell once it is completed and exposed to sunlight
  • Alligator clips to connect the cell to a multimeter

Most of these materials are easy to find at the local hardware store, in pharmacies, and online. All you need for this PV cell is fairly affordable, apart from the conductive glass plates, which might be slightly more expensive than everything else.

Step 2: Prepare the Glass Plates

Coating your glass plates is the most intricate part of making solar cells. The plates should be roughly the size of two microscope slides and both surfaces of each plate should be thoroughly cleaned using ethanol (or other types of alcohol).

Next, you need to find out which sides of these plates are conductive and which are not. To do so, verify each side using a multimeter by touching it to the device’s leads. Place one plate so that its conductive side faces up and the other plate with its conductive side down.

Treat the surfaces you can see from both plates using titanium dioxide previously diluted in a solution. Only two drops should suffice for each surface. Overnight, put the plate with its conductive side up on a hot plate to cook the titanium dioxide. The other plate should be cleaned and stored some place where it won’t get dirty.

The next day, fill a shallow petri dish with dye (from hibiscus tea, raspberries, or pomegranate juice) and soak the plate you’ve just cooked with its coated side down. Meanwhile, use alcohol to clean the other plate once again. Then, retest this plate for conductivity with a multimeter and mark its non-conductive surface with a “+”. Cover the other surface with a thin carbon coating using graphite lubricant or running over it with a pencil.

It’s finally time to remove the coated plate from the dish and clean it twice – once using de-ionized water, then with alcohol. Once both plates are dry, you’re ready for the next step – the assembly.

Step 3: Assemble the Solar Cell

The two plates should come together so that their different coatings touch one another. Instead of overlapping them perfectly, however, make sure they are just 5mm or 0.2in offset. While holding them in this position, use your binder clips on two of the edges so that they are held in place moving forward.

Since the plates are slightly offset, you’ll be able to see 5mm of one of the coated sides. On this visible side, place two drops of iodide solution and let it soak so that it eventually covers both coated sides. The solution will act as an electrolyte when the cell is exposed to sunshine by allowing electrons to move from one plate to the other. If any excess solution makes its way on other surfaces, make sure to wipe it off.

At this point, you’ve already learned the basics of making solar cells. All that’s left to do is to expose your PV cell to sunlight and test whether it actually generates any electricity.

Step 4: Test Your Solar Cell

On two sides of the cell, you’ll notice that the coatings are slightly exposed due to the offset positioning of the two plates. To both of these visible coated surfaces, attach an alligator clip. To connect the cell to a multimeter, note that the latter has two wires – a black one and a red one.

Using the alligator clips, touch the multimeter’s black wire to the titanium dioxide coating, which will act as the cell’s cathode (or negative electrode). The red wire should connect to the carbon coating or the cell’s anode (positive electrode, also marked with a “+” in a previous step).

Finally, it’s time to expose your home made solar cell to a light source. If you’re at home, it’s most convenient to place the cell under a lamp or, for better results, with the negative side facing direct sunlight. If, however, you’re demonstrating the effectiveness of the cell in a classroom or at a fair, you can place it on top of an overhead projector for a similar effect.

To observe how the PV cell works, use your multimeter to measure its amperage both before and after you expose it to a light source.

How to Make a Solar Cell: Buying the Materials

There are two types of solar cells you can easily make at home, but the building process and the materials you’ll need to make either will differ quite a bit depending on your choice. The copper installation is overall easier to make and purchasing the materials is as straightforward as taking a trip to your local hardware shop. For the copper version, all you need is a sheet of flashing copper, a transparent CD case (or large plastic bottle with its top half cut off), pure baking soda, a solder, hot-melt adhesive (hot glue), metal shears, an electric wire, and an electric stove top.

On the other hand, a glass solar cell requires titanium dioxide, which easy to come by on popular Internet retailers. To complete this home made solar cell, you will need at least two small squares of conductive glass in the size of 1 by 1 inches (2 for each cell you want to make), ethanol to wipe the glass clean, a hot plate, raspberry juice or tea that is high in anthocyanins, binder clips, a lighter, and a triiodide solution (you can mix 3 parts iodine with 1 part alcohol). While both options are accessible ways to making your solar cells, the glass cell is the closest thing you can make that resembles the real deal and its voltage will also be higher.

How Does a Home Made Solar Cell Work?

If you want to learn how to make a solar cell, it’s a good idea to first find out how one works. In a copper cell, cuprous oxide is a semiconductor, which is somewhere between a conductor and an insulator. This means that some of the electrons in the material have the potential to flow freely as a result of the energy provided by sunlight. For this home made solar cell, the electrons freed by the sun’s energy move into the saltwater and then into the other sheet of copper. 

The glass alternative substitutes the silicon from a regular PV cell with a dye-sensitized titanium dioxide. Albeit less efficient, both this version and the copper cell are far cheaper to manufacture, which makes them great ideas for a science fair entry. In this instance, the installation works in the following manner: the dye absorbs the light and the anthocyane compound transfers its electrons to the semiconductive titanium dioxide solution, while the latter separates the charge. The carbon soot layer you add to the glass acts as a catalyst and facilitates this transfer of electrons. The reduction-oxidation couple completes the circuit.

Can You Use a Home Made Solar Cell?

No home made solar cell can ever hope to compare to those that are factory-made. From the semiconductor to the glass and the catalyst, all of the materials used to make commercially available photovoltaic panels are just way too expensive. The most energy you can hope to get from your own solar cell is just over 100 microamps. Unfortunately, this is not even enough to power a small LED light. If you’re looking to make your own solar cells in order to get free energy, this is definitely not the way.

Given this, the best possible use that can come out of making solar cells yourself is the educational potential. Regardless of what type of project you choose, you’ll learn a lot about how semiconductors work, as well as gain a better understanding of why we need sustainable sources of energy. Lastly, this can be a great idea for a science project. You can help your child make either or both cells and then test it out to see which one is more effective. If nothing else, doing this for a science fair can be a lesson in self-reliance. As it turns out, the desire for independence and self-sufficiency seem to be at the forefront of the DIY culture growth in the past few years.

Are Home Made Solar Cells Cost-Effective?

Good conductive glass does not come cheap, and neither does the catalyst. This is the case in both versions of the cell, as we’re basically using the soot that stains the glass when we pass it through an open flame like a catalyst, which is possible due to its carbon composition. Materials that are superior to what you’ve already used when making your own solar cells would be way too expensive to be worth the trouble. Although you can use them for fun, the fact that these installations are not even able to power a single LED light, let alone a bulb for a lamp, make them quite ineffective.

The big advantage here is that both the glass and the copper solar cell are incredibly cheap to make. If you already have the tools, your final expenses should not exceed $15 or less. Having said this, these minimal costs are clearly outweighed by the knowledge potential that the project has to offer. A cost-effective installation would mean for you to purchase the cells already made, as they have a relatively high efficiency at capturing sunlight and generating electricity, and couple them in one or several panels. You could also save a lot of money by buying the panels already made and installing them yourself.

How to Make a Solar Cell: Summary

Despite the fact that many still chose to turn a blind eye to climate change, the sources of energy we currently use the most are definitely playing a major part in the current global crisis. Learning how to make a solar cell by yourself or with your children is a game-changing activity that will help you both get acquainted with what it means to create and use renewable energy. It’s not easy, nor particularly cheap to buy, but it is far better for the environment than what we currently have. You’d be part of the change that we need to keep nature clean.

More importantly, this project opens up the possibility to discuss energy consumption and efficiency, which is particularly helpful when you’re trying to either learn or teach someone about what it means to have a carbon footprint and to become energy independent, while also cultivating a mindset that is based on self-reliance. Making solar cells at home won’t lower your electricity bill, nor will it be able to power an appliance. However, it is a fun and cost-effective way to learn about solar technology. Furthermore, it is an easy and rewarding DIY project you can finish in just a couple of hours.