How Does a Solar Panel Work? | Solar Panel Types

What is a Solar Panel?

A Solar panel (also known as a “PV panel”) is a device that converts light from the sun, which is composed of particles of energy called “photons”, into electricity that can be used to power electrical loads.

Solar panels can be used for a wide variety of applications including remote power systems for cabins, telecommunications equipment, remote sensing, and of course for the production of electricity by residential and commercial solar electric systems.

On this page, we will discuss the history, technology, and benefits of solar panels. We will learn how solar panels work, how they are made, how they create electricity, and where you can buy solar panels.

A Short History of Solar Panels

Solar energy was used by humans as early as the 7th century B.C. when humans used sunlight to light fires by reflecting the sun’s rays onto shiny objects.

Later, in 3rd century B.C., the Greeks and Romans harnessed solar power with mirrors to light torches for religious ceremonies.

In 1839 and at the age of just 19, French physicist Edmond Becquerel discovered the photovoltaic (PV) effect while experimenting with a cell made of metal electrodes in a conducting solution.

He noted that the cell produced more electricity when it was exposed to light – it was a photovoltaic cell.

In 1954 PV technology was born when Daryl Chapin, Calvin Fuller and Gerald Pearson developed the silicon PV cell at Bell Labs in 1954 – the first solar cell capable of absorbing and converting enough of the sun’s energy into power to run everyday electrical equipment.

Today satellites, spacecraft orbiting Earth, are powered by solar energy.

How do solar panels work?

Simply put, a solar panel works by allowing photons, or particles of light, to knock electrons free from atoms, generating a flow of electricity.

Solar panels actually comprise many, smaller units called photovoltaic cells. (Photovoltaic simply means they convert sunlight into electricity.) Many cells linked together make up a solar panel.

Each photovoltaic cell is basically a sandwich made up of two slices of semi-conducting material, usually silicon the same stuff used in microelectronics.

To work, photovoltaic cells need to establish an electric field. Much like a magnetic field, which occurs due to opposite poles, an electric field occurs when opposite charges are separated.

To get this field, manufacturers “dope” silicon with other materials, giving each slice of the sandwich a positive or negative electrical charge.

Specifically, the seed phosphorous into the top layer of silicon, adds extra electrons, with a negative charge, to that layer. Meanwhile, the bottom layer gets a dose of boron, which results in fewer electrons, or a positive charge.

This all adds up to an electric field at the junction between the silicon layers. Then, when a photon of sunlight knocks an electron free, the electric field will push that electron out of the silicon junction.

A couple of other components of the cell turn these electrons into usable power. Metal conductive plates on the sides of the cell collect the electrons and transfer them to wires. At that point, the electrons can flow like any other source of electricity.

Recently, researchers have produced ultrathin, flexible solar cells that are only 1.3 microns thick about 1/100th the width of a human hair and 20 times lighter than a sheet of office paper.

There are other types of solar power technology, including solar thermal and concentrated solar power (CSP) which operate in a different fashion than photovoltaic solar panels, but all harness the power of sunlight to either create electricity or heat water or air.

Types of Solar Panel

There are three major types of solar panels: monocrystalline, polycrystalline, and thin-film.

Each type has its own unique advantages and disadvantages, and the solar panel type best suited for your installation will depend on factors specific to your own property and desired system characteristics.

#1. Monocrystalline Solar Panel.

These solar panels are made using thin wafers of silicon, which are extracted from artificially grown crystals. Single crystals developed in isolation help to form these cells and make them the most efficient.

This is why these are the most expensive among the other types. Compared to their counterpart polycrystalline cells, monocrystalline solar cells are about 35% more expensive and provide an efficiency rate between 15–24%.

#2. Polycrystalline Solar Panel.

Polycrystalline solar panels are a newer development in the different types of solar panels, but they are rising quickly in popularity and efficiency. Just like monocrystalline solar panels, polycrystalline cells are made from silicon.

But polycrystalline cells are made from fragments of the silicon crystal melted together.

During the manufacturing process, the silicon crystal is placed in a vat of molten silicon. Instead of pulling it out slowly, this crystal is allowed to fragment and then cool.

Then once the new crystal is cooled in its mold, the fragmented silicon is thinly sliced into polycrystalline solar wafers. These wafers are assembled together to form a polycrystalline panel.

Polycrystalline cells are blue in color because of the way sunlight reflects on the crystals. Sunlight reflects off of silicon fragments differently than it does with a pure silicon cell.

Usually, the back frames and frames are silver with polycrystalline, but there can be variations. The shape of the cell is square, and there are no gaps between the corners of the cells.

#3. Thin-film solar panel.

If you’re looking for a more cost-effective option, consider thin films. Thin-film solar modules are made by placing one or more films of photovoltaic material (such as silicon, cadmium or copper) on a substrate.

These types of solar modules are the easiest to manufacture and, due to economies of scale, cheaper than the alternatives, as less material is required to manufacture them.

They are also flexible, which opens up many possibilities for alternative applications and is less affected by high temperatures. The main problem is that they take up a lot of space and are generally unsuitable for residential installations.

In addition, they offer the shortest guarantees, as their lifespan is shorter than that of mono- and polycrystalline solar modules. However, they can be a good option to choose between the different types of solar panels that have plenty of space.

#4. Amorphous Solar Panel.

The cheapest form of solar cell is an amorphous solar cell. These are newly launched cells that are manufactured in a unique way. They avoid the use of crystals. Instead, their production process involves thin silicon deposits on the backing substrate.

Amorphous solar cells provide two major benefits, ie. Flexibility in solar cells with its extremely thin silicon layer, and high efficiency in low levels of light during winter.

But, while these promise the above benefits, they also compromise efficiency. They provide the lowest efficiency rates of 7% – 9% compared to the other two variants. Thus, they require about twice the panel area to give the same output.

Until now, they do not even have an approved production technology in the industry, and therefore, they are less robust than the other two types of solar panels.

#5. Biohybrid Solar Panel.

It is not a completely solar cell, but a hybrid solar cell is a mixture of monocrystalline solar cells and amorphous solar cells. Hybrid solar cells are called HET (heterojunction with intrinsic thin layer) solar cells.

Compared to each individual type of solar cell, the hybrid type is the most efficient due to the combination of the power of the two solar cells. These work best during sunny seasons, ie beyond the 250C temperature. In view of the same, this helps generate about 10% more electricity.

If one has to choose the best, polycrystalline cells prove to be the most suitable for most installations due to their value for money, design, and efficiency rate.

How efficient are different types of solar panels?

Each type of solar panel varies in how much power it can produce. If you have limited roof space, choose a high-efficiency solar panel to get the most out of your system.

Crystalline solar panels: Middle- to high-efficiency

Monocrystalline panels typically have the highest efficiency and power capacity. They can reach efficiencies of over 22% and provide over 300 watts (W) of power capacity.

Many even exceed 400 W. Polycrystalline solar panels, on the other hand, rarely exceed 17% efficiency and tend to have lower wattages.

Monocrystalline solar panels also tend to perform better than polycrystalline panels in warm temperatures. They usually have lower temperature coefficients, which means they maintain higher efficiencies when it’s hot outside.

While they differ in performance, monocrystalline and polycrystalline panels are about the same size physically. Both types of solar panels tend to come in 60, 72, and 96 silicon cell options.

Thin-film solar panels: Usually low-efficiency

Thin-film solar panels have lower efficiencies and power capacities than monocrystalline or polycrystalline panels. Efficiencies vary based on the specific material used in the cells, but thin-film solar panels tend to be around 11% efficiency.

Thin-film solar cell technology does not come in uniform sizes. The power capacity from one thin-film panel to another largely depends on its physical size.

Generally, the power capacity per square foot of monocrystalline or polycrystalline solar panels will exceed that of thin-film panels.

What type of panel is best for your installation?

Monocrystalline, polycrystalline, and thin-film panels each have advantages and disadvantages, and the solution you should move forward with depends on your property and your savings goals.

If you have a lot of space for solar panels, you can save money upfront by installing lower-efficiency, lower-cost polycrystalline panels.

If you have limited space and want to maximize your electric bill savings over 20 years, we recommend high-efficiency, monocrystalline solar panels.

As far as thin-film panels go, it’s most common to choose this type of solar panel if you’re installing a portable or DIY solar system, like on an RV or boat.

Businesses also use thin-film panels for large, commercial roofs that can’t handle the additional weight of traditional solar equipment.

These roofs can also afford the lower efficiencies of thin-film panels because they have more roof space.

FAQs.