How Do Solar Panels Work?

When talking about solar power the conversation usually ends at the fact it is a renewable energy source, so just how do solar panels work? The basic gist is that thermal energy from the sun is converted into usable electricity via photovoltaic cells. However, this alone is a complex process.

If you ask an expert “how do solar panels work?” then you’re likely to get lost in the explanation unless you’re familiar with conductivity and atoms. As such, before you can understand how solar panels work, you need to understand what they’re made of and how these materials are affected by sunlight.

How do Solare panels work 'Short Version'

Light from the sun, containing photons, hits your solar panels.
The properties of semiconductive materials within the solar cells draw these photons into them.
Energy from the photons is transferred into electrons within the cells.
As this energy builds electrons trapped in the p-n junction become so “charged” that they enter the conduction band.
Electrons in the conduction band are able to leave the p-n junction, leaving an electron hole in their place.
As the conduction band electrons and holes move an electrical current is created.
Sandwiching both sides of the semiconductor material is a layer of conductive material which “collects” the energy produced.
Energy collected in the conductive layer is stored as direct current (DC) and isn’t compatible with the majority of devices, or the national grid.
A solar inverter takes in this DC current and converts it into alternating current (AC), with an efficiency of around 90%.
Congratulations! You now have a source of usable electrical energy that has come from the sun, all thanks to your solar panel setup! You also have an answer if somebody asks YOU “how do solar panels work?”

What Are Photovoltaic Cells?

Solar panels are almost always made up of something called photovoltaic cells, otherwise known as PVC. This is why you might see reference to PV/ PVC solar panels when browsing renewable energy sites. This distinction is made to separate PV/ PVC solar panels, which generate electricity, from solar thermal panels, which heat a household’s water.

There are a few different types of photovoltaic cells but they all work in a similar way. PV solar panels use semiconductors to catch incoming photons from the sun and convert them into usable electricity. This is known as the photovoltaic effect.

What is a semiconductor?

Semiconductors are elements or compounds that can only conduct electricity sometimes. To achieve electrical conductivity certain conditions have to be met. For example: the element or compound needs to be receiving energy from another source, like sunlight.

This is because the conductivity of a semiconductor is affected by the amount of infrared radiation, ultraviolet radiation, or visible light touching it. Which is part of the reason why they work so well in PV solar panels because they make good photovoltaic systems.

These materials being semiconductive means that they’re not good as insulators OR as standard conductors. In turn, this makes them good for dealing with electricity and semiconductors are used for many purposes besides solar energy. They are commonly used in transistors, meaning there’s likely semiconductive materials inside the device you’re using to read this!

Some examples of semi-conductive elements are;

antimony,
arsenic,
boron,
carbon,
germanium,
selenium,
silicon,
sulfur,
and tellurium.

Although PV solar panels are generally made up of crystalline silicon, or silicon blends.

What is the photovoltaic effect?

The photovoltaic effect occurs when a photovoltaic cell is exposed to enough sunlight. The term is used to describe the way electrical currents are produced by photovoltaic cells. Simply put, the photovoltaic effect is how solar panels work.

Photovoltaic cells are made up of two different types of semiconductors: p-type (positive) and n-type (negative). When you put these two types of semiconductors together you create something called a p-n junction, which forms an electrical field.

The reason an electrical field is formed by joining p-type and n-type semiconductors is due to the effect they have on different types of electrons. Electrons will naturally gravitate towards the positive p-type semiconductor due to their negative charge. In return, electron holes (sometimes just referred to as “holes”) will move towards the n-type semiconductor because they possess a positive charge.

Basically: the semiconductor’s electrical field makes negatively charged particles move one way and positively charged particles move the other way. So, how do solar panels work? Simply put, they utilise the effect of light on this photovoltaic field.

Photons are light particles composed of a collection of electromagnetic radiation working at different frequencies. The frequency of a light particle is dependent on how quickly it’s moving. The faster the movement, the higher the frequency, and in turn; the more energy for our PV solar panels to collect.

When ultraviolet rays (UV) fall on our semiconductive material energy from the photons then moves to electrons trapped in the p-n junction of the solar panels. This energy transfer causes the electrons within the solar panels to move to a higher state known as the “conduction band”.

What is the conduction band?

The conduction band is the name for a specific state electrons can enter. When electrons gain enough energy – in our case, from absorbing the energy stored in sunlight – they can move freely through materials regardless of their charge.

This is the desired effect for the electrons in our solar panels as it is the movement of these electrons which generates an electrical current within the solar cell.

Solar Panels Protective Layer

Solar cells are coated in a protective layer that – up to a certain point – shields them from the environment, for example excess heat and frost. They also have an anti-reflective layer as reflecting the light from the sun would sort of defeat the whole point of the panels.

Due to;

The anti-glare layer,
continued research into solar power,
And experimenting with various semiconductive materials.

Each new generation of solar cells is able to capture more energy from the sun than previous counterparts.

Contact Us

System Electrical Group has over twenty years in the electrical industry and is happy to work with you on your commercial project.

Please don’t hesitate to get in contact if you have any additional questions, or want to start the process of your commercial solar panel installation.