Can You Charge a Solar Panel with UV Light?

Last Updated on July 12th, 2023

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The demand for renewable energy technologies is constantly increasing, and solar power is just one answer to the problems of energy generation for a growing population and climate change.

Despite deriving their name from our closest star (the Sun), solar panels do not strictly need sunlight to charge or function in general. However, using artificial light to charge a solar panel is not as easy or as useful as it may seem.

Read on to learn more about solar panels, their ability to charge, and why artificial light cannot truly replace sunlight.

Solar panels on roof at night - Can You Charge a Solar Panel with UV Light

Can You Charge a Solar Panel with a UV Light?

To answer the question of whether a solar panel can be charged with ultraviolet (UV) light, we first have to understand some basics of how solar panels work and physics in general.

The photovoltaic (PV) cell is the individual unit of a solar panel and is typically made up of a silicon-based semiconductor that absorbs the energy of light that strikes and passes through the semiconductor. 

The energy of the light is passed on to electrons in the semiconductor, which flows as a current, which is how electricity is generated.

The spectrum of electromagnetic radiation includes wavelengths we associate with “light,” which most often include infrared, visible, and ultraviolet light. 

Infrared has a longer wavelength with lower energy, while ultraviolet light has a shorter wavelength and much higher energy, with visible light lying somewhere between the two.

A PV cell features a “band gap,” which is the wavelengths of light that it absorbs. Because solar panels are specifically designed to absorb the visible wavelengths of sunlight, UV wavelengths are not often captured.

So, while it is technically possible to charge a solar panel with an artificial UV light, there wouldn’t be much point because very little of the energy would be captured.


What Kind of UV Light Can Charge a Solar Panel?

There is only a very small portion of UV light that will be able to charge today’s version of solar panels, even if they are high-efficiency solar panels.

This portion of UV light is known as ultraviolet A or UVA radiation, and even within the small range of UVA wavelengths, only a limited subset of wavelengths are capable of charging a solar panel because they happen to overlap with one extreme of the visible light spectrum.

Although UV wavelengths seem to be the answer to more efficient solar panels because they are naturally higher in energy, they only make up 3% of all sunlight, even when the Sun is at its highest in the sky. 

This means it doesn’t make sense when we could easily capture the other 97%.

A backlight with no filter is pretty much your only option to charge a solar panel with artificial light because it generates the correct range of wavelengths.


Which Types of UV Lights Will Not Charge a Solar Panel?

UV wavelengths are on a spectrum between 100-400 nm in length, largely grouped into three different categories based on said wavelengths.

Ultraviolet C or UVC covers wavelengths between 100-280 nm inclusive, ultraviolet B, also known as UVB, includes wavelengths from 280 nm to 315 nm, and modern solar panels, UVA can absorb the part of the spectrum we know, is left with wavelengths of 315-400 nm.

What this means is that any natural or artificial light sources that emit a wavelength or set of wavelengths from UVB or UVC are all but useless when it comes to charging a solar panel.


What Kind of UV Light is the Fastest For Charging a Solar Panel?

We have established that UVA wavelengths are the best for charging a solar panel, but not all of the UVA wavelengths are able to charge a solar panel. 

Only the UVA wavelengths between 400 nm and 380 nm, which are at the very highest energy part of the visible light spectrum, are able to be absorbed and converted into electricity with conventional solar panels.

Unless you get into the specifics of your solar panel’s band gap, there isn’t any one wavelength that will perform better than the others. 

Of course, each wavelength will charge just as quickly as the others, but if there were a difference in charge times, it would be immeasurable without highly precise instruments.


Where Can You Buy the Best UV Light Source for Solar Panels?

If you’re in the market for a UV light source to power small solar panels because you can’t use the free light from the Sun for whatever reason, more likely than not, you’re going to have to turn to the internet and online shopping.

On Amazon, you can search for UV lights with specific wavelengths so that you find the right ones that work for you. You can even find ones that use light-emitting diodes (LEDs) for greater lumens at a reduced electricity consumption rate.

Walmart and Home Depot are other examples of locations that could have a backlight you need to charge a solar panel, but you may want to check by calling or looking it up online before going in to make a purchase.

One of the best UV lights for charging a solar panel would be Wildfire Lighting’s BlueBar, an LED light bar that produces wavelengths between 385 nm and 400 nm, all of which can be absorbed by solar panels.


Final Thoughts on Charging a Solar Panel with a UV Light

While it is certainly possible to charge a solar panel using artificial light sources. 

Even with UV light sources, it is not a recommended practice because there is a huge loss of energy between all the conversions of electricity to light and back, which ends up costing you on your electricity bill.

If you are determined to charge a solar panel with UV light, make sure you get the right wavelengths out of your product; otherwise, the panel won’t charge no matter how long you shine the light at it.


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