We know solar panels capture and convert the light of the sun into usable electrical energy. But does solar power work with artificial light?
Solar energy can only be made from a certain range of light wavelengths, which are found in both direct sunlight and artificial light. Other kinds of light that we can see can also charge solar panels.
If the light is strong enough, artificial lights can charge solar cells. However, the way solar cells work now, they cannot use artificial light to make enough electricity to be useful.
Technically, it is possible to charge solar cells when there is no sun, but solar cells don’t work well if charged by artificial light.
Besides, the whole idea of charging a solar cell with artificial light is a waste of energy.
Solar panels get some charge even on cloudy days.
Even though it will not be as strong as on bright days, the sun is still sending energy to Earth.
So, using an amorphous solar panel instead of the more common polycrystalline or monocrystalline panels is the best way to charge solar batteries or lights on cloudy days.
Amorphous panels are not as efficient as polycrystalline or monocrystalline panels, but they collect more light energy from cloudy skies.
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How Do Solar Panels Work?
When light hits a photovoltaic (PV) cell, also called a solar cell, the light can be reflected, absorbed, or just pass right through the cell.
The PV cell is made of a material called a semiconductor.
When the semiconductor is exposed to light, it takes in the light’s energy and sends it to particles in the material called electrons that are negatively charged.
Because of this extra energy, electrons can move through the material as an electrical current that can power your home.
The amount of energy that a solar cell can get from a light source shows how well it works. This depends on the properties of the light, its brightness, and the length of its wavelengths. Wavelengths that are longer have less energy than shorter wavelengths.
The so-called band gap of a PV semiconductor is a key property that determines which wavelengths of light it can absorb and turn into power.
There is only a small range of wavelengths that the cell can see. If the band gap of the semiconductor matches the length of the light waves that hit the PV cell, it can use the energy.
Can Artificial Lights Charge a Solar Cell Efficiently?
A standard silicon solar cell works with most of the sun’s visible light, about half of its infrared light, and some of its ultraviolet light (but not much of it, which makes UV light the least efficient in charging a solar gadget).
Solar cells can be made with multiple layers that mix silicon with impurities. Each layer has its response curve, which makes them work better. The top layer absorbs the shorter wavelengths, while the longer wavelengths reach the bottom layer. As a result, the conversion efficiency is much higher, and solar panels produce more energy.
Because artificial light sources like incandescent and fluorescent bulbs have a spectrum similar to the sun’s, they can charge solar cells and power small devices such as hand watches and calculators.
Artificial lights can never charge a solar cell as much as direct sunlight can for several reasons:
1. Conversion Loss
Artificial light must first turn electricity into the light for solar cells to absorb and turn back into electricity. Some of the energy is lost during this conversion process.
2. Spectral Intensity
The sun’s spectral radiance is always very strong and covers a wide range of light wavelengths, so solar cells can absorb light as efficiently as possible. Artificial lights have a weaker spectral irradiance that also changes quickly, for which they cannot absorb energy well.
3. Barriers to Light
Many artificial lights are not very bright and have barriers that cause some of the light they give off to be absorbed by glass or spread around.
If you are looking for ways to get the most out of your solar power when there’s little or no sunlight, get high-efficiency solar panels and a solar battery to store the electricity you make during the day so you can use it at night or on cloudy days.
Which Types of Artificial Lights Can Charge Solar Cells?
Incandescent Light
Solar cells react to incandescent light in a way that is similar to how they react to sunlight. This is because both sunlight and incandescent light bulbs give off light waves that solar cells can pick up and turn into energy.
Incandescent lights need to be bright enough, but if they are, their light wavelengths are similar enough to the sun’s Ultraviolet waves that solar cells can turn the energy into usable power.
Incandescent bulbs are not as good at charging solar cells because they need the power to make power, while solar charging only needs the sun’s energy, which is a renewable resource.
To charge a battery or other solar-powered item with an incandescent bulb, place the item about 20 inches from the light source and leave it there for as long as possible.
Since incandescent bulbs are not as strong as direct sunlight, they will probably take longer to charge than they would outside.
You can use any type of lightbulb that gives off light in the right range of light waves.
LED Lights
LED lights use visible light, long waves of infrared light, and ultraviolet light, which come from the sun.
But most light sources, such as LED, incandescent, halogen, and most household lights, do not give off much ultraviolet light.
The same idea is used here for incandescent light. LED light is a good choice if you want to use another source of electricity to make solar light.
LED is made to make a wide range of light wavelengths, like the Sun. These wavelengths include visible light, long infrared waves, and ultraviolet waves.
Each source of light, though, has its spectrum. The Sun gives off a lot of ultraviolet, but an incandescent light only gives off a small amount.
What Is Conversion Loss?
The conversion efficiency of a solar cell (photovoltaic (PV) cell), is the amount of solar energy a solar panel turns into electricity.
Improving conversion efficiency is one of the major goals of the research.
Not all the light that hits a photovoltaic cell turns into electricity. Most of it is lost.
Several things about how a solar cell is made can make it less efficient at turning the light it gets into energy. Having these things in mind when designing is the way to make things more efficient.
Wavelength
Light comprises photons, which are packets of energy with a wide range of energies and lengths of light.
The sun’s rays that reach the surface of the earth have wavelengths that range from ultraviolet to infrared. Some photons are reflected when light hits the surface of a solar cell, while others go right through.
The energy from some photons that are taken in is turned into heat.
The rest have the right amount of energy to separate electrons from their atomic bonds to make charge carriers and electric current.
Recombination
One way for an electric current to flow through a semiconductor is for a “charge carrier,” like a negatively charged electron, to move across the material. A hole represents the absence of an electron in a material, which is another type of charge carrier.
It acts as a positive charge carrier.
When an electron comes across a hole, the electron and the hole can join back together.
This cancels out their contributions to the electric current. A solar cell produces electricity when light-generated electrons and holes meet each other, combine, and send out a photon.
Indirect recombination is a process that happens when electrons or holes come across an impurity, a flaw in the crystal structure, or an interface that makes it easier for them to recombine and release their energy as heat.
Temperature
Most solar cells work best when the temperature is low.
With temperature increase, the properties of the semiconductor change.
The current goes up a bit, but the voltage goes down a lot more.
Extreme temperature rises can also damage the cell and other parts of the module, shortening their useful lives.
Since most of the light that hits solar cells is turned into heat, managing the heat is important for both efficiency and longevity.
Reflection
You can make a cell work better by reducing the amount of light that bounces off its surface.
For example, untreated silicon reflects over 30% of the light that hits it.
Coatings that do not reflect light and textured surfaces can help reduce reflection.
A cell that works well will look dark blue or black.
Is Dye-Sensitized Solar Cells Change Technology the Future of Solar?
Dye-sensitized solar cells (DSSCs) are a type of inexpensive solar (photovoltaic) cell that can turn visible light into electricity.
When these solar cells take in natural light, they act like photosynthesis.
The dye-sensitized solar cell can make electricity even when there is not much light.
Because of how such a cell is built and the different dyes used in the making, the cell is both colored and clear, like dyed transparent glass. So, DSSCs will surely have applications in architecture, interior decorations, electronic devices, and portable power systems.
The dye-sensitized solar cells are made of cheap parts and cost little to make. These solar cells are printable on any flexible surface.
Thin-film photovoltaic devices, which can be put on windows, skylights, and even the outside of a building, make the sun less of a problem.
Conventional solar panels, which are made of silicon cells, still have an advantage over this new solar technology, but they are not as flexible.
While silicon cells lose 20% of their energy efficiency at high temperatures, dye-sensitized solar cells work equally well at 149° F as they do at 77° F.
Final Thoughts
Remember that solar panels get sufficient sun to convert the light into usable energy even on cloudy days or in shade, although not as well as when exposed to direct sunlight.
Artificial light cannot match the power and brightness of real sun rays, at least not at the level needed to do a good job.
There is no good reason that makes sense to power solar cells with light from a lamp.
Compare the idea with using a candle to cook your food. Is it possible? Yes, it is. It takes time, but you will have your food prepared. But how many candles would you need to cook your meal?
Similarly, trying to charge a solar panel with artificial light is both a waste of time and energy.
