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Whether you want to reduce your carbon footprint or save electricity bills, using solar energy is a good choice. Solar cells convert light and other forms of electromagnetic radiation into electrical energy. But when the sun goes down? Can artificial light sources charge solar cells? In this article, we will answer this question and provide some insights on how solar panels capture light.

This may be surprising, but technically speaking, yes. Solar panels can be charged with other forms of visible light besides sunlight. If the light is strong enough, you can use artificial lights such as incandescent fluorescent bulbs to charge the solar cells.

What light can be converted into solar energy depends on a certain range of light wavelengths, which are found in direct sunlight and artificial light. So yes, it is technically possible to charge solar cells without sunlight.

However, (I think you suspect this is coming), current solar cell technology cannot effectively convert artificial light into any useful electricity. To explain why, let's look at how solar panels capture light.

When light shines on a photovoltaic (PV) cell (also called a solar cell), the light may be reflected, absorbed, or pass directly through the cell.

PV cells are composed of semiconductor materials. When a semiconductor is exposed to light, it absorbs the energy of the light and transfers it to negatively charged particles in materials called electrons. This extra energy allows electrons to flow through the material as current. This current is drawn through conductive metal contacts (grid-like wires on solar cells), which can then be used to power your home.

The efficiency of a solar cell depends on the energy it can extract from the light source. This depends largely on the characteristics of the light, such as its intensity and wavelength. The longer the wavelength, the less energy, and the shorter the wavelength, the more energy.

The "band gap" of PV semiconductors is a key feature, which determines which wavelengths of light it can absorb and convert it into electrical energy. This will translate into a limited range of wavelengths, and cells will ignore those longer and shorter wavelengths. If the band gap of the semiconductor matches the wavelength of the light irradiated on the PV cell, it can effectively use the available energy.

Solar cells are specifically designed to absorb sunlight. A standard silicon solar cell responds to most of the visible part of the solar spectrum, about half of infrared light, and part of ultraviolet light (but not a lot, making ultraviolet light the least efficient light for charging). Solar light strip).  

In order to improve the efficiency of solar cells, there are multilayer designs that mix silicon with impurities, each with its own response curve. The top layer absorbs shorter wavelengths, and the bottom layer converts longer wavelengths. The result is significantly better conversion efficiency and better energy output.

Because artificial light sources such as incandescent and fluorescent lamps mimic the sun's spectrum, they can charge solar batteries to a certain extent, and can even power small devices such as calculators and watches. However, artificial light can never charge solar cells as efficiently as direct sunlight. This is due to a variety of factors:

Loss conversion: Artificial light must first convert electricity to light so that solar cells can absorb and convert back to electrical energy. During this conversion process, some energy is lost. This means that the energy generated by this method will always be less than the original energy used. 

Spectral intensity: The sun's spectral radiation intensity is extremely strong and constant, covering a wide range of light wavelengths, which can maximize the light absorption efficiency of solar cells. Artificial light not only has a weaker spectral irradiance than sunlight, but they also experience sharp fluctuations in spectral irradiance, which reduces their overall energy absorption.

Light barriers: Artificial lights usually contain barriers such as bulbs and ballasts, which can adjust their intensity and cause some of the light they emit to be absorbed by the glass or diffuse into the room.

In short, there is no really effective or logical reason to try to power solar cells with artificial light.

No artificial light can imitate the intensity and brightness of real sun rays, and of course it cannot reach the level required for effective execution. Just like you don't bother to use candles to cook food (unless you are eating hot pot), trying to charge solar panels with artificial light is a waste of time and energy.

If you are looking for ways to maximize solar power generation and consumption when there is limited or no sunlight, then it is worth considering using high-efficiency solar panels and solar cells to store solar power for use at night or on cloudy days.

Energy Matters has helped more than 30,000 Australians transition to clean energy. We can guide you in choosing solar and/or battery storage solutions that suit your lifestyle and budget. Receive up to 3 free quotes from our network of trusted and accredited solar installers. It's fast, free, and eliminates the hassle of shopping around.

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