What Is Solar Cell Also Called?

Solar cells, also known as photovoltaic (PV) cells, are devices that convert sunlight into electricity. They are made of semiconducting materials that absorb photons from sunlight and release electrons, generating an electric current. The generated electricity can be used to power homes, buildings, and devices or fed into the electricity grid.

The basic purpose of solar cells is to harness the abundant clean and renewable energy from the sun and convert it into useful electricity with zero emissions. This electricity can displace fossil fuels, reduce greenhouse gas emissions, and provide energy access. Solar cells have become a key technology in combating climate change and transitioning to sustainable energy.

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Other Names for Solar Cells

Solar cells are known by several other names, including:

Photovoltaic cells
PV cells
Solar photovoltaic cells

Photovoltaic modules
Solar modules
PV modules

The most common alternate name is photovoltaic cell, or PV cell for short. This name comes from the process solar cells use to convert sunlight into electricity – the photovoltaic effect.

History of Solar Cells

The concept of converting sunlight into electricity dates back to the 19th century. In 1839, French physicist Edmond Becquerel first discovered the photovoltaic effect while experimenting with metal electrodes in electrolyte solutions. He found that certain materials would produce small amounts of electric current when exposed to light.

In 1883, American inventor Charles Fritts created the first true solar cell by coating selenium with a thin layer of gold. While his solar cell was inefficient, it proved that electricity could be created solely from sunlight without any mechanical devices.

In the early 1900s, Albert Einstein helped explain the photoelectric effect, which aided the theoretical understanding of converting light into electricity. Incremental advances were made over the first half of the 20th century.

The first modern solar cell based on silicon technology was created in 1954 by researchers at Bell Laboratories. This paved the way for the rapid development and commercialization of photovoltaics. As manufacturing techniques improved and costs declined, solar cells found widespread practical use beginning in the 1990s.

Today, solar cells have become a mainstream renewable energy technology. Continued advancements in efficiency and lower costs are enabling more large-scale adoption of solar power around the world.

How Solar Cells Work

Solar cells, also known as photovoltaic (PV) cells, convert sunlight directly into electricity using the photoelectric effect. When sunlight hits the solar cell, photons with energy greater than the bandgap energy of the semiconductor material are absorbed. This photon absorption generates electron-hole pairs – the photo-generated electrons gain energy from the photons to jump from the valence band to the conduction band, creating mobile charge carriers. The built-in electric field of the PN junction separates the positive holes and negative electrons, creating a voltage difference. Metal contacts on the front and back allow the electrons to flow through an external circuit as electric current. This current generation continues as long as photons keep exciting electron-hole pairs in the semiconductor.

The key phenomena happening inside a solar cell are:

Photon absorption and electron-hole generation due to the photoelectric effect
Separation of charge carriers by the PN junction
Collection of electrons and holes by the front and back contacts

When sunlight shines on the solar cell, the absorbed photon energy frees electrons from the semiconductor’s crystal lattice structure, allowing them to flow through the external circuit. This photovoltaic effect generates usable electricity from sunlight without any moving parts or environmental impact.

Components

Solar cells are made up of several key components that enable them to convert sunlight into electricity. Here are the basic components of a solar cell:

Semiconductors

Solar cells are made from semiconductors such as silicon. Semiconductors have a unique ability to absorb photons from sunlight and release electrons. When sunlight hits the solar cell, the electrons move and generate an electric current.

Electric Field

The solar cell has an electric field that acts to force electrons freed by the photons to flow in a certain direction, creating electricity. The electric field is created by the interaction of negatively charged electrons and positively charged holes.

Anodes and Cathodes

The anode and cathode on the surface of the solar cell allow the current generated to flow in one direction and be utilized. The anode collects electrons while the cathode collects holes. When connected, they allow electricity to flow.

Anti-Reflective Coating

Solar cells have an anti-reflective coating that helps trap and absorb more sunlight. This coating reduces reflected sunlight and maximizes the amount of light absorbed to create more electricity.

Types

There are several different types of solar cells, classified mainly by the photovoltaic material used in their manufacture.

Silicon Cells

The most common type of solar cell is made from crystalline silicon. This material is cut into wafers and treated to form an electric field that generates electricity when exposed to sunlight. Silicon cells come in three main types:

Monocrystalline silicon – Made from single crystals of silicon and tend to be the most efficient.

Polycrystalline silicon – Made from many crystals of silicon fused together and are cheaper but less efficient.
Amorphous silicon – Made by depositing silicon layers on a substrate. These flexible cells are even cheaper but much less efficient.

Thin-Film Cells

Thin-film solar cells are made by depositing extremely thin layers of photosensitive materials on a substrate like glass or plastic. Types of thin-film cells include:

Cadmium telluride (CdTe)
Copper indium gallium selenide (CIGS)
Gallium arsenide (GaAs)

Thin-film cells are inexpensive to manufacture but usually have lower efficiency ratings.

Organic Photovoltaic Cells

Organic PV cells use organic electronics, hydrocarbon molecules and polymers as the photoactive components. They can be made into thin, flexible cells via solution processing. Organic cells are affordable but less efficient than inorganic cells.

Efficiency

The efficiency of a solar cell refers to the percentage of sunlight energy that is converted into electricity. Simply put, efficiency measures how much electrical power a solar cell produces relative to the amount of sunlight shining on it. A more efficient solar cell is able to generate more electricity from the same amount of sunlight.

Most mass-market solar cells today have efficiencies in the range of 15% to 22%. However, researchers around the world are working on improving solar cell efficiency in order to lower the overall costs of solar power. Some experimental high-efficiency solar cells in laboratory settings have exceeded 45% efficiency.

There are a few key ways that researchers are trying to boost the efficiency of solar cells:

Using advanced semiconductor materials like gallium arsenide that have properties better suited for capturing photons.

Stacking multiple thin layers of materials to better absorb different wavelengths of light.
Reducing defects and impurities in the semiconductor manufacturing process.
Trapping light within the cell using nanoscale textures and optical coatings.

Increasing the percentage of a solar cell that is electrically active as opposed to inactive structural components.

Higher solar cell efficiency means that less surface area is needed to generate the same amount of electricity. This in turn reduces the manufacturing and installation costs per watt of solar power capacity. Efficiency gains remain a key focus of research as solar power competes with conventional energy sources.

Applications

Solar cells have a wide variety of applications in today’s world. Here are some of the main ways that solar cells are being utilized:

Solar Power Plants

One of the most common applications is in large-scale solar power plants. These plants contain thousands of solar panels and convert sunlight into electricity that can be fed into the grid to supply homes and businesses.

Residential Rooftop Solar

An increasingly popular application is rooftop solar panels on people’s homes. This allows homeowners to generate their own electricity and reduce reliance on the grid. Many homeowners with solar panels even produce excess energy that gets sold back to utility companies.

Off-Grid Electricity

Solar cells are very useful for providing electricity in remote areas without connections to utility grids. Individual solar panels can provide power for things like road signs, parks, communications equipment, and more.

Spacecraft and Satellites

Solar energy is the most readily available power source for spacecraft and satellites. Solar cells are a vital component of power systems for space vehicles and orbiting satellites.

Consumer Electronics

Small solar cells are implemented in a range of consumer devices such as calculators, watches, and chargers to provide power in the absence of batteries.

Solar cell technology will continue finding new applications as efficiency improves and costs decrease over time.

Future Outlook

The future looks bright for solar cell technology. Researchers are continuously working to improve solar cell efficiency and find new applications. Some key areas of progress include:

Improved materials – New materials like perovskites and organic PV cells are enabling higher efficiency conversion of sunlight to electricity. Continued research into novel materials will help push efficiency limits even further.

Manufacturing improvements – New manufacturing techniques like thin-film and multi-junction solar cells can increase efficiency. Manufacturing innovations will help drive down costs as well.

New applications – Solar cells have huge potential to integrate into building materials, vehicles, gadgets and more. Advances in flexible solar cells specifically open up many new possibilities. We will see solar cells become ubiquitous in consumer products and smart cities.

Storage integration – Integrating energy storage solutions with solar technology will enable wider adoption. This will allow solar energy to be used anytime, not just when the sun is shining.

Emerging markets – Declining costs will enable solar deployment in new markets across the developing world. This will bring clean electricity to millions of new households and businesses.

With continued research and investment, solar cells have an exciting future ahead as a mainstream energy source worldwide.

Conclusion

In conclusion, solar cells, also known as photovoltaic cells, are an important renewable energy technology that converts sunlight into electricity. We discussed how solar cells work using the photovoltaic effect and their key components like semiconductors and electrodes. There are many types of solar cells, with varying levels of efficiency and applications. From powering small devices like calculators to large solar farms, solar cell usage is growing rapidly. With solar energy playing an increasingly vital role in powering our world in a clean and sustainable way, continued research and development is poised to further improve the efficiency and expand the versatility of solar cells going forward.