Solar cell

Sunlight can make power.

Special cells catch the light. They turn it into electricity. These cells are often made of silicon.

Many cells work together in a group. We call this group a solar panel.

A sheet of glass protects the cells. The glass lets light pass through.

Solar power can even move cars.

These are called solar cars. They use light to run motors. Some extra power goes into batteries.

Space tools use these cells too. Satellites use them for power. This helps them work for a long time. They can even use light in space.

A solar cell turns light into electricity. This happens through the photovoltaic effect. This is a way light makes power.

Most cells use a material called silicon. This makes up 95 percent of the market.

To work, a cell needs three steps. First, it must catch light. Next, it must separate tiny charges. Finally, it must move those charges into a circuit. Many cells join together to make a solar panel. A sheet of glass covers them. This glass protects the parts from the weather.

Solar power can also move cars. These are called solar cars. They use light to run motors. Any extra power goes into batteries.

In 1987, there was a big race in Australia. A car called the Sunraycer won the race. It went over 40 miles per hour.

Space tools use these cells too. The Vanguard 1 satellite used them in 1958. This helped the satellite work for a long time. Today, many satellites use solar arrays to get power.

A solar cell is a clever device that turns light directly into electricity. Scientists call this the photovoltaic effect. These cells are the building blocks for larger solar panels. Most solar cells today are made of crystalline silicon. This material makes up 95 percent of the whole market. Other cells use a material called cadmium telluride.

These devices can work under the bright sun or even artificial light. They can also be used to detect light or measure how intense it is.

How does a solar cell actually work? It happens in three main steps. First, the cell must absorb light. This absorption creates tiny particles called excitons. Next, the cell must separate opposite charges. This means it pulls positive and negative parts away from each other. Finally, the cell must move these charges into an external circuit. This flow of charges is what we call electricity.

People have been studying this for a long time. A French physicist named Edmond Becquerel first showed this effect in 1839. He was only 19 years old at the time! Later, in 1883, Charles Fritts built a cell using selenium and gold. It was only 1 percent efficient, which is very low. In 1905, Albert Einstein explained how light works in a famous paper. This work helped him win the Nobel Prize in 1921.

Solar cells are used in many amazing places. They can even power cars! These are often called solar cars. In 1987, there was a big race in the Australian outback. A vehicle called the Sunraycer won the race. It reached speeds of over 40 mph.

Solar cells are also vital in space. The Vanguard 1 satellite used them in 1958. This helped the satellite stay powered for a long time.

Today, we see solar technology everywhere. You might see solar panels on a house roof. Many satellites use large solar arrays to catch sunlight in orbit. Some of these arrays are even flexible and can roll up. This makes them easier to pack into a rocket. These tools help us use the sun's energy to power our world.

A solar cell, also known as a photovoltaic (PV) cell, is an electronic device that converts light energy directly into electricity. This conversion happens through a process called the photovoltaic effect. These cells serve as the fundamental building blocks for larger photovoltaic modules, which people commonly call solar panels. While they are most famous for generating power, they can also function as photodetectors. This means they can detect electromagnetic radiation near the visible light range or measure light intensity.

The mechanism of a PV cell relies on three essential stages to function. First, the device must absorb light. This absorption generates excitons, which are bound electron-hole pairs, or it creates unbound electron-hole pairs or plasmons. Second, the cell must achieve the separation of charge carriers. These carriers are the oppositely charged particles created by the light. Third, the cell must perform the separate extraction of these carriers into an external circuit. This flow of charges creates the electrical current we use.

Most modern solar cells are categorized by the materials they use. Approximately 95% of the commercial market uses crystalline silicon. The remaining market share is composed of cadmium telluride thin-film solar cells. A common single-junction silicon cell can produce a maximum open-circuit voltage of about 0.5 to 0.6 volts. There are also photoelectrolytic cells, or photoelectrochemical cells. These use light to excite electrons that are transported by a semiconductor. This process can actually use light to split water directly into hydrogen and oxygen for power generation.

The history of solar technology spans nearly two centuries of discovery. In 1839, a 19-year-old French physicist named Edmond Becquerel built the first photovoltaic cell. In 1873, Willoughby Smith described the effect of light on selenium. By 1883, Charles Fritts created a solid-state cell by coating selenium with gold, though it was only 1% efficient. A major breakthrough occurred in 1905 when Albert Einstein proposed a quantum theory of light. This explanation of the photoelectric effect earned him the Nobel Prize in Physics in 1921. In 1954, the first practical photovoltaic cell was demonstrated at Bell Laboratories by Calvin Souther Fuller, Daryl Chapin, and Gerald Pearson.

Solar cells have played a massive role in the history of space exploration. The Vanguard 1 satellite in 1958 was the first to use solar cells in space. This allowed the mission to last much longer than a battery-only system would. In 1959, the Explorer 6 satellite used large, wing-shaped arrays containing 9,600 Hoffman solar cells. By the 1960s, solar cells became the primary power source for most Earth-orbiting satellites. This was because they offered the best power-to-weight ratio for space travel. Modern spacecraft now use advanced III-V multijunction cells. These cells use different p–n junctions with varying bandgaps to capture a wider spectrum of solar energy.

Beyond space, solar cells have been applied to transportation and large-scale energy. Solar cars are electric vehicles that use solar panels to power electric motors. In 1987, the World Solar Challenge held a 3,000 km race across the Australian outback. General Motors won the race with their Sunraycer vehicle, which reached speeds over 40 mph.

On Earth, solar modules are often connected in series to increase voltage or in parallel to increase current. To prevent power loss from shade, modules use bypass diodes. These diodes allow current to skip over shaded or underperforming cells. This protection prevents damage from reverse bias applied by illuminated neighbors.

Today, the solar industry is a global system of interconnected technologies. Large arrays of modules create a solar array to produce direct current (DC). Most systems then use an inverter to convert this into alternating current (AC). The cost of these systems has changed significantly over time. In the United States, the cost per watt for utility-scale systems declined to $0.94 by 2020. This technology connects to many fields, from residential rooftop power to advanced satellite engineering. Whether they are flexible, rollable arrays in space or large silicon farms on Earth, solar cells continue to evolve.