Sun Energy - Photovoltics and Photovoltaic Systems

Photovoltaic systems convert light energy into electricity.

photovoltaic modules
Grid-firing of 150-mm cells, a method used in manufacturing photovoltaic modules. DOE

Solar panels are devices that convert light into electricity. They are called solar after the sun or "Sol" because the sun is the most powerful source of the light to use. They are sometimes called photovoltaics which means "light-electricity". Solar cells or PV cells rely on the photovoltaic effect to absorb the energy of the sun and cause current to flow between two oppositely charge layers.


Photovoltaic (or PV) systems convert light energy into electricity.
The term "photo" is a stem from the Greek "phos," which means "light." "Volt" is named for Alessandro Volta (1745-1827), a pioneer in the study of electricity. Photovoltaics literally means light-electricity.

Most commonly known as "solar cells," PV systems are already an important part of our lives. The simplest systems power many of the small calculators and wrist watches we use every day. More complicated systems provide electricity for pumping water, powering communications equipment, and even lighting our homes and running our appliances. In a surprising number of cases, PV power is the cheapest form of electricity for performing these tasks.

History of Photovoltaic Cells

Photovoltaic cells convert light energy into electricity at the atomic level. French physicist Edmond Becquerel first described the photovoltaic effect in 1839, but it remained a curiosity of science for the next three quarters of a century.
At only nineteen, Becquerel found that certain materials would produce small amounts of electric current when exposed to light.

The effect was first studied in solids, such as selenium, by Heinrich Hertz in the 1870s. Soon afterward, selenium photovoltaic cells were converting light to electricity at one percent to two percent efficiency.

As a result, selenium was quickly adopted in the emerging field of photography for use in light-measuring devices.

Major steps toward commercializing photovoltaic cells began in the 1940s and early 1950s, when the Czochralski process was developed for producing highly pure crystalline silicon. In 1954, scientists at Bell Laboratories depended on the Czochralski process to develop a crystalline silicon photovoltaic cell, with an efficiency of six percent.