In 1839, the ability of some materials to create an electrical charge from light exposure was first observed by Alexandre-Edmond Becquerel. Though the premiere solar panels were too inefficient for even simple electric devices they were used as an instrument to measure light.
The term photovoltaic comes from the Greek φώς: phos, which means "light" and voltaic, which comes from the field of electricity, in honor of the Italian physicist Alejandro Volta, (who also provides the term volt to the unit of measurement of the difference of potential in the International System of measurements). The term photovoltaic began to be used in England from the year 1849.
The observation by Becquerel was not replicated again until 1873, when Willoughby Smith discovered that the charge could be caused by light hitting selenium. After this discovery, William Grylls Adams and Richard Evans Day published "The action of light on selenium" in 1876, describing the experiment they used to replicate Smith's results
In 1881, almost 50 years after the photovoltaic effect’s discovery, Charles Fritts created the first commercial solar panel, a working selenium solar cell, which was reported by Fritts as "continuous, constant and of considerable force not only by exposure to sunlight but also to dim, diffused daylight." However, these solar panels were very inefficient, especially compared to coal-fired power plants.
In 1905 Albert Einstein publishes his theory on the photoelectric effect which will bring him the Nobel Prize in Physics in 1921.
In 1939, Russell Ohl created the solar cell design that is used in many modern solar panels. He patented his design in 1941.
In 1954, this design was first used by Bell Labs to create the first commercially viable silicon solar cell.
In 1957, Mohamed M. Atalla developed the process of silicon surface passivation by thermal oxidation at Bell Labs.The surface passivation process has since been critical to solar cell efficiency.
These advances contributed to the manufacture of the first commercial solar cell with a solar energy conversion of approximately 6%. The USSR launched its first space satellite in 1957, and the US a few months later. Solar cells created by Peter Iles in an effort spearheaded by the Hoffman Electronics company were used in the design of this.
The first spacecraft to use solar panels was the North American Vanguard 1 satellite, launched in March 1958. This milestone generated great interest in the production and launch of geostationary satellites for the development of communications, in which the energy would come from a device for capturing sunlight. It was a crucial development that spurred research by some governments and prompted the improvement of solar panels.
In 1963 Japan's Sharp produces the first commercial photovoltaic modules.
In 1970 the first highly efficient gallium arsenide (GaAs) heterostructure solar cell was developed in the former USSR by Zhorés Alfiórov and his research team.
The production of equipment for the chemical deposition of metals by organic vapors or MOCVD (Metal Organic Chemical Vapor Deposition), was not developed until the 1980s, limiting the capacity of companies in the manufacture of gallium arsenide solar cells. The first company to manufacture solar panels in industrial quantities, from simple GaAs junctions, with an AM0 (Air Mass Zero) efficiency of 17% was the North American ASEC (Applied Solar Energy Corporation). The dual cell connection occurred in industrial quantities by ASEC in 1989, accidentally, as a consequence of a change from GaAs on GaAs substrates to GaAs on germanium substrates.
The accidental doping of germanium (Ge) with GaAs as a buffer layer created open voltage circuits, demonstrating the potential of using germanium substrates like other cells. A single junction cell of GaAs reached 19% AM0 efficiency in 1993. ASEC developed the first double junction cell for spacecraft used in the US, with an efficiency of approximately 20%.
These cells do not use germanium as a second cell, but use a GaAs-based cell with different types of doping. Exceptionally, GaAs double junction cells can produce AM0 efficiencies of the order of 22%. Triple junctions start with efficiencies of the order of 24% in 2000, 26% in 2002, 28% in 2005, and have typically reached 30% in 2007. In 2007, two North American companies, Emcore Photovoltaics and Spectrolab, produced 95% of solar cells 28% efficiency.
