Today's photovoltaic systems are used to generate electricity to pump water, light up the night, activate switches, charge batteries, supply power to the utility grid, and much more.
Nineteen-year-old Edmund Becquerel, a French experimental physicist, discovered the photovoltaic effect while experimenting with an electrolytic cell made up of two metal electrodes.
1873: Willoughby Smith discovered the photoconductivity of selenium.
Adams and Day observed the photovoltaic effect in solid selenium.
Charles Fritts, an American inventor, described the first solar cells made from selenium wafers.
Heinrich Hertz discovered that ultraviolet light altered the lowest voltage capable of causing a spark to jump between two metal electrodes.
Hallwachs discovered that a combination of copper and cuprous oxide was photosensitive. Einstein published his paper on the photoelectric effect.
The existence of a barrier layer in PV devices was reported.
Millikan provided experimental proof of the photoelectric effect.
Polish scientist Czochralski developed a way to grow single-crystal silicon.
1923: Albert Einstein
received the Nobel Prize for his theories explaining the photoelectric effect.
A grown p-n junction enabled the production of a single-crystal cell of germanium.
The PV effect in Cd was reported; primary work was performed by Rappaport, Loferski and Jenny at RCA. Bell Labs researchers Pearson, Chapin, and Fuller reported their discovery of 4.5% efficient silicon solar cells; this was raised to 6% only a few months later (by a work team including Mort Prince). Chapin, Fuller, Pearson (AT&T) submitted their results to the Journal of Applied Physics. AT&T demonstrated solar cells in Murray Hill, New Jersey, then at the National Academy of Science Meeting in Washington, DC.
Western Electric began to sell commercial licenses for silicon PV technologies; early successful products included PV-powered dollar bill changers and devices that decoded computer punch cards and tape. Bell System's demonstration of the type P rural carrier system began in Americus, Georgia. Hoffman Electronics's Semiconductor Division announced a commercial PV product at 2% efficiency; priced at $25/cell and at 14 mW each, the cost of energy was $1500/W.
Bell System's demonstration of the type P rural carrier system was terminated after five months.
Hoffman Electronics achieved 8% efficient cells. "Solar Energy Converting Apparatus," patent #2,780,765, was issued to Chapin, Fuller, and Pearson, AT&T.
Hoffman Electronics achieved 9% efficient PV cells. Vanguard I, the first PV-powered satellite, was launched in cooperation with the U.S. Signal Corp. The satellite power system operated for 8 years.
Hoffman Electronics achieved 10% efficient, commercially available PV cells and demonstrated the use of a grid contact to significantly reduce series resistance. Explorer-6 was launched with a PV array of 9600 cells, each only 1 cm x 2 cm.
Hoffman Electronics achieved 14% efficient PV cells.