The History Highlight of Solar Sells (Photovoltaic Cells)

1839 – The photovoltaic effect was discovered by Alexandre-Edmond Becquerel, who was a French physicist. This was “the beginning” of the solar cell technology. Becquerel's experiment was done by illuminating two electrodes with different types of light. The electrodes were coated by light sensitive materials, AgCl or AgBr, and carried out in a black box surrounded by an acid solution. The electricity increased when the light intensity increased.

1873 – The photo conductivity of an element, selenium, was discovered by Willoughby Smith, who was an English electrical engineer.

1876 – Selenium produces electrical current when it is exposed to sun light. William Grylls Adams and Richard Evans Day proved that it is possible to convert solar energy into electricity directly, without any moving parts or heat. The solar cell was very inefficient, and it couldn't be used to run any electrical equipment.

1883 – A description of the first solar cells made from selenium wafer were made by Charles Fritts.

1894 – Charles Fritts constructed what was probably the first true solar cell. He coated a semiconductor material (selenium) with an extremely thin layer of gold. The efficiency were only about 1%, so it couldn't be used as energy supply, but were later used as light sensors.

1904 – A German physicist, Wilhelm Ludwig Franz Hallwachs, discovered that a combination of copper and cuprous oxide was photosensitive.

1905 – Albert Einstein published his paper about the photoelectric effect. There he claimed that light consists of “packets” or quanta of energy, which we now call photons. This energy varies only with its frequency (electromagnetic waves, or the “color of the light”). This theory was very simple, but revolutionary, and it explained very well the absorption of the photons regarding to the frequency of the light.

1914 – Goldman and Brodsky noted that it existed a barrier layer in photovoltaic devices.

1916 – Robert Andrews Millikan provided experimental proof of the photoelectric effect. He was an American experimental physicist who later won the Nobel Prize for his work on the photoelectric effect and for his measurement of the charge of the electron.

1918 – Jan Czochralski, a Polish chemist, developed a way to grow single-crystal silicon. This increased the efficiency of the silicon-based cells considerably.

1923 – Albert Einstein received the Nobel Prize for his theories explaining the photoelectric effect, which he published 18 years earlier.

1930s – Walter Schottky, Neville Mott and some others developed a theory of metal-semiconductor barrier layers.

1932 – Audobert and Stora discover the photovoltaic effect in cadmium sulfide (CdS).

1950s – Bell Labs produce solar cells for space activities.

1951 – A grown p-n junction enabled the production of a single-crystal cell of germanium.

1953 – Dr. Dan Trivich of Wayne State University makes the first theoretical calculations of the efficiencies of various materials of different band-gap widths based on the spectrum of the sun

1954 – Three researchers,Gerald Pearson, Daryl Chapin and Calvin Fuller, at Bell Laboratories discovered a silicon solar cell, which was the first material to directly convert enough sunlight into electricity to run electrical devices. The efficiency of the silicon solar cell, which Bell Labs produced, were 4%, which later increased to 11%. The cells were made by hand and cost $1000 per watt.

1954 – A cadmium sulphide p-n junction was produced with an efficiency of 6%

1958 – Hoffman Electronics achieved 9% efficient PV cells.

1958 – The first PV-powered satellite, Vanguard I, was launched. The solar panel had an area of 100cm² and delivered an effect of approximately 0.1W. The satellite power system operated for 8 years, and is the world's oldest satellite still in orbit (2007).

1958 – Ted Mandelkorn of U.S. Signal Corps Laboratories fabricates n-on-p (negative layer on positive layer) silicon photovoltaic cells,

1959 – Hoffman Electronics achieved 10% efficient commercially available PV cells and demonstrated the use of a grid contact to significantly reduce series resistance.

1959 – Explorer-6 was launched with a PV array of 9600 cells, each only 1 cm x 2 cm.

1960 – Hoffman Electronics achieved 14% efficient PV cells.

1962 – The Telstar communications satellite, launched by Bell Labs, is initial powered(14W) by solar cells.

1963 – A Japanese electronic manufacturer, Sharp Corporation, produces a viable photovoltaic module of silicon solar cells.

1970 – First highly effective GaAs heterostructure solar cells are created by Zhores Alferov (a Russian physicist) and his team in the USSR.

1972 – The Institute of Energy Conversion is established at the University of Delaware to perform research and development on thin-film photovoltaic and solar thermal systems, becoming the world’s first laboratory dedicated to photovoltaic research and development.

1976 – David Carlson and Christopher Wronski of RCA Laboratories produced the first amorphous silicon photovoltaic cells, which could be less expensive to manufacture than crystalline silicon devices. The efficiency was of 1.1%.

1980 – At the University of Delaware, the first thin-film solar cell exceeds 10% efficiency. It's made of copper sulfide(Cu2S) and cadmium sulfide(CdS).

1981 – Paul MacCready builds the first solar-powered aircraft, the Solar Challenger, and flies it from France to England across the English Channel. The aircraft had over 16,000 solar cells mounted on its wings, which produced a power of 3kW.

1982 – Hans Tholstrup, an Australian, drives the first solar-powered car, the Quiet Achiever, 4,000km between Sydney and Perth in 20 days. That was 10 days faster than the first gasoline-powered car to do so. The maximum speed was 72 km/h, and the average speed was 24 km/h.

1984 – The IEEE Morris N. Liebmann Memorial Award was presented to Drs. David E. Carlson and Christopher R. Wronski at the 17th Photovoltaic Specialists Conference, "for crucial contributions to the use of amorphous silicon in low-cost, high-performance photovoltaic solar cells."

1985 – The University of South Wales breaks the 20% efficiency barrier for silicon solar cells under one sun conditions.

1989 – Reflective solar concentrators are first used with solar cells.

1991 – Efficient Photoelectrochemical cells (PEC) are developed. Each cell consists of a semiconducting photoanode and a metal cathode immersed in an electrolyte. The Dye-sensitized solar cell (DSC), also called Grätzel cells, is invented. It was a new class of low-class DSC.

1992 – University of South Florida develops a 15.9% efficient thin-film photovoltaic cell made of cadmium telluride, breaking the 15% barrier for the first time for this technology.

1994 – The National Renewable Energy Laboratory develops a solar cell, made from gallium indium phosphide and gallium arsenide, that becomes the first one to exceed 30% conversion efficiency.

1996 – Renewable Energy Corporation(REC), a Norwegian solar energy company established.

1996 – EPFL, the Swiss Federal Institute of Technology in Lausanne, achieves 11% efficiency with the DSCs.

1999 – Spectrolab, Inc. and the National Renewable Energy Laboratory develops a photovoltaic solar cell that converts 32.3 percent of the sunlight that hits it into electricity. The high conversion efficiency was achieved by combining three layers of photovoltaic materials into a single solar cell. The cell performed most efficiently when it received sunlight concentrated to 50 times normal. To use such cells in practical applications, the cell is mounted in a device that uses lenses or mirrors to concentrate sunlight onto the cell. Such “concentrator” systems are mounted on tracking systems that keep them pointed toward the sun.

1999 – The National Renewable Energy Laboratory achieves a new efficiency record for thin-film photovoltaic solar cells. The new measurement is of 18.8 percent efficiency.

2000 – Two new thin-film solar modules, developed by BP Solarex, break previous performance records. The company’s 0.5-square-meter module achieves 10.8 % conversion efficiency—the highest in the world for thin-film modules of its kind. And its 0.9-square-meter module achieved 10.6% conversion efficiency and a power output of 91.5 watts — the highest power output for any thin-film module in the world.

2001 – TerraSun LLC developes a methode of using holographic films to concentrate sunlight onto a solar cell

2003 – REC Solar started production.

2007 – The university of Delaware achieve a 42.8% efficiency solar cell technology.