Solar Cell And Solar Panel History
Using the sun as a source of energy isn’t a new concept. Our ancestors used it to start fires, to light torches for religious rites, and to heat private and public buildings. When Swiss scientist Horace de Saussere debuted his solar oven in 1767, presenting a device that trapped the sun’s heat through glass, he set a precedent for continued innovation.
By the 1830s, French physicist Edmond Becquerel documented the photovoltaic effect - the creation of voltage from light or radiant energy exposure. Within decades, his countryman Augustin Mouchot registered the first patent for solar-powered engines.
In the United States, Charles Fritts developed the solar cell in 1883, building on the observations of British scientists William Grylls Adams and Richard Evans Day. Fritts used selenium and gold to create a current, “that is continuous, constant, and of considerable force[,]...not only by exposure to sunlight, but also to dim diffused daylight, and even to lamplight.” German scientist Werner von Siemens used Fritt’s panel as his guide, declaring it to be, “the first time the direct conversion of energy of light into electrical energy” had been achieved.
Through the late 19th and entire 20th century, solar panel design continued to develop, incorporating new materials and processes. Noted scientists George Minchin and Albert Einstein contributed to the growing scholarship and practical experiments involving solar panels, adding essential understanding to the power of the sun’s rays.
Einstein, in line with Minchin’s earlier speculation about a surface’s ability to serve as “a transformer of the energy it receives from the sun,” proposed the existence of “quanta” in 1905. Einstein’s quantum theory of light allowed scientists to better understand how quanta, or photons, carried energy and reacted to various materials.
Einstein’s ideas prompted additional research and, some 16 years later, Einstein received the Nobel Prize in physics for describing the Law of Photoelectric Effect. The Law of Photoelectric Effect reinforced the concept of light wave-particle duality, and described how energy from light photons - or quanta - interact with electrons (negatively charged subatomic particles). Essentially, photon energy from light could dislodge electrons from a material, resulting in an exchange of energy to set the electron free from a surface. The remaining energy in the dislodged electron then bonded with the photon, resulting in a negative charge called a photoelectron.
Throughout the 1920s and 1930s, scientists articulated the photoelectric effect and the implications for photoelectrons with greater clarity. Similarly, solar researchers began to experiment with light on a variety of substances, namely silicon. Physicists, engineers, and scientists, notably Russell Ohl, explored the possibilities of silicon. In 1941, while studying the applications of silicon to radio technology, Ohl discovered the semiconductor potential of the element.
By running a light over a broken silicon crystal, Ohl demonstrated the p-type and n-type semiconductor materials in silicon and how, when they interfaced, they produced energy. Ohl’s employer, Bell Telephone Laboratories, led to further research in solar cell technology. This work culminated in the first practical solar cell, Bell Solar Battery, presented by engineer Daryl Chapin, physicist Gerald Pearson, and chemist Calvin Fuller in 1954.
The solar cell contained all of the necessary elements to convert sunlight into energy. Later, cells would be connected to circuits and sealed to create solar modules. This, in turn, was wired to a solar panel, designed to collect and direct electricity outward to the desired location.
Solar cell technology proliferated through the 1950s and 1960s, largely finding use in telecommunications. In The United States, Japan, and the Soviet Union, scientists experimented with new processes and applications for solar cells, powering satellites and wristwatches alike. Solar cells ranged in efficiency, initially hitting about 4% with the Bell Solar Battery and later reaching 14% in designs by Hoffman Electronics.
After Dr. Elliot Berman introduced a cheaper solar panel to market during the 1970s, one that reduced the price per watt from $100 to $20, solar energy was integrated into industrial and infrastructural settings alike. As power sources for warning lights, railroad crossings, lighthouses, and comparable devices, solar panels could also be used in areas far removed from established power grids.
By the 1970s, solar energy had been integrated into the roof at the Solar One building on the University of Delaware campus. While public use remained relatively limited, the energy crisis that plagued the United States during the 1970s prompted Congress to push for research and development of solar energy technologies.
Meanwhile, the solar cell industry produced increasingly efficient and powerful solar technologies. In 1982, Japan-based manufacturer, Kyocera, rolled out multicrystalline silicon (polysilicon) solar cells, using a casting method which would ultimately become standard in the solar panel industry.
Interest in solar energy stalled in the 1980s when energy prices again went down, but the technology itself continued to develop. Photochemical and photoelectrochemical cells - variations of basic cells that used dyes, metals, and the like to influence conduction and light sensitivity - resulted in an influx of solar panels in distribution. In 1992, solar cells with 20% efficiency were patented and, by the end of the 1990s, the “photovoltaic capacity reache[d] 1000 megawatts” worldwide.