Solar cells that can convert sunlight into electricity began to appear more than a hundred years ago, but early solar cells were too low, so they were not much use. In 1954 April, the United States Bell Labs researchers demonstrated the first practical silicon solar cells.
The story of the solar cell is to be traced back to the observation of the paleo-vodka effect in early 1839, the son of the French physicist Antoine Cesar Becquerel, the physicist Henri Becquerel, Alexandre Edmond Becquerel, who was the father of Alexandre Edmond Becquerel at the time of the Nobel Prize in Physics in 1903, made a study of metal electrodes in an electrolytic solution and found that if the metal was exposed to the sun, it would produce a small current He can not explain this effect.
A few decades later, in 1873, British engineer Smith (WilloughbySmith) discovered the photoconductivity of selenium when testing the material of the cable in the water. In 1883, American inventor Fletz (CharlesFritts) made the first solar cell with selenium. Although Fritz expects his solar cell to compete with Edison's thermal power plant, it is not practical for solar cells to convert sunlight into electricity at less than 1 percent. The study of the photodegradation of selenium lasted for several decades, during which several practical applications were found, but it was not widely used.
The next major advance in solar cell technology was developed in 1940 by a researcher at the Bell Labs semiconductor researcher, Orr (Russell Shoemaker Ohl). Orr had been studying silicon samples, one of which had a crack in the middle. He noticed that when the particular sample was exposed to the sun, the current would pass. The crack may be formed when the sample is made, and it is actually a dividing line with different levels of impurities, so that one side of the fracture exhibits a positive doping and the other side exhibits a negative doping, that is, Or has inadvertently made a pn junction, Is the basic principle of solar cells, excessive positive charge on the side of the pn junction, while the excess negative charge is gathered on the other side, causing the electric field. When the solar cell connected to the circuit, the photon into the battery will play electronic look, start the current. Orr will apply for a patent for his solar cell, which is about 1% efficient.
The first practical silicon solar cells in 13 years later, by a group of Bell Labs scientists together to develop.
In 1953, Daryl Chapin, an engineer at the Bell Labs who studied magnetic materials, was trying to develop new power sources for remote wet areas, due to the disappearance of dry battery power. Qiao Bin studied several alternative energy sources, and finally chose solar energy as one of the most promising sources of energy. He tried selenium solar cells, but found it inefficient.
At the same time, chemists Calvin Fuller and physicist Gerald Pearson are studying to add impurities to control the properties of semiconductors. Fowler gives Pearson a silicon wafer containing gallium impurities, Pearson will be immersed in lithium solution, the adsorption of lithium after the formation of p-n junction. Pearson then the current meter connected to the silicon, it sunshine, so that everyone is surprised that the ammeter obviously jump.
Pearson knew that Joe was doing research, so go and tell his friends not to waste time on selenium solar cells, so Joe Ben turned to silicon again.
The three scientists spent a few months working together to improve the nature of their silicon solar cells. One of the problems is that it is difficult to create electrodes that can be electrically conductive with silicon cells. Another problem is that lithium will move over time at room temperature, allowing the pn junction to travel more distant from the sun The In order to solve this problem, they try to use different impurities, and finally the use of arsenic and boron, can be made to stay in the vicinity of the p-n junction, they also found that the electrode can be boron - arsenic silicon cells have good conductive contact. So in the design to do some other improvements, they will be a few solar cells together to create what they call the "solar cell."
Bell Labs announced the invention on April 25, 1954 at Murray Hill, New Jersey, where they demonstrated their solar panels, turning it into a small toy Ferris wheel and a solar power Of the radio transmitter.
The earliest silicon solar cells convert solar energy into electrical energy efficiency of about 6%, compared with the previous solar cells is a great improvement.
"The New York Times" commented that silicon solar cells "may mark the beginning of a new era, and ultimately one of the most desired dreams of mankind, that is, the use of almost unlimited amount of solar energy in human civilization.
The initial cost of silicon solar cells was expensive, and it was not very successful to commercialize it early, but over the years, solar cells had been widely used to supply the power needed by satellites, and were later used for other purposes.
Qiaobin quickly simplified the manufacturing process of solar cells, and even developed a solar cell science experiment for secondary school students. Joe Bin, Fowler and Pearson were elected to the National Inventor Hall of Fame in 2008. Now, solar cells are available on a variety of devices, from hand-held calculators to solar panels on the roof. The design of the improved, coupled with advanced materials, has now been able to build solar cells with efficiencies greater than 40%. The research and development of solar cells continues, with the goal of reducing costs and improving efficiency so that solar power is more competitive than fossil fuels.