Solar panel

A solar panel is a device that collects and converts solar energy into electricity or heat which can be used by (for example) nearby buildings. Solar photovoltaic panels can be made so that the sun's energy excites the atoms in a silicon layer between two protector panels. Electrons from these excited atoms form an electric current, which can be used by external devices. Solar panels were in use over one hundred years ago for water heating in homes. Solar panels can also be made with a specially shaped mirror that concentrates light onto a tube of oil. The oil then heats up, and travels through a vat of water, instantly boiling it. The steam created turns a turbine for power
The history of solar panels dates back to 1839, when French physicist Antoine César Becquerel discovered the photovoltaic effect during an experiment involving an electrolytic cell that was made up of two metal electrodes placed in an electrolyte solution. Becquerel discovered that when his device was exposed to light the amount of electricity generated increased.[2]

Then in 1883, the first genuine solar cell was built by Charles Fritts. Fritts' solar cell was formed by coating sheets of selenium with a thin layer of gold.[3]

Between 1883 and 1941 many scientists, inventors and companies experimented with solar energy. During these years Clarence Kemp, a Baltimore inventor patented the first commercial water heater powered from solar energy. In addition, Albert Einstein published his thesis on the photoelectric effect and a few years later received the Nobel Prize in Physics for his research. William Bailey, an employee of the Carnegie Steel Company, invented the first solar collector with copper coils contained in an insulated box.

In 1941, Russell Ohl, an American inventor who worked for Bell Laboratories, patented the first silicon solar cell. Ohl’s new invention led Bell Laboratories to produce the first crystalline silicon solar panel in 1954. This solar cell achieved a 4% return on energy conversion. In the years that followed, other scientists continued to improve on this original solar cell and began to produce solar cells with 6% efficiency.

The first large scale use for solar electrical energy was space satellites. With government backing much of the research the US was able to produce a solar cell with twenty percent efficiency by 1980 and by early 2000 had produced solar cells with 24% efficiency. As of November 2007 two companies, Spectrolab and Emcore Photovoltaics dominate world solar cell production and have the ability to produce cells with 28% efficiency

The basic element of solar panels is pure silicon. When stripped of impurities, silicon makes an ideal neutral platform for transmission of electrons. In silicon’s natural state, it carries four electrons, but has room for eight. Therefore silicon has room for four more electrons. If a silicon atom comes in contact with another silicon atom, each receives the other atom's four electrons. Eight electrons satisfy the atoms' needs, this creates a strong bond, but there is no positive or negative charge. Silicon atoms combine for years to produce a large piece of pure silicon. This material is used on the plates of solar panels. Combining silicon with other elements that have a positive or negative charge can also create solar panels.[5]

For example, phosphorus has five electrons to offer to other atoms. If silicon and phosphorus are combined chemically, the results are a stable eight electrons with an additional free electron. The silicon does not need the free electron, but it can not leave because it is bonded to the other phosphorous atom. Therefore, this silicon and phosphorus plate is considered to be negatively charged.[5]

A positive charge must also be created in order for electricity to flow. Combining silicon with an element such as boron, which only has three electrons to offer, creates a positive charge. A silicon and boron plate still has one spot available for another electron. Therefore, the plate has a positive charge. The two plates are sandwiched together to make solar panels, with conductive wires running between them.

Photons bombard the silicon/phosphorus atoms when the negative plates of solar cells are pointed at the sun. Eventually, the 9th electron is knocked off the outer ring. Since the positive silicon/boron plate draws it into the open spot on its own outer band, this electron doesn't remain free for long. As the sun's photons break off more electrons, electricity is then generated. When all of the conductive wires draw the free electrons away from the plates, there is enough electricity to power low amperage motors or other electronics, although the electricity generated by one solar cell is not very impressive by itself. When electrons are not used or lost to the air they are returned to the negative plate and the entire process begins again.