Author: Daniel Stouffer Added: July 12, 2008
The following article explains in varying levels of detail; how a solar cell converts sunlight energy into free electrons, which is called the photoelectric effect and how, from the physical perspective, the use of silicon moves electrons through various states to produce useful solar generated electricity. Einstein was awarded the Nobel Prize in Physics for his work on the photoelectric effect, not for his work on relativity. Little did one know that the same people who helped us calculate everything under the sun is also the same person helping to bring renewable solar energy to the masses. Solar Electricity and the Photoelectric Effect The photoelectric effect is a key concept, since it is the way sunlight is converted into free electrons as light interacts with the solar cell. Without the creative work of Albert Einstein, the physical characteristics of sunlight might not be known. Never mind the impact and Earth-altering opportunities to power your home using solar generated electricity that his ideas inspired all these years later. Think of sunlight not as a wave but as a beam of photon particles for the purposes of explain the technical details of how home solar energy systems work. These bundles of energy penetrate the silicon lattice structure inside the solar cells making up a home solar panel and transfer their energy to an electron in the outer layer of the silicon atom. When a single electron gains enough energy from the penetrating photons, it breaks free and floats around the lattice structure, no longer bonded. An electron has a negative charge when it is knocked free during the photoelectric effect. The silicon atom that loses the electron, which had a neutral charge with the electron, now has a positive charge without it. Remember back to high school chemistry. Suddenly, these classes seem relevant when learning about solar generated electricity. Who would have known? When an electron is removed from this lattice structure or matrix in this fashion, it creates a hole in the outer layer of the lattice where the electron was. A nearby electron with a negative charge soon fills the hole. The electron that moves in has a positive charge. It can be described like the balancing of an equation; i.e. when one silicon electron consisting of a negative charge is transferred in...another particle, in this case an electron with a positive charge, is bumped out and moves out. As photons of sunlight penetrate the silicon and knock electrons loose they transfer their energy. Electrons with negative charges are transfered into holes in the chemical structure of the silicon atom and into positive holes that appear once the electrons move out. Sort of confusing but it really is like two layers of Swiss cheese laid side by side. Holes, or bubbles, from in one layer and move over to fill the holes in the other layer. The total number of holes stays the same and every bubble makes a circular path from one side, where they are pushed out, to the other side where they are absorbed in. Something similar happens when electrons are forced out of and into silicon waffers. For this phenomenon to be work, a one-way flow of electrons needs to be created to generate electric current. This one-way flow of electrons occurs when the sunlight in the form of photons continually strikes the solar cells inside a home solar energy system. Incredibly enough, this process is the secret sauce that allows electricity to be produced from ordinary sunlight. Thanks to Albert Einstein and the photoelectric effect home owners now have the opportunity to buy solar energy systems or rent solar panels to self-produce energy for their home.
--- At Solargies, our goal is to spread the use of renewable solar energy as simply and as rapidly as possible. Daniel Stouffer is a freelance writer and solar energy consultant. Find out how to rent a solar energy system at: => http://www.reThinkingSolar.com
Comments
| 
