Cell Construction

• Solar cells are made predominantly from pure silicon. Silicon naturally does not carry a positive or negative charge, but when it is combined with another charged element, it will take on that charge. For electricity to flow, a conducive link must be created between a positive and negative charge--therefore, solar cells are made up of two plates, one positive and one negative. The negatively charged plate in a solar panel is usually made from a silicon and phosphorus mixture, while the positively charged plate is often created from a combination of silicon and boron. The two plates of the solar cell are joined through a network of wires.
  
  

Electron Transfer

• Solar cells work when natural sunlight, rich in photon particles, shines on the negative plate and excites the electrons that surround the bonded silicon and phosphorus atoms. The additional electron that makes the plate negative is freed from the atoms and travels along the connective wiring to the electron-hungry and positively charged atoms on the silicon and boron plate. This electron transfer creates energy, and the process will continue as long as photons shine on the negative plate. Energy that is not initially used can be transferred from the cell and stored in chemical batteries for future use. The amount of power a solar cell can produce is directly related to the size of the cell, as the number of electron transfers occurring at the same time determine the amount of energy harvested. Therefore, the greater the panel's surface area the more reactions can occur.