The photovoltaic effect is the phenomenon where electrical potential is generated by materials when they are exposed to a source of electro-magnetic energy. The intensity of the photovoltaic effect is strongly correlated to the intensity of the light source, the constituent wavelengths of the supplied light and the physical makeup and structure of the incident material. It has been found that the greatest power output available from the photovoltaic effect, if using sunlight as your electro-magnetic power source, can be generated using either silicon or some other chemically-related natural or man-made electrically semi-conductive material.
Photovoltaic effect in detail
Through the manipulation of small amounts of different compounds, the electrical behaviour of semi-conductive materials can be adjusted to be electrically stable with either a slight positive (p-type) or negative (n-type) charge. In power generating solar cells, a layer of n-type is laid down on a layer of p-type and each electrically bonded to their own electrode. When the surface of the n-type layer is exposed to sunlight, the photovoltaic effect is induced by the stream of photons that constitute light. Striking the individual atoms that make up this n-type layer, electrons jump in energy levels from the more stable valence bands to the higher energy conducting band. Since the n-type material is already negatively charged, the freed negative electrons are driven to the p-type layer. If the electrode of the p-type layer is electrically connected to the n-type layer, an electrical circuit is completed and current will flow. When this current is combined with the output of other cells, it creates enough power to provide useful levels of photovoltaic electricity.
While solar panels do good work in harnessing the sun's energy, they do not work with perfect efficiency. However, engineers are working to improve this solar technology and build more efficient solar panels to truly capture the power of the sun.