photon
1. A particle of light that acts as an individual unit of energy.
2. A quantum of electromagnetic energy that can be considered as a particle with no mass, no charge, and traveling at the speed of light.
As "packets" of light they can be individually counted and used to build up a picture of; for example, a distant galaxy.
photovoltaic array
1. An interconnected system of photovoltaic modules that function as a single electricity-producing unit. The modules are assembled as a discrete structure, with common support or mounting.
The modules are assembled as a discrete structure, with common support or mounting; in smaller systems, an array can consist of a single module.
photovoltaic cell
The smallest semiconductor element within a PV module to perform the immediate conversion of light into electrical energy (direct current voltage and current). Also called a solar cell.
photovoltaic conversion efficiency
The ratio of the electric power produced by a photovoltaic device to the power of the sunlight incident on the device.
photovoltaic device
A solid-state electrical device that converts light directly into direct current electricity of voltage-current characteristics that are a function of the characteristics of the light source and the materials in and design of the device.
Solar photovoltaic devices are made of various semiconductor materials including silicon, cadmium sulfide, cadmium telluride, and gallium arsenide, and in single crystalline, multicrystalline, or amorphous forms.
photovoltaic effect
The phenomenon that occurs when photons, the "particles" in a beam of light, knock electrons loose from the atoms they strike.
When this property of light is combined with the properties of semiconductors, electrons flow in one direction across a junction, setting up a voltage.
With the addition of circuitry, current will flow and electric power will be available.
photovoltaic generator
The total of all photovoltaic strings of a photovoltaic power supply system, which are electrically interconnected.
photovoltaic module
The smallest environmentally protected, essentially planar assembly of solar cells and ancillary parts, such as interconnections, terminals, [and protective devices such as diodes] intended to generate direct current power under unconcentrated sunlight.
The structural (load carrying) member of a module can either be the top layer (superstrate) or the back layer (substrate).
photovoltaic panel
Often used interchangeably with photovoltaic module (especially in one-module systems), but more accurately used to refer to a physically connected collection of modules (for example, a laminate string of modules used to achieve a required voltage and current).
photovoltaic system
A complete set of components for converting sunlight into electricity by the photovoltaic process, including the array and balance of system components.
photovoltaic(s); PV
Referring to the direct conversion of light into electricity.
photovoltaic-thermal (PV/T) system
A photovoltaic system that, in addition to converting sunlight into electricity, collects the residual heat energy and delivers both heat and electricity in usable form. Also called a "total energy system".
physical vapor deposition
A method of depositing thin semiconductor photovoltaic films.
With this method, physical processes, such as thermal evaporation or bombardment of ions, are used to deposit elemental semiconductor material on a substrate.
plates
A metal plate, usually lead or lead compound, immersed in the electrolyte in a battery.
polycrystalline silicon
A material used to make photovoltaic cells, which consist of many crystals unlike single-crystal silicon.
—The information for the entries in this unit were compiled primarily from data
provided in the following source:
"U.S. Department of Energy, Energy Efficiency and Renewable Energy"
consisting of definitions of many important terms having to do with electricity,
power generation, concentrating solar power (CSP), solar heating, solar lighting,
and solar electricity, also known as photovoltaic (PV).
Information was also compiled from the
Academic Press Dictionary of Science and Technology; Edited by Christopher Morris;
Academic Press; Harcourt Brace Jovanovich, Publishers; New York; 1992;
as well as,
McGraw-Hill Dictionary of Scientific and Technical Terms, 4th edition;
Sybil P. Parker, editor in chief; McGraw-Hill, Inc.; 1989.
Index of additional Scientific and Technological Topics.
