Photovoltaic efficiency is the ratio of the electric power produced by a photovoltaic solar cell to the amount of solar irradiance on the device. Photovoltaic solar cells are solid state devices made from various types of semiconductor materials that convert the sun’s light energy directly into electrical energy. Their current-voltage (I-V) characteristics are a function of the light source, design their silicon based materials.
The rated power of a solar cell or photovoltaic panel is measured under internationally specified test conditions. The standard test conditions, or STC of a photovoltaic solar panel defines the manufacturer’s voltage, current and wattage rating. But since these conditions are not typical of how PV modules and arrays operate in the field, actual performance is somewhat less than at STC.
Solar cell I-V characteristics curves show the current and voltage characteristics of a particular photovoltaic cell, module or array in order to give a detailed description of its solar energy conversion ability and efficiency at different light intensities. Solar cell I-V characteristics curves are use to measure a cells open-circuit voltage, short-circuit current, fill factor and efficiency with the rating of a PV cell or panel depending on these parameters
Photovoltaic cells turn the photons from sunlight into electrons producing a current flow, thus photovoltaic PV cells are powered by incident sunlight and so are commonly called solar cells. Solar cells are made using silicon based semiconductor materials with different electrical properties. An n-type semiconductor material with excess negatively charged electrons is fused together with a p-type semiconductor which has an excess of positively charged holes to create a p-n junction. When a photon of light hits this p-n junction, electrons are release to form an electrical current
Photovoltaic solar cells come in many different forms with the three main types of photovoltaic cell being Monocrystalline silicon, Polycrystalline silicon and Thin Film silicon. Crystalline silicon is the most common technology used to produce photovoltaic cells representing about 90% of the market today. The conversion efficiency for a monocrystalline cell ranges between 15 to 20% with polycrystalline lower between 10 to 14%. Thin film photovoltaics are produced by printing or spraying a thin semiconductor layer of photovoltaic material onto a glass, metal or plastic foil substrate making them cheap to manufacture.
