Photovoltaic features

The term "photovoltaic" refers to a technology, which uses a device to produce free electrons when exposed to light and thus create an electric current. The word photovoltaic derives from the Greek word "photo" meaning light and the modern word "Volt" or "Voltage" meaning a unit of electrical potential (named in honour of the Italian physicist Alessandro Volta (1745–1827), who also is attributed with inventing the first chemical battery. This is the subject of debate, though, as working batteries may have been used in antiquity.

Photovoltaic technology converts sunlight into electrical energy in a direct way as opposed to the circuitous approach of solar thermal technologies that capture sunlight to heat a gas or fluid and subsequently use heat engines to generate electricity.

The most common PV technology uses solar cells made of semiconductor materials (such as silicon or germanium) doped with small amounts of impurities (typically metals or metalloids).

In simple terms, when sunlight strikes a cell, a certain portion of its energy is absorbed within the semiconductor material. The absorbed energy knocks electrons loose, allowing them to flow freely under the influence of electric fields in a closed electric circuit.

Solar cells have inbuilt electric fields that force the released electrons to flow in a certain direction. Metal contacts on the top and bottom of the PV cell enable the cell to generate a current in an external circuit. This current, together with the cell's voltage (which is a result of its in-built electric fields), defines the power (or wattage) that a solar cell can produce.

This direct current (DC) can be used to recharge batteries and run direct current devices, or can be converted via power electronic inverters into alternating current (AC), the form of electricity most commonly used in homes, offices and industry.

The word photovoltaic derives from the Greek word "photo" meaning light and the modern word "Volt" or "Voltage" meaning a unit of electrical potential (named in honor of the Italian physicist Alessandro Volta (1745–1827), who is attributed with inventing the first chemical battery. This is the subject of debate, though, as working batteries may have been used in antiquity).