The principle of operation of a PV cell

In 1839, French physicist Alexander E. Becquerel discovered the photovoltaic effect involving conversion of solar energy into electrical energy in semiconductor element.

Photovoltaic cell consists of high-purity silicon. On the silicon, a PN (positive-negative) junction was formed as a potential barrier. Photons falling on the PN junction cause the rise of pairs of opposite electrical charge carriers (electron – hole), which as a result of the presence of PN junction are separated in two different directions. Electrons go to the semiconductor N and holes go to the semiconductor P. The voltage will arise on the junction. Because the separated electrical charges are redundant carriers, having so called, infinite life and a PN junction voltage is constant, the junction, on which the light falls acts as a stable electric cell.

 

Figure: Construction of a photovoltaic cell

1. semiconductor n
2. p-n junction
3. semiconductor p
4. 5. metallic connection
6. anti-glare material