Photovoltaic or Solar Cell

Abstract

This article is about the working of a photovoltaic cell or solar cell.

Photovoltaic cell is a device which operates on the principle of photovoltaic effect. The potential barrier in an open circuited non-illuminated p-n junction adjusts itself so that the resultant current is zero. When the junction is illuminated electron-hole pairs are generated on each side of the junction. As the minority carriers (electrons of p-side and holes of n-side) move down the potential barrier, it causes an increase in reverse current. But since the diode is an open circuit the resultant current must be zero. So the majority current must increase by the same amount as the minority current. The increase in majority current is effected by the decrease in barrier height in the presence of incident light. As a result a potential difference develops across an open circuited illuminated p-n junction (it develops due to accumulation of excess majority carriers in their respective regions. This is known as photovoltaic effect.