Introduction to Solar cells

solar cells are used for the generation of electrical energy i.e voltage by using photon energy from sun according to the principle called photovoltaic effect. These cells are also used for generating heat energy.

Solar cells are generally made of semiconducting materials such as silicon, galliumarsanide(GaAs) etc.
we need an impure silicon solar cell for the conversion of light to voltage, in order to have the structural imbalance. This imbalance leads to stable bonding with the result of giving output as a electrical parameter, this is explained clearly in below fig. below.

But our interest is not on working of solar cell but on a device that works like natural sun


Reference:
http://science.howstuffworks.com/solar-cell6.htm