Solar-Cell

Description:

Solar cell, which is also known as photovoltaic cell, converts solar (light) energy directly into electrical energy.

Solar cell is a P-N junction diode that has very thin layer of P-type semiconductor (thickness is in μm) so that light can reach the junction.

The photon that is reaching the junction should have energy greater than the energy gap.

Metallic contacts are formed on both the layers for external circuit connections. At the top silver fingers are used, as silver is the best conductor and they are used to absorb photo electrons.

This displacement of charges sets up a potential difference across two regions, with P-side as positive and N-side as negative. If external load RL is connected, current flows through it and we get electrical energy.

Typically, a solar cell can generate photo voltage from 0.5 V to 1.2 V.

V-I characteristic of solar cell

Applications of solar cell

• Charging storage batteries.
• Charging satellite batteries.
• Pumps and other electronic appliances in the far-off areas use solar cell.
• Radiophones.