What is the principle of solar cell? Write its advantages and disadvantages
In photoelectric effect when radiation is incident on a metal surface electron are ejected. In photovoltaic effect, certain materials being exposed to radiation generates electron hole pairs available for conduction. As a result a voltage is developed across the material. The radiation energy E= hϑ is required to be greater then the band gap energy Eg of the material. This is a phenomenon in which light energy is converted into electrical energy.
⦁ Environmentally friendly.
⦁ No noise, no moving parts.
⦁ No emission.
⦁ Minimum maintenance required.
⦁ Long lifetime, up to 30 years.
⦁ PV operator even in cloudy weather condition. Disadvantages:-
⦁ PV cannot operate without light .
⦁ High initial costs that overshadow the low maintenance costs and lack of fuel costs.
⦁ Large area needed for large scale applications.
⦁ PV generates direct current special DC appliances or an inverter are needed.