Photovoltaic cells are renewable sources of energy. Main principle involved here is ‘photovoltaic effect’ where a photovoltaic cell converts sunlight into electricity. Electron-hole pairs are created when light strikes the photovoltaic cell. Since no materials are being wasted, it is known as a renewable process. Solar cells are composed of various semiconducting materials. Silicon is the most popular candidate since it is the second most abundant element in the earth’s crust. The other advantages of silicon are silicon wafers are thin, non-toxic etc. A large area p-n junction diode can be used as a photovoltaic cell. When sunlight strikes a photovoltaic cell, photon knocks an electron from a silicon atom. Thus electron is emitted and a hole is created in silicon.
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