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| 1. |
cellExplain construction and working of Photovoltaic |
| Answer» <p>A solar cell, or photovoltaic cell, is an electrical device that converts the energy of light directly into electricity by the photovoltaic effect, which is a physical and chemical phenomenon.</p><p>It is a form of photoelectric cell, defined as a device whose electrical characteristics, such as current, voltage, or resistance, vary when exposed to light.</p><p>Solar cells are the building blocks of photovoltaic modules, otherwise known as solar panels.The operation of a photovoltaic (PV) cell requires 3 basic attributes:</p><p>The absorption of light, generating either electron-hole pairs or excitons.</p><p>The separation of charge carriers of opposite types.</p><p>The separate extraction of those carriers to an external circuit.</p> <p>Construction-It essentially consists of a silicon PN junction diode with a glass window on top surface layer of P material is made extremely thin so, that incident light photon’s may easily reach the PN junction.</p><p>Working of solar cell1) Solar cell works under the principle of photovoltaic effect-when light is incident on ‘P-N’ junction a potential gets developed across the junction, this potential is capable of driving a current through the circuit.</p><p>2) Hence light energy is getting converted to electrical energy.</p><p>3) Here electrons absorbs photons having energy greater than the band gap energy hence they can make transition from the valence band to the conduction band & hence contributes current.</p><p>4) The wavelength of light is given by the relation,Eg=h=hc/λ=1.24</p> | |