Lect17 -- Solar

Electrons diffuse to fill holes images from ccmr

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Unformatted text preview: tricity Doped Silicon: The heart of a PV cell “n layer”: Si with ~1 ppm P or As Electron rich since P, As have 5 valence electrons, but only need 4 for bonding. This leaves one e- free “p layer”: Si with ~1 ppm B B has 3 valence electrons, leaving "holes" to be filled. Electrons diffuse to fill holes images from CCMR Educational Programs The workings of photovoltaics Electrons migrate from n layer to p layer. Negative charge accumulates at top of p layer. images from CCMR Educational Programs Generating current from a PV cell Photons kick electrons from one side to another, generating an electric field. Photons must have sufficient energy to provide kick. images from CCMR Educational Programs Add conductors to top & bottom CCMR Educational Programs Assembling a generic PV cell CCMR Educational Programs Making electricity from PV Utility grid Sun DC PV-array Inverter AC Battery •  •  •  •  •  Sunlight is turned into DC voltage/current by PV Can charge battery (optional) Inverted into AC Optionally connect to existing utility grid AC powers household appliances Large PV installations N...
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This document was uploaded on 12/05/2013.

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