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THE PHOTOVOLTAIC EFFECTCynthia M. Rollins
TOPICS
What is the photovoltaic effect? Some history How the photovoltaic effect works? Anatomy of a solar cell
WHAT IS THE PHOTOVOLTAIC EFFECT
Photovoltaic’s is the direct conversion of light into electricity at the atomic level.
HISTORY In 1839, Alexandre Edmond Becquerel
observed the photoelectric effect via an electrode in a conductive solution exposed to light.
In 1887, Heinrich Hertz observed the photoelectric effect and the production and reception of electromagnetic (EM) waves.
In 1902, Philipp Eduard Anton von Lenard observed the variation in electron energy with light frequency
Albert Einstein's mathematical description in 1905 of how the photoelectric effect was caused by absorption of quanta of light.
HOW THE PHOTOVOLTAIC EFFECT WORKS Sunlight is composed of
photons (the amount of energy in a
photon being proportional to the frequency of its light).
When photons strike a solar cell, the vast majority are either reflected or absorbed (some really high-energy
photons will blow right through, but they're of no concern here).
HOW THE PHOTOVOLTAIC EFFECT WORKS When a photon is absorbed, its energy is
transferred to the semiconductor electron escapes from its normal position
associated with that atom. The electron causes a hole to form. Each photon with enough energy will
normally free exactly one electron, and one hole. Note that both electrons and holes are
mobile, and as such can be current carriers.
HOW THE PHOTOVOLTAIC EFFECT WORKS
ANATOMY OF A SOLAR CELL
TOPICS COVERED
What is the photovoltaic effect Brief history How photovoltaic effect Work
Quantum level How to calculate the energy of a photon
Basic anatomy of a solar cell
http://en.wikipedia.org/wiki/Photovoltaic_effect#History
http://science.howstuffworks.com/solar-cell3.htm
http://www.solarbotics.net/starting/200202_solar_cells/200202_solar_cell_physics.html
http://en.wikipedia.org/wiki/Energy_use_in_the_United_States
http://science.nasa.gov/headlines/y2002/solarcells.htm