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