An Investigation Into the Factors Affecting the Voltage Output of a Solar Cell

2372 Words5 Pages

An Investigation Into the Factors Affecting the Voltage Output of a Solar Cell

My aim is to try and find out how much the voltage is affected when

exposing different sized areas of a solar cell to a light source. From

this I will also establish the energy of each photon and

approximately, the number of freed electrons, which can make an

electric current flow.

I know that light consists of packets or quanta of energy called

photons. When electromagnetic radiation such as light shines on

materials (usually metals), which emit electrons the light photons

containing energy are captured by the electrons. This means that the

electron absorbs the energy from a photon thus allowing it to escape

from the surface of its material. For each light photon landing on the

surface of a material which emits electrons, an electron can be

'free'.

I know that solar cells contain thin wafers of silicon protected by

glass. When light photons strike the surface of the solar cell, energy

from the photon is absorbed by an electron. The electron needs a

certain minimum energy to escape the material but excess energy or

surplus energy is transferred to the electron as kinetic energy. Thus

creating an electric force, this pushes the electrons around a

circuit, known as an electric current, when the solar cell is

connected up. The size of the voltage depends on the number of flowing

or 'freed' electrons.

Energy of photon

Energy required to remove electron from metal

Kinetic energy of escaping electron

===================================

= +

From looking at the methodology of my preliminary experiment I know

that there are many other variables. In my preliminary experiment my

main aim was to investigate as many other variables as I could think

of, which might affect the output or voltage. I did this because by

considering all the other variables I am able to regulate them,

keeping my experiment as fair as possible. The other variables or

independent variables that I have noted from my preliminary

Open Document