How
do solar cells work? That’s a billion dollar question. That’s
because the business of using solar energy for homes and businesses
has increased exponentially in the last several years. Because the
market is growing, there are several competing companies that each
are trying to best understand how these items can work even better.
However, before a better cell can be created, it is important first
understand how these systems work already. Having a solid basis of
knowledge will allow for a more productive discovery process in the
future.
In being able to convert light into electricity, these solar cells
use similar technology to that which is used by the computer industry
to create computer chips. Before anything else happens in this conversion
process, the cell must absorb the light.
The light is the source of all energy and acts as the instigator in
the whole process. Once the light has been absorbed into the cell,
the electrons in the material from which the cell is made experience
an increase in energy. This higher level of energy allows the electrons
to be free and move around the material.
But, things need to happen quickly after this initial step of the
light hitting the solar cells takes place. This is true because this
elevated level of energy stays in effect for only a few minutes before
the normal level of activity returns. A device called a pn junction
is often used in these cells.
The pn junction actually is made up of two separate regions of a semi-conductor
material. The material that is most commonly used is silicon. The
name pn junction comes from the fact that one side of the junction
is called the p-type region while the other side is called the n-type
region.
It is the purpose of the pn junction to collect the carriers before
they have had time to lose all of the energy that was initially gained
from the effect that the light has on the solar panel. In the p-type
material, the electrons are able to quickly gain energy when they
are exposed to any kind of light, but if not captured, they rapidly
will return to their original low-energy position.
The difference between p and n types is the fact that if the electrons
are able to move into the n-type region, they stay at a high energy
level and are no longer able to lower and return to their initial
state.
The process of moving these electrons from one area to the next is
what is known as collection. After the light generator is collected,
there are a couple of options concerning what can happen next. First
of all, it can be extracted from the device and then be able to give
a current. Or, secondly, the energy can simply remain inside of the
device. If this is the choice taken, the voltage will rise.
This rise of voltage is referred to as the photovoltaic effect. When
mention is made of PV panels, the PV also stands for photovoltaic.
It is this combination of voltage and a current together that create
an output of power from a solar cell.
The electrons that are part of the current leave their energy behind
and then return to the n-type region back at the same low level at
which the process began. After this happens, the whole process begins
once again.
The use of solar cells does not depend on a person’s knowledge
concerning how these cells work, however it does help a person better
understand the way their solar energy system in their home works in
case a situation comes up when a homeowner must have a basic knowledge
of this process.