At McMaster University in Hamilton, Ontario, a team of scientists are working on an
ingenious way of solving the low efficiency problem of modern solar panels by growing
nanowires. Todays silicon based solar cells converts into electricity only 10 to 15
percent of the energy they absorb.

To put a nanowire into prospective for you:

1 nanometer = 1 billionth of a meter
800 nanometers = width of a human hair
100 nanometers = width of a nanowire
1/100th of a human hair = heigth of a nano wire

Let’s put it this way – you CAN NOT see it. So, don’t try, you will get severe eye
strain.

In conventional cells, the direction of the absorption of the sunlight is the same
direction which the electrons (electricity) have to escape. But, with nano wires,
the direction in which they absorb light is along their long length, but the direction
in which to collect the electricity is sideways, in a different direction than the
absorption, which makes it very easy to collect electricity out of these solar cells.

How to make nanowires, you ask? Well, first you seed a silicon base wafer with tiny
droplets of gold in a clean room. They use gold to grow nanowires because of it’s
stable molecular structure.

A silicon wafer is loaded into a chamber where a little pot of gold is heated up by
a beam of electrons, a tiny bit of the gold evaporates and coats the wafer with a
minute film of gold.

Next, they place the wafer in an evaporator (with a long fancy name) that has
containers each holding different materials (which they do not elaborate on), heat up
the containers, and the materials evaporate and forms nanowires wherever the gold
particles are resting on the surface of the wafer.

The whole process takes about 30 minutes.

Under an electron microscope you can see a little gold cap on the individual nano
wires because the growth of the wire takes place underneath the gold, pushing the
gold up as it grows – (too cool!)

Still in the early stages of the research, they are seeing efficiency of a few percent,
about the same as solar cells in the 1950′s. But the progress shows they should
expect an efficiency in the range of 50 – 60 percent. About 4 times more electricity.

That means in a few short years, you can get quadruple the electricity from the same
size arrays of today.

Imagine, small roof top arrays supplying all your energy needs.

Tags: billionth, different materials, efficiency problem, electric, electrical, electricity, electron microscope, energy, evaporator, eye strain, fancy name, gold cap, heigth, lights, little pot, mcmaster university, minute film, molecular structure, nanowire, pot of gold, roofing, silicon base, silicon wafer, solar cells, tiny droplets, width of a human hair, wire

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