Finally : cheap DIY selfmade solar cell with common materials !

[ResinRat2]

Hi ResinRat2,
what is the ionisation energy level for Aluminium ?

listed here: http://www.lenntech.com/Periodic-chart-elements/Al-en.htm

The value is given as: 577.4 kJ.mol -1

I guess the sun will just reflect from the aluminium and
not pop some electrons out of the foil.

ALso if you have a bit moisture inside your air
a high ohmic digital multimeter will just measure
0.6 Volts between the graphite and the alufoil.
Just wet fingertouches are enough between your
"nonconductive" paper to cause this.

If you try it with a lower impedance analog meter you
will probably measure no voltage...or much less.

It does seem strange that my reading is 0.6 V as you say. Perhaps it is moisture.

Also the electrons will not just fly through the air a few inches to
go to the graphite paper..
When you would need vaccuum it will get again too expensive..

Actually, I got the idea from a Physical Chemistry Answer manual that showed a drawing of a device used to measure ionization energy of a metal that was a cylinder with the metal at the bottom that reflected a laser beam into the cylinder walls. The metal was not cone shaped but the cylinder was in a vacuum. So I think the electrons may fly a short distance. I have no idea how far. Maybe it would be better to have this filled with a liquid medium to transport the electrons like the Gratzyl cell. Maybe iodine or chlorine bleach. I need to think about this.

I guess the best way would be to find cheap materials that have the
right ionisation energy level to sunlight and have them sprayed or
painted onto graphite paper and then use a transparent conductive electrode
layer to paint over it.
The question is
what is the best and cheapest transparent conductive electrode layer that can
be easily selfmade.


Have a look at these 2 artificial Leaf videos:

http://www.youtube.com/watch?v=XZ6XqEsutcM
http://www.youtube.com/watch?v=0l6-N0ba7jg

Thanks for the input Stefan. I need to consider this a bit and do a few more experiments.

[hartiberlin]

listed here: http://www.lenntech.com/Periodic-chart-elements/Al-en.htm

The value is given as: 577.4 kJ.mol -1

How many electronVolts are this ?
Does sunlight have enough energy to ionize some outer shell electrons
from the Aluminium foil ?

It does seem strange that my reading is 0.6 V as you say. Perhaps it is moisture.

I once had a graphite cylinder in a plastic 1 cm isolated to a metal
rod with no water in there and the moisture from the air on the plastic
already was enough to have a galvanic action from this "electrolyte moisture" and display around 0.6 Volts
on my digital voltmeter...so it was just a basic galvanical cell.

In solar cell research you have to see, if it is all not just galvanical actions
which consumes electrodes... sometimes these effects also mix,
so some effect is solar conversion and some is galvanic,
if you don´t choose the electrodes right...or use water based solutions
with it.

Good luck in your experiments.

Regards, Stefan.

[ResinRat2]

How many electronVolts are this ?

http://www.ask.com/bar?q=ionization+energy+of+aluminum&page=1&qsrc=66&ab=4&u=http%3A%2F%2Fwww.sunysccc.edu%2Facademic%2Fmst%2Fptable%2Fal.html

It converts to 5.986 eV

What is ordinary sunlight? Is it enough to knock out the electron?

[hartiberlin]

Hi,
I found it:

http://www.daviddarling.info/encyclopedia/B/AE_band_gap.html

Band gaps and solar cells

To free an electron, the energy of a photon must be at least as great as the band gap energy. However, photons with more energy than the band gap energy will expend that extra amount as heat when freeing electrons. So, it's important for a solar cell to be "tuned" â€" through slight modifications to the silicon's molecular structure â€" to optimize the photon energy. A key to obtaining an efficient solar cell is to convert as much sunlight as possible into electricity.

Crystalline silicon has a band gap energy of 1.1 electron-volts (eV). (An electron-volt is equal to the energy gained by an electron when it passes through a potential of 1 volt in a vacuum.) The band gap energies of other effective photovoltaic semiconductors range from 1.0 to 1.6 eV. In this range, electrons can be freed without creating extra heat.

The photon energy of light varies according to the different wavelengths of the light.

The entire spectrum of sunlight, from infrared to ultraviolet, covers a range of about 0.5 eV to about 2.9 eV. For example, red light has an energy of about 1.7 eV, and blue light has an energy of about 2.7 eV. Most solar cells cannot use about 55% of the energy of sunlight, because this energy is either below the bandgap of the material or carries excess energy.

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

So it is important to have a material that has the same
bandgap as in the range of the sunlight.

So 5.986 eV from Aluminium is much too high.
You would not loose any electrons just with sunlight.

You need a material that is in the 1.5 eV range about for
good conversion.

Can you please lookup which materials are in this range ?

Many thanks.

[infringer]

New product worth checking into for this project!

Wire glue

This is a new conductive glue that can be used in place of soldering...

Check for it at think geek.