Scientists in Arizona

Scientists in Arizona are using screen-printing, a
technique developed for printing fabrics, paper and
to produce plastic, glass and metal solar cells.
The basic materials of a photovoltaic cell (solar cell)
are inexpensive. The organic manufactured by
Ghassan Jabbour and colleagues at the University of
Arizona in Tucson have about 11/4 of the efficiency
of commercial silicon solar cells, which turn 10-20
per cent of light energy into electricity. But, being
cheap to produce, they can make up the loss in
quantity what they lack in quality. Now the Japan
screen printed solar cells are even better than that!

In conventional Screen - printing, a taut piece of
screen mesh fabric is stretched over a wood frame,
you can buy the screens already made and the materials
from any screen printing shop or screen printing supply
company in your area or on the internet. Also you might
want to check with your local art store, sometimes they
have full kits etc...

The screen is then masked off using masking tape,
For example: a 5" x 5" square area. the screen outside
of the masking tape is then coated with a block out
liquid or paint, this is so when you apply your semiconducting ink that you mixe, it will go
through just the area that you masked off when you apply a rubber squeegee to it. The
screen can then be placed on any table top and hinges attached to the back of the wood
frame and the table, this will insure the screen can move up and down. Then get a small
wood paint stick and using a small nail, hammer one end to the front side of wood frame.
This will be your kick leg and will help keep your screen in an upward position when
needed. Take a 5" x 5" piece of glass and place it right under the open 5" x 5" area of the
open screen mesh. When the leg is flipped back the screen comes down and you grab
your rubber and wood handled squeegee and with the ink in front of your rubber squeegee
pull toward you applying pressure so ink will go through screen, once you have passed by
the 5" x 5" area then flip the screen back up and reverse squeegee to flood the screen for
the next print


Cadmium Sulphide ( CdS )

Crystal properties
Crystal growth method : Seeded vapor phase growth
Crystal growth orientation: (0001)
Maximum size: Up to 50mm diameter
Variations: Doped crystals (on request)


Crystallographic properties

Crystallographic structure: Hexagonal
a= 0.4135nm, c= 0.6749nm

Defects structure: Inclusions with < lOu. in size
Color: Red


Physical properties

Density: > 4.82 g/cm3
Melting point: > 1748 °C
Hardness: > 4 Mohs
Thermal conductivity: > 15.9 W m -1 K-1
Dielectric constant: > 8.28 C, 8.64 | I C
Band gap > (@ 300 K ): 2.53 eV
Specific resistivity: > ~108 (Ohms cm)
Emmission wavelength: > 600 nm @ 300 °K

Optical properties

Transmission range: >>>>>> 0.5 um -15 urn (2mm thick)
Refraction index:>>>>>>>> No = 2.517, Ne = 2.548