pv panels

PV Panels

Nate Trachimowicz

And

Evan Graves

How panels work

Silicon is doped with different chemicals Providing the desired properties of the resulting

compounds Based on valence electrons

One compound or side, is made to be electro-negative (N-type)

The other side, being electro-positive (P-type)

N-type

P-type

N-Type:

Semiconductors with an excess of electrons

P-Type:

Semiconductors with an absence of electrons

The Electrons(remember having 4, is stable)

Making Electron Pairs

Load

N-side

“Extra”

P-side

“Holes”

Light Band Gap Electricity Each element has a band gap:

The difference in energy between the valence band (electron bound to an atom) and the conduction band (electron free to move between atoms).

Measured in electron volts, eV Metals have a low band gap,

electrons flow easy Each wavelength of light has an associated energy

Silicon band gap is 1.1 eV which peaks in the infrared region (980 nm )

Different elements and materials provide a spectrum of options to absorb the sun’s energy.

Thin-Film Materials for High Power-to-Weight-Ratio Space

Photovoltaic Arrays copper, indium, and sulfur, or copper, indium,

gallium, and selenium CuInSe2/CuInS2/CuGaSe2 Decomposition of single-source precursor to

produce CuInS2.

Higher efficiency tricks

The foundation of the new UNI-SOLAR PVL is the Triple Junction silicon solar cell unique to UNI-SOLAR .

Each cell is composed of three semiconductor junctions stacked on top of each other.

This spectrum splitting capabilityis the key to higher efficiency.

Higher efficiency tricks

When a photon excites an electron, or kicks it. It will probably fall back into orbit losing energy as

heat. This is known as recombination.

The trick to constructing high efficiency solar cells lies in minimizing recombination.

Price Comparison, thin film

Product Price $/W

Unisolar PVL-31T roof laminate 168.65 5.44

Unisolar PVL-116T roof laminate 597.89 5.15

Shell ST20 161.10 8.05

Shell ST40 214.44 5.36

Good sites

http://murray.newcastle.edu.au/users/students/2004/c2003616/intro.htm

http://www.webelements.com/webelements http://www.grc.nasa.gov/WWW/RT1999/5000/5410hepp.

html http://www.madsci.org/posts/archives/aug98/901775020.

Eg.r.html