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PHOTOVOLTAIC CELLS
Parth Bhide
SUMMER RESEARCH
 What
is a Photovoltaic Cell?
 How do Photovoltaic Cells Work?
 Why are Photovoltaic Cells not 100%
Efficient?
 What Technologies and Materials Help
Boost the Efficiency of Photovoltaic Cells.
 The Use of Nanotechnology
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WHAT IS A PHOTOVOLTAIC CELL?
A
photovoltaic (PV) cell.
Uses energy in photons
(solar energy) and
converts it to electricity.
 Most PV cells contain
the semiconductor
silicon.
 The silicon found in PV
cells is unpurified
(doped) with boron and
phosphorous using an
ion implanter.
http://www.petervaldivia.com/technology/projects/helicopter/images/
HOW DO PHOTOVOLTAIC CELLS
WORK?


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http://sustainableenergysystemz.com/wp-content/uploads
The silicon doped with
phosphorous creates a
negative charge (n-layer),
and the silicon doped
with boron creates a
positive charge (p-layer).
The junction between the
layers allows for the
passage of electrons from
the n-layer to the p-layer.
As photons excite
electrons, the electrons
move from the n-layer to
the p-layer, through a
separate wire, creating
electricity.
WHY ARE PHOTOVOLTAIC CELLS NOT 100%
EFFICIENT?

The efficiency of PV cells depends
on many factors.
 Band Gap- The amount of
energy needed to break electrons
from their atoms.
 Impurity Ratio- To prevent
recombination of electrons into
other nuclei.
 The reflection of light off the
silicon cells.
http://www.petervaldivia.com/technology/projects/helicopter
WHAT TECHNOLOGIES AND MATERIALS
HELP BOOST THE EFFICIENCY OF
PHOTOVOLTAIC CELLS.
To widen the band gap range,
research is being done to use
different materials and
combinations of ions to increase
the usable energies of photons.
 With the challenge of new
materials comes the challenge
of maintaining basic particle
and chemical interaction.
 Layers of antireflective
materials to prevent the
reflection of incoming photons

http://pveducation.org/pvcdrom/design/anti-reflection-coatings
THE USE OF NANOTECHNOLOGY
 Nanotechnology
is being
developed in photovoltaic
advancement

http://en.wikipedia.org/wiki/Black_silicon


Nano-sized holes, smaller
than photons used to
keep light from being
reflected.
Odd geometry and small
100-nm holes to increase
the anti-reflectivity.
Underdeveloped
technologies, including a
paint that acts as a solar
cell.
MY SUMMER

My mom and I went to visit our relatives and go
sightseeing in India.
CONCLUSION
Photovoltaic cells convert solar energy into
electrical energy.
 Although complex, PV cells remain
approximately 20% efficient and very expensive.
 Different materials and structures can influence
the efficiency of the cell.
 Several factors that need to be improved are
antireflectivity, compositional uniformity, and
band gap of the material.

REFERENCES
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"How Solar Energy Works." Http://www.ucsusa.org/. Union of Concerned Scientists, n.d.
Web. <http://www.ucsusa.org/clean_energy/our-energy-choices/renewable-energy/how-solarenergy-works.html>.
Kiger, Patrick J. "Sun Plus Nanotechnology: Can Solar Energy Get Bigger by Thinking
Small?" National Geographic Daily News. National Geographic, n.d. Web. 2013.
<http://news.nationalgeographic.com/news/energy/2013/04/130429-nanotechnology-solarenergy-efficiency/>.
Knight, Matthew. "New Nano Coating Boosts Solar Efficiency." CNN. Cable News
Network, n.d. Web. 2013. <http://www.cnn.com/2008/TECH/science/11/06/solar.coating/>.
"Photovoltaic Cell Conversion Efficiency." Eere.energy.gov. United States Department of
Energy, n.d. Web.
<http://www.eere.energy.gov/basics/renewable_energy/pv_cell_conversion_efficiency.html>.
Preuss, Paul. "A Step Closer to the Optimum Solar Cell." A Step Closer to the Optimum
Solar Cell. Science Beat, n.d. Web. 2013. <http://www.lbl.gov/Science-Articles/Archive/sbMSD-multibandsolar-panels.html>.
Rubin, Leonard, and John Poate. "Ion Implantation in Silicon Technology - The Industrial
Physicist." Ion Implantation in Silicon Technology - The Industrial Physicist. The
Industrial Physisist, n.d. Web. 2013. <http://www.aip.org/tip/INPHFA/vol-9/iss3/p12.html>.
"Types of Silicon Used in Photovoltaics." Energy Basics:. US Department of Energy, n.d.
Web. 2013. <http://www.eere.energy.gov/basics/renewable_energy/types_silicon.html>.
QUESTIONS?
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