● Photons from the sun strike the cell with a certain amount of energy, releasing an electron.
● To create electricity, the electron needs to cross the gap, called band gap, between the two semiconductors.
● Only photons whose energy is equal to or greater than the band gap of the cell material can give off energy.
● The released electron flows through the circuit, creating an electrical current (DC).
● The electron then comes back into the cell and becomes a part of the system again.

● US is fourth largest market in PV installations
● Cheaper to mass produce solar panels o Economies of scale (lab 1”x1”, 50-
100mW, around $50-$100) o 33% decrease in average prices from
2011 to 2014
 new materials
 advanced technology
 trained and experienced installers
○ Lower efficiency

● 3/4 of Americans support solar development; bipartisan support
● Solar subsidies substantial but set to decline o 30% Project cost subsidy 10% in 2016 o MACRS
● Challenges: o Utility Company/Grid Limits
 Limitations for grid stability
 Legal process for installation o Intermittence/Storage
 Operate ~5 hrs/day
 Storage technology in infancy

Pros
● Renewable
● Abundant
● Low Maintenance
● Silent
● Safe
● Environmentally Friendly
Cons
● Expensive
● Intermittent
● Energy Storage
● Exotic Materials
● Large Space Requirement
● Increased grid electric cost
● Fewer job opportunities
● Warming micro-environment..

Solar Energy Group at Purdue with Dr. Agrawal
● Research on cutting-edge photovoltaic cells that are more efficient and have lower costs
● Printing and applying these to everyday use

●
Goal - Create a solar panel using: o Glass substrate o Titanium dioxide (TiO
2
) Semiconductor o Blackberry/Raspberry Juice Dye o Graphite pencil o KI Electrolyte
● Testing o Determined our panel efficiency using
Scott’s “synthetic sun”
● Results o Highest efficiency: 0.147% o Average market panel efficiency: 11-15% o Goal for Dr. Agrawal’s laboratory: 15%
Dye
Electrolyte
Semiconductor
To circuit

● Currently only 0.5% of US energy production
● Limited by light availability, price, and storage capacity
● Much “cleaner” than popular energy production methods (coal)
● Panels are expensive but declining in price
● Energy storage is inadequate but improving
● Potential in both residential and industrial power generation
● Poised to provide a large slice of future American and worldwide electricity
GO PURDUE

● http://science.nasa.gov/science-news/science-at-nasa/2002/solarcells/
● http://www.gallup.com/poll/161519/americans-emphasis-solar-wind-natural-gas.aspx
● http://www.pveducation.org/pvcdrom/pn-junction/band-gap
● http://www.ucsusa.org/clean_energy/our-energy-choices/renewable-energy/solar-power-technologiesand-policies.html#.VYiekPlViko
● http://www.sunlightelectric.com/subsidies.php
● http://www.eia.gov/beta/MER/index.cfm?tbl=T10.01#/?f=M&start=200001
● http://science.nasa.gov/science-news/science-at-nasa/2002/solarcells/
● http://energyinformative.org/solar-energy-pros-and-cons/
● http://tipmont.org/solar
● http://www.seia.org/policy/finance-tax/third-party-financing
● http://energyinformative.org/solar-panels-cost/
● http://solarprofessional.com/articles/design-installation/nec-section-70512-and-utility-interconnections
● https://engineering.purdue.edu/Solar/
● http://www.pveducation.org/pvcdrom/design/efficiency-and-cost
● http://www.seia.org/policy/solar-technology/photovoltaic-solar-electric