There's an abundence of sites that explain solar energy in-depth and it can be hard to wade through them all. There are a few sites that are especially helpful and are the best place to start for more information.

Solar Energy Industries Association: SEIA offers an indsutry-insider view of the growth of solar energy and was recommened as a source by Patrick Seehan of Florida's Office of Energy.

U.S. Department of Energy: For detailed information, including charts and reports of solar use and growth, and advice for average consumers who want to begin using solar energy.

U.S. Energy Information Administration: A wealth of information, including annual reports and forecasts, that cover things energy are available through the EIA.

EIA 2013 Report: The 2013 report offers the most complete and up-to-date information on energy in the United States.

Wikipedia: While some teachers may still not approve of using Wikipedia as a source, the article on solar cells is ripe with good, detailed information and links to additional sources.

To further my own knowledge prior to making this site, I have also interviewed the following people:

Dustin Stephany, master's student working in in the energy department of the University of Florida’s Physical Plant Division
Jason Gonos, Director of Power Production Management, Inc.
Patrick Seehan, Director of the Office of Energy, under Florida Department of Agriculture and Consumer Service