You don't have to know Shel Silverstein to know that trees are exceptionally giving. They're responsible for our homes, paper, air, furniture and, now, energy -- the "clean" kind, that is. Researchers from the Georgia Institute of Technology and Purdue University have jointly devised a patent-pending method to build organic solar cells using plant-derived substrates. Known as cellulose nanocrystal substrates (or CNC), these solar cells benefit from bei
