In new work, reported in the October 16, 2012 online edition of Advanced Functional Materials (Nanoparticle Stacks with Graded Refractive Indices Enhance the Omnidirectional Light Harvesting of Solar Cells and the Light Extraction of Light-Emitting Diodes"), Chen and his team have not only demonstrated this advantageous feature but also provided a strategy for optimizing the types and sizes of na