We present a wave theory for light trapping design in solar cells. The theory illustrates many of the optical design consideration in nanophotonic solar cell structures. In particular, we show how one can understand the 4n^2 limit from a mode counting perspective, and we develop ways to significantly overcome such a limit. We also show that there is an angular sum rule, which relates the angular integration of the light trapping enhancement factor, to the density of states of the system. Article not available.

© 2011 Optical Society of America