An assortment of links to interesting information  

Semiconductor Nanowires Could Double the Efficiency of Silicon Solar Cells

A p/n semiconductor junction is not the only way of converting sunshine into useful electrical energy.  Light consists of a flow of photons of various energy levels (colors).  See this article-Solar Cells.  Nanowires on the solar cell surface can also convert sunshine into useful electrical energy.  This works because photons also have a wave function that can be harnessed. See this interesting article:Semiconductor Nanowires Could Double the Efficiency of Si Solar Cells