High performance solar cells: It's all about the optics(Conference Presentation)

For solar cells at 25%, good electron-hole transport is already a given. Further improvements of efficiency above 25% are all about the photon management! Our mantra is: "A good solar cell has to be a good LED; A great solar cell has to be a great LED! It has been found that thin-film cells are more efficient than the best wafer cells. Even more counter-intuitively, solar cells perform best when some of the solar photons are returned as external fluorescence. That is, the external luminescence yield ext, should be maximized. Good external fluorescence produces record output voltage.