There is apparently a "light-self-induced pyroelectric effect" which can partially explain what is going on in the UltraSolar device, assuming it is really more than ghostware.
The Nature article below is about UV sensors instead of solar cells, but there could be a common denominator which explains why a pyroelectric effect works in this situation. http://www.nature.com/ncomms/2015/150925/ncomms9401/abs/ncomms9401.html Most conventional solar cells use the visible and infrared light spectrum to generate electricity and miss some of the more energetic UV photons. This may or may not be related to dark current but of course UV is "blacklight" and it is probably not a coincidence that UV specific photocells have little or no dark current. Anyway - the common sense approach to provide good evidence of whether or not UltraSolar really has something is this. Apple Computer has built a new campus within walking distance of the UltraSolar headquarters. The so-called "Spaceship campus" in Cupertino includes a roof made almost entirely out of solar cells - which is at least a 5MW installation. If all Apple needs to do is buy the booster box to get another megawatt it is almost a certainty that they would do this, as cost is no impediment. Yet I can find no indication that they have bought into this technology. It would be the best PR in the world for UltraSolar if they did supply Apple -- and the lack of this partnership is very "telling" shall we say.
