The science behind it is as follows ...
The semiconductor chosen to absorb photons as electrons is wavelength sensitive and therefore will only absorb one of the colors of the rainbow and convert the photons to electrons ergo ... energy.
A 3D array with multiple semiconductor materials will capture more than one wavelength in a fixed geometric area and therefore convert more photons into electrons.
The really big breakthrough will be when they discover a semiconductor material that can absorb the infrared portions of the spectrum and convert them to energy.
The other bottle neck in this system is the conductors. Until now, the conductors have been lost space where photons are not allowed to be absorbed or passed thru to be collected later. A completely transparent conductor will greatly enhance the efficiency of photo-voltaic systems.
I love this stuff.