Thinking Three Dimensional With Photovoltaics

It's sort of amazing how long photovoltaic (PV) technology has been around. It seems like only yesterday that Alexandre Edmond Becquerel was experimenting with metal electrodes in an electrolyte and discovered the photovoltaic effect.
Well, since 1839, things have changed—mostly for the better. There have been many variations on this fairly simple initial concept, and as the technology moves forward, there has been a struggle to build thinner and thinner cells, which is closely related to the pursuit of cost reduction.
This frugality of space and materials is in the interest of shaving off a few cents per watt produced—or put another way, the generated power to material ratio needs to be optimal so that producing these cells can become cost competitive with other technologies.
The most efficient design has long been the flat thin solar cell, but a few researchers—Bryan Myers, UC Berkeley, Marco Bernardi, MIT, and Jeffrey C. Grossman, MIT—have presented the concept of a three-dimensional photovoltaic (3DPV) cell. In this Applied Physics Letters article, they ask take a look at optimizing the geometry of 3DPV's.
The authors conclude that these 3DPV's can "substantially more energy in a day than flat panels of the same area footprint..."