MIT researchers create new self-assembling photovoltaic technology that repairs itself We're basically imitating tricks that nature has discovered over millions of years" in particular, "reversibility, the ability to break apart and reassemble," Strano says. The team, which included postdoctoral researcher Moon-Ho Ham and graduate student Ardemis Boghossian, came up with the system based on a theoretical analysis, but then decided to build a prototype cell to test it out. They ran the cell through repeated cycles of assembly and disassembly over a 14-hour period, with no loss of efficiency. Strano says that in devising novel systems for generating electricity from light, researchers don't often study how the systems change over time. For conventional silicon-based photovoltaic cells, there is little degradation, but with many new systems being developed either for lower cost, higher efficiency, flexibility or other improved characteristics the degradation can be very significant. "Often people see, over 60 hours, the efficiency falling to 10 percent of what you initially saw," he says. The individual reactions of these new molecular structures in converting sunlight are about 40 percent efficient, or about double the efficiency of today's best commercial solar cells. Theoretically, the efficiency of the structures could be close to 100 percent, he says. But in the initial work, the concentration of the structures in the solution was low, so the overall efficiency of the device the amount of electricity produced for a given surface area was very low. They are working now to find ways to greatly increase the concentration.