With a new generation of photovoltaics called “perovskites” that produce more efficiently but aren’t very durable, Stanford researchers are taking inspiration from the micro-lenses of fly eyes.

Perovskite deteriorates when exposed to heat or mechanical stress, which are two things common for a rooftop solar array to deal with. The Stanford team conducted a study using the inset design as a protectant for the fragile cells. Senior author of the study, Reinhold Dauskardt, stated, “Perovskites are promising, low-cost materials that convert sunlight to electricity as efficiently as conventional solar cells made of silicon. The problem is that perovskites are extremely unstable and mechanically fragile. They would barely survive the manufacturing process, let alone be durable long term in the environment.”

Graduate student Nicholas Rolston called perovskites the “most fragile material ever tested” in their laboratories. To deal with this, they looked to the honeycomb nature of a fly’s eye and created a hexagon-shaped scaffold to encompass the microcells, made from an expoxy resin that is resilient to mechanical stresses.

To test its heat durability, researchers exposed the cells to 185 degrees at 85% relative humidity for six weeks and even in these extreme conditions the cells continued to work very efficiently.

“We are very excited about these results,” said Dauskardt. “It’s a new way of thinking about designing solar cells. These scaffold cells also look really cool, so there are some interesting aesthetic possibilities for real-world applications.”