Engineering news
The team from Stanford University in California looked at insect eyes during their work creating advanced new solar panels. The compound, honeycomb-style eyes provided the inspiration needed to practically use perovskite, a promising, low-cost photovoltaic material.
Despite converting solar energy to electricity as efficiently as silicon, perovskite is “extremely unstable and mechanically fragile,” said senior author Reinhold Dauskardt. Parts made with the material “would barely survive the manufacturing process, let alone be durable long-term in the environment,” he added.
The material has similar mechanical properties to table salt, said co-lead author Nicholas Rolston, who said it is the most fragile ever tested in the lab.
Undeterred by the challenges, the team was determined to exploit perovskite’s efficiency and low cost. To improve its durability, they turned to nature.
“We were inspired by the compound eye of the fly, which consists of hundreds of tiny segmented eyes,” explained Dauskardt. “It has a beautiful honeycomb shape with built-in redundancy: If you lose one segment, hundreds of others will operate. Each segment is very fragile, but it's shielded by a scaffold wall around it.”
Using a compound eye as a model, the team created a compound solar cell of 0.5mm perovskite “microcells” encapsulated in a hexagon-shaped scaffold of epoxy resin. The scaffold gave a “huge increase” in durability with no impact on efficiency, the team said.
The researchers also tested the cells at temperatures of 85°C and 85% relative humidity for six weeks to assess their potential application in real-world environments. The cells continued to generate electricity at high rates of efficiency, the team claimed.
“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.”
The research was published in Energy & Environmental Science.