Solar power is inefficient. Whenever those plains of panels are laid out, the sunlight they convert into stored energy also degrades their effectiveness. With each day the panels spend smoldering under the sun, they become more unreliable in harvesting the rays. For many new systems, designed for lower cost and flexibility, degradation is a huge issue: In just 60 hours, efficiency can sometimes plummet as much as 90%.
To fix that problem, researchers from MIT turned to some excellent harvesters of sunlight for inspiration: plants. Chemical engineering professor Michael Strano recently had a eureka-moment while reading about plant biology. “I was really impressed by how plant cells have this extremely efficient repair mechanism,” he told MITNews. To mimic this process, his team began work on a set of self-repairing molecules, called phospholipids, that can turn sunlight into energy, and reassemble even after being broken down. By adding or removing a solution, the phospholipids create a structural support that responds to light and can realign the system once electrons are “knocked loose” by the particles of light.
With a grant from the MIT Energy Initiative, Strano built and tested a prototype of the synthetic molecules, discovering the system to be 40% efficient–about double the efficiency of the most advanced solar cells currently available. In one 14-hour trial, the cells were repeatedly assembled and disassembled, with no efficiency lost.
Strano also said the new “photovoltaic” technology could one day near
100% efficiency, and in the meantime, his team is working toward increasing the amount of electricity the cells can produce.
“We’re basically imitating tricks that nature has discovered over millions of years,” Strano explained.
[Photos by Patrick Gillooly]