When it comes to solar cells, less is more—the less their surfaces reflect a sun’s rays, the more energy can be generated. A typical fix to the problem of reflectivity is an anti-reflective coating, but that might not always be the best solution, depending on the application.
Lawrence Livermore National Laboratory (LLNL) researchers have come up with guidelines for an alternative to anti-reflective coatings on optical devices such as solar cells, glasses and cameras, finding that reflectivity of silicon optics can be reduced to as little as 1 percent by engineering their surfaces with layers of hierarchical micro- and nanometer length structures.
A team of LLNL researchers, led by chemical engineer Anna Hiszpanski and UC Santa Cruz graduate student Juan Diaz Leon, described the parameters in a recent paper published by the journal Advanced Optical Materials . The technology has its roots in nature, mimicking the hierarchical structures found in the eye of a moth, allowing them to absorb more light and better navigate in darkness.
“It’s a different anti-reflective approach,” said Hiszpanski, who performed the experiments and was the co-lead author on the paper. “The design rules for these hierarchical anti-reflective structures haven’t been explicitly laid out in these size scales. I’m hopeful they will enable others to more quickly design and fabricate optimal structures with the anti-reflective properties needed by their applications.”