Moth eyes were last year’s big thing in solar cell biomimicry, and now it looks like a new challenger has stepped into the ring. A research team from Germany’s Karlsruher Institut für Technologie has zeroed in on the nanoscale structure of rose petals — specifically, the El Toro variety — to improve thin-film solar cell efficiency by up to 13%. If the name El Toro doesn’t ring a bell, our friends over at the UC–Davis…