Black butterfly wings inspire new solar cell
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The wings of the black butterfly, a species native to Asia, inspired a scientific team that, reproducing its architecture, designed thin photovoltaic cells that could improve the absorption capacity of these systems by up to 200%.

The investigation, responsible for California Institute of Technology and German Institute of Technology Karlsruhe, opens the door to a significant improvement in thin-film solar technology which, therefore, could outperform conventional panels in terms of efficiency.

To achieve this progress, the results of which have just been published in Scientific progress, the research started from the study of the Pachliopta aristolochiae or black butterfly. The fact that this species needs light to fly has led to some unique wings that absorb sunlight. But not only that, but it achieves it in a very wide range both in spectrum and in angle.

This quality, transferred to solar technology, makes it possible, for example, to maintain absorption even when the light has no direct impact on the cell. Hence, in fact, the results collected by this team. As he concludes in his study, with these cells absorption improves between 90% and 200%, depending on the angle of incidence of the light.

To get there, the work started much earlier. He did this, at first, with a careful study of butterfly wings under a microscope. At this point it was found that the wings were completely covered with ridges and small holes. It is this structure that allows these Lepidoptera to absorb light in an exceptional way.

With this information, the scientific team designed photovoltaic absorbers inspired by the natural structure of nano-holes. Made from hydrogenated amorphous silicon, these models combined the lightness, strength and light-catching properties that had been observed in butterfly wings.

The results obtained in terms of absorption show the strength of this innovation which, however, still has a long way to go. “We know that we can further improve the coupling properties and absorption capacity of the design, by optimizing the etch profile.”, assure the promoters of the study who, however, do not doubt its potential. “The substantial improvement in the optical performance of these structures and the possibility of scaling them up position this research path as promising candidate for future photovoltaic applicationsThey add a scientific breakthrough which, again, has its inspiration in nature.