In the future, solar cells and LED displays could be designed to mimic nature’s own solar panel – the leaf. A research team from the Leibniz Institute of Photonic Technology (IPHT) in Jena, has succeeded in building electrodes with excellent optical and electronic properties from the leaves of the purple Magnolia. When the leaf veins were coated in copper, the skeletons were turned into transparent, fully conductive electrodes.

“We took our inspiration from nature's perfectly ingenious system to construct electrodes with a high power density and low material consumption," reports Dr Guobin Jia from Leibniz IPHT, the first author of the study published in the journal Nano-Micro Letters.

Plant leaves convert water and CO2 into sugars and oxygen through the process of photosynthesis via a highly-efficient network of veins. “Thus, they have much in common with the electrodes in solar cells, batteries or LEDs that collect or distribute electrical current or signals," explains Dr Jonathan Plentz, who heads up the Photonic Thin Film Systems working group at Leibniz IPHT.

The webbed structure has a major advantage over modular solar cells – if part of the leaf is damaged, the system remains fully functional. Furthermore, the “sheet resistance” is two orders of magnitude lower than the conventional ITO (indium tin oxide) thin films used for the electrodes in solar cells and touch screens, which means the electrical performance is correlatively better. The leaf-inspired sheet electrodes also proved to be superior in terms of optical transmission of UV and infrared spectrum.

“If we were able to better understand the excellent distribution and transport function of leaf veins with the help of a mathematical model, this could help to improve completely different transport processes that run in two directions," explains Jia, and even feed into grid architecture, fibre optic design and town planning.