Nanograss To Harvest Solar Cells Unveiled

Blades of grass are one of nature's most efficient light-harvesting structures.

Using bio-mimicry, an international team of researchers from the University of Massachusetts at Amherst, Stanford University and Dresden University of Technology in Germany, have developed a synthetic equivalent to grass to harvest energy in solar cells.

Led by polymer chemist Alejandro Briseno of UMass Amherst, the team has taken a major step in developing a polymer architecture to boost power-conversion efficiency of light to electricity for use in electronic devices, reports Science Newsline.

"Though it was difficult, we managed to get the necessary compounds to stack like coins," said Briseno. "Stacked compounds are ideal because electrons flow faster in a particular direction due to close molecule-molecule interactions."

The result was nanopillars or nanograss, which are nanoscale, engineered surfaces.

"The biggest challenge in producing this architecture was finding the appropriate substrate that would enable the molecules to stack vertically," noted Briseno. "We had exploited essentially every substrate possible until we finally succeeded with graphene. Using a scanning electron microscope they discovered little crystals standing upright."

"Our systems share similar attributes of grass such as high density array system, vertical orientations and the ability to efficiently convert light into energy," said Briseno.

"This work is a major advancement in the field of organic solar cells because we have developed what the field considers the 'Holy Grail' architecture for harvesting light and converting it to electricity," said Briseno. "The breakthrough in morphology control should have widespread use in solar cells, batteries and vertical transistors."

"The technique is simple, inexpensive and uses compounds that are commercially available," notes Briseno. "We envision that our nanograss solar cells will appeal to low-end energy applications such as gadgets, toys, sensors and short lifetime disposable devices."

The research was published in the journal Nano Letters.