If you ever wondered how solar cells could repair themselves when their performance degrades, just look at the back of your hand or the closest leaf of a plant.
Branching vascular channels which pass life-sustaining nutrients through our bodies and plant’s leaves were the inspiration for solar cells that can restore themselves economically and efficiently. Researchers from North Carolina State University recently showed that making solar cells with channels that imitate organic vascular systems can revive solar cells whose performance deteriorates due to degradation by the sun’s ultraviolet rays. Solar cells that are based on organic systems hold the possibility of being less expensive and more environmentally friendly than the current industry standard silicon-based photovoltaic cells.
Dye Sensitized Solar Cells
These organically inspired devices are a form of dye-sensitized solar cell, consisting of a water-based gel core, electrodes, and inexpensive, light-sensitive, organic dye molecules that capture light and generate electric current. Dye molecules that get “excited” by the sun’s rays to produce electricity eventually degrade and lose efficiency, says researcher Orlin Velev. They need replenishing in order to restore the device’s effectiveness in harnessing solar power.
Stable long term solar power farms will need to be less maintenance intensive for wide-spread adoption. The washing activation cycle demonstrated in this work allows reliable replacement of the organic component in a dye-sensitized photovoltaic system.
Nature Knows Best
“Organic material in DSSCs tends to degrade, so we looked to nature to solve the problem,” Velev said. “We considered how the branched network in a leaf maintains water and nutrient levels throughout the leaf. Our microchannel solar cell design works in a similar way. Photovoltaic cells rendered ineffective by high intensities of ultraviolet rays were regenerated by pumping fresh dye into the channels while cycling the exhausted dye out of the cell. This process restores the device’s effectiveness in producing electricity over multiple cycles.”
Velev, lead author of a paper describing the research, goes on to say that the new gel-microfluidic cell design was compared to alternate designs, and that branched channel networks similar to the ones found in nature worked best.