by Although plants serve as a source of nutrients, oxygen, and decor, they are not generally considered a good source of electricity. But scientists can generate electricity as part of a “green” biological solar cell by harvesting the naturally transported electrons in plant cells. Now, researchers reporting ACS Applied Materials and Interfaces they used a succulent plant for the first time to create a living “bio-solar cell” powered by photosynthesis.
In all living cells, from bacteria and fungi to plants and animals, electrons shuttle through as part of natural, biochemical processes. But if electrodes are present, the cells can actually generate electricity that can be used externally. Earlier researchers had created fuel cells this way with bacteria, but the microbes had to be fed constantly. Instead, scientists including Noam Adir’s team turned to photosynthesis to generate current. During this process, light diverts a flow of electrons from the water, which ultimately results in the formation of oxygen and sugar. This means that living photosynthetic cells constantly produce a stream of electrons that can be drawn as a “photocurrent” and used to power an external circuit, just like a solar cell.
Some plants, such as succulents found in arid environments, have thick cuticles to retain water and nutrients in their leaves. Yaniv Shlosberg, Gadi Schuster and Adir wanted to test for the first time whether photosynthesis in succulents could generate power for living solar cells by using the internal water and nutrients of an electrochemical cell as the electrolyte solution.
Researchers have created a living solar cell using succulent. Corpuscularia lehmannii, also called “ice plant”. They placed an iron anode and a platinum cathode in one of the leaves of the plant and found that its voltage was 0.28 V. Produces up to 20 µA/cm when connected to a circuit2 photocurrent density when exposed to light and can continue to produce current for more than one day. While these numbers are less than for a conventional alkaline battery, they only represent a single leaf. Previous research on similar organic devices suggests that connecting multiple sheets in series can increase the voltage. The team specially designed the living solar cell so that the protons in the inner leaf solution could combine to form hydrogen gas at the cathode, and that hydrogen could be collected and used in other applications. The researchers say their method could enable the development of future sustainable, multifunctional green energy technologies.
The authors acknowledge support from a “Nevet” grant from the Grand Technion Energy Program (GTEP) and the Technion VPR Berman Energy Research Grant and Technion’s Hydrogen Technologies Research Laboratory (HTRL).
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