NETANYA, Israel Scientists at the University of Tel Aviv in Israel claim they have found a way to construct efficient photovoltaic cells costing at least a hundred times less than conventional silicon based devices, and with similar or better energy conversion efficiency.
The reactive element in the researchers' patent pending device is genetically engineered proteins using photosynthesis for production of electrical energy.
The scientists applied genetic engineering and nanotechnology for the construction of a hybrid nano -- bio, solid state device. According to the researchers, although using photosynthesis for photovoltaic application is not new, their specific technique is the first to enable the production of useful photosynthesis-based photovoltaic cells.
The Israeli team is set to challenge others who are using photosynthesis for photovoltaic cells, including universities such as Cambridge in the U.K., and Stanford, M.I.T, the U.S. Naval Research Laboratory, and the Universities of Tennessee and Arizona in the U.S, and several others.
The researchers suggest existing silicon based photovoltaic cells offer low average energy conversion efficiency of 12-14 percent, while their system is capable of efficiencies of about 25 percent. They based their photovoltaic device on genetically engineered dry proteins photosystem I (PS I), encapsulated in solid state substrate bottom metal and a top transparent electrode.
They also claim that PS I generates a stable charge separation in 200 ns across 6 nm of protein to generate an electric potential of 1 V with quantum efficiency of 1 and absorbed energy conversion efficiency of 47 percent. A further advantage of PS I is said to be its transparency to infrared radiation, which eliminates the need for expensive cooling equipment.
The researchers include Prof. Chanoch Carmeli, Dr. Shachar Richter, Dr. Itai Carmeli and Prof. Yossi Rosenwaks. Ramot, Tel Aviv University’s technology transfer company, is set to help commercialize the invention.
Larry Loev, director of business development for high technologies at Ramot told EETimes the low cost of the proposed device is based on the low cost of PS I in comparison to silicon. While one square meter of PS I should cost around $1, a similar area made of silicon should cost around $200.
"We connected our device to electrodes and we saw how it converts light to electricity," said Loev.
EETimes Europe has learned that Ramot will probably use the industrial facilities of solar energy specialist Millennium Electric T.O.U Ltd. (Ra’anana, Israel) for making prototype devices, including engineering of the prototype up scaling, automation of production and the integration of the university's photovoltaic cell with other components in the final device. Ramot aims to develop a cost effective device of 10mm X 10mm in size within three years.
Asked about the competition, Loev claimed: "Certainly many researchers are looking into how to use photosynthesis to create photovoltaic cells. However, a deeper look at what has been published shows major differences between what our group has achieved and the rest. First, ours is the only group to utilize an organic material in a dry and stable environment.
"Other groups have only done this under aqueous conditions which are much less robust. Second, we are able to directly metallize the protein and make good electronic coupling to the electrodes. Other groups have utilized intermediate polymers for this purpose, which is a very complicated procedure. Third, we have demonstrated multilayer capability, which is crucial to getting good efficiency."