Sunday, July 25, 2010

Graphine Organic Photovoltaic : A possible substitute for the silicone solar cells

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A flow of methane and hydrogen gas mixture deposits carbon atoms as graphene on a nickel plate. The graphene later is then transferred to a plastic sheet, which is then incorporated into an organic photo voltaic (OPV) cell.

a monocrystalline silicon wafer based solar cell

Energy crisis is the one of the major problems which is giving some really horrifying nightmares for the human race today...!!! So scientists all around the globe have been trying their best to tackle the this situation from a long time and come up with solar power as an answer.

Currently to tap the solar power the most efficient method i.e, using the monocrystalline silicon wafer based solar cells.They convert the sun light directly into electricity by the photovoltaic effect . But the main drawback of this solar cells is that they are not costly.

A large body of research is being done all over the world to manufacture silicon wafer-based solar cells at lower cost and to increase the conversion efficiencies without an exorbitant increase in production cost. The ultimate goal for both wafer-based and alternative photovoltaic concepts is to produce solar electricity at a cost comparable to currently market-dominant coal, natural gas, and nuclear power in order to make it the leading primary energy source. To achieve this it may be necessary to reduce the cost of installed solar systems from currently about US$ 1.80 (for bulk Si technologies) to about US$ 0.50 per Watt peak power.

As a possible solution for this problem A University of California team has produced flexible transparent carbon atom films that the researchers say have great potential for a new breed of solar cells
Zhou and the other researchers on the USC team -- which included Yi Zhang, Cody W. Schlenker, Koungmin Ryu, and Mark E. Thompson in addition to Gomez de Arco have recently published a paper in the journal ACS Nano in which they have stated as"Organic photovoltaic (OPV) cells have been proposed as a means to achieve low cost energy due to their ease of manufacture, light weight, and compatibility with flexible substrates,"
The main critical aspect of OPV photovoltaic cell is that it does not uses silicon but graphene, a highly conductive and highly transparent form of carbon made up of atoms-thick sheets of carbon atoms.To manufacture such sheets a process called chemical vapour deposition is used.
In this process, the USC engineering team creates ultra thin graphene sheets by first depositing carbon atoms in the form of graphene films on a nickel plate from methane gas.

Then they lay down a protective layer of thermo plastic over the graphene layer, and then dissolve the nickel underneath in an acid bath. In the final step they attach the plastic-protected graphene to a very flexible polymer sheet, which can then be incorporated into a OPV cell.

But unfortunately such OPV cell are not as efficient as silicon cells."For every 1000 watts of sunlight that hits a one square meter area of the standard silicon solar cell, 14 watts of electricity will be generated," says Lewis Gomez De Arco, a doctoral student and a member of the team."Organic solar cells are less efficient; their conversion rate for that same one thousand watts of sunlight in the graphene-based solar cell would be only 1.3 watts."

Beside their low efficiency by looking on the bright side these OVPs can potentially more than make for in lower price and, greater physical flexibility.
"They could be hung as curtains in homes or even made into fabric and be worn as power generating clothing. I can imagine people powering their cellular phone or music/video device while jogging in the sun," say Acro.

So lets hope this really substitutes the silicon and let it make the humans sleep without the 'nightmares'.....!!

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