Graphene-based Solar Cells May Seek Scarce Venture Funding.Friday, 23 April 2010 12:11 Phoenix Green Business Examiner .0Numerous universities across the U.S. are investigating ways to improve the efficiency and light capture abilities of solar cells.
A new category of solar technology was established in the last decade denoted as third generation solar cells, which applies to the family of materials including nanostructures such as: three-dimensional pillars, wires, quantum dots (Solterra in Tempe, AZ), and glitter-like crystals. First and second generation solar cells deal with more well-developed materials such as crystalline and amorphous silicon, respectively, and have been implemented into commercial applications, whereas nanostructures are still in the R&D phase in labs and start-up company facilities.
A team of chemists at Indiana University Bloomington has incorporated large sheets of carbon to enhance light collection in advanced solar cells. This new design includes a three-dimensional bramble patch on each side of the carbon sheet. Using this method, the group was able to dissolve sheets containing as many as 168 carbon atoms, which is considered a major accomplishment in the field.
The main interest is derived from the drive to find a naturally abundant material that can efficiently absorb sunlight. Carbon meets this requirement and is inexpensive, while the graphene form of this material, which is essentially one atom thick, is capable of absorbing a wide range of light frequencies compared to semiconductors, which typically need to be layered together for this purpose. Graphene shows promise as an effective, relatively inexpensive, and less toxic alternative to other materials currently used in solar cells. Other 3rd generation solar cells are utilizing silicon nanowires for improving light capture efficiency, as silicon is readily available in nature but typically more costly than this form of carbon.
There are some complications in utilizing graphene in this application. Large graphene sheets are attracted to each other and tend to glom onto each other; thus, this materials integration issue needed to be addressed. The Indiana University research group evaluated a solution that attached a semi-rigid, semi-flexible, three-dimensional hexagonal carbon ring and three long, barbed tails made of carbon and hydrogen to the sides of the graphene, which kept sheets as large as 168 carbon atoms from adhering to one another. Using this method, they could make the graphene sheets from smaller molecules so that they are uniform in size. What’s more, there is additional interest in replacing silicon substrates in the microchip industry with graphene due to its superior charge transport properties. More details on the graphene-based solar cell research will appear in a future issue of Nano Letters.
In terms of taking university innovation to commercialization, funding has improved slightly over the course of the year; however, only 32 venture funds in the U.S. supported new entrepreneurial endeavors in 2010 thus far, according to a report by Thomson Reuters and the National Venture Capital Association. The first three months of this year marked the slowest opening quarter of activity since 1993. Furthermore, the $3.6 billion raised for new funds was down 31 per cent from the same time last year, and the 32 active funds indicated a 44 per cent decline in the total number of firms in this space.
Part of the slowdown in funding start-ups in the clean energy sector has been the lack of formerly anticipated comprehensive energy reform on Capitol Hill, even though the fossil fuel industry has faced several recent tragedies in deadly coal mine explosions and off-shore oil platform fires. Phoenix, Arizona is home to several alternative energy start-up companies seeking venture capital funding as well.
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