Chemists Identify New Way to Create Photovoltaic Devices

Apr 01, 2010
UMass Amherst Chemists Identify an Exciting New Way to Create Photovoltaic Devices to Convert Solar Energy to Electricity
Photovoltaic device diagram

(PhysOrg.com) -- A promising new polymer-based method for creating photovoltaic devices, which convert sunlight into electricity, has been identified by chemists at the University of Massachusetts Amherst. Their new technique should lead to more efficient power production than achievable by the current generation of semiconductors.

The work by Sankaran Thayumanavan and colleagues at UMass Amherst, with others at the University of California-Riverside, is highlighted in the current issue of the (JACS), a premier chemistry journal, for the clever way it mimics nature’s way of harnessing solar energy.

To achieve the breakthrough, Thayumanavan and co-workers took inspiration from plants and experimented with organic molecules to mimic the photosynthetic machinery of plants. Their new paper demonstrates how a photosynthesis-style photovoltaic device can be designed using large, highly branched, non-biological called dendrimers, based on plant anatomy. Branches allow the dendrimer to absorb photons from a wide area and funnel this energy to the dendrimer’s core where it is connected to a polymer “wire.” At the core, charge is separated and the electrons travel down the polymer “wire” to an electrode where electricity is produced.

As Thayumanavan explains, “Our method is inspired by an energy-harnessing process that plants use in nature, which evolved over millions of years to be efficient in terms of capturing a lot of energy and transporting it short distances without power loss. In the future, photovoltaic devices may no longer rely on slower, less efficient human-made semiconductors. Our work should lead to lighter, more efficient and sustainable .” Thayumanavan, known to colleagues as “Thai,” is director of the UMass Amherst’s Fueling the Future Center for Chemical Innovation.

He adds, “The hope is that such a bio-inspired design could approach the conversion efficiency that plants achieve naturally.”

The recent JACS article by him and colleagues titled, “Dendritic and linear macromolecular architectures for photovoltaics: A photoinduced charge transfer investigation,” was selected by the journal editors to appear in a special section, “Harnessing Energy for a Sustainable World.” They predict that the research will transform the way engineers design future photovoltaic devices.

The editors add, “Innovation through scientific discovery is a necessary component of much societal advancement. To truly implement sustainable practices, energy must be harnessed more cleanly and stored for efficient distribution and use. This systems-level change sometimes referred to as the New Industrial Revolution, will require novel materials as well as savvy analysis and modeling to ensure success.”

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More information: Paper: pubs.acs.org/doi/full/10.1021/ja1017738

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User comments : 7

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Nemo
not rated yet Apr 01, 2010
I thought plants only converted solar energy at the rate of 1 or 2%..
Parsec
not rated yet Apr 01, 2010
The amount of energy it takes to build the entire complex plant requires solar efficiency in the range of 8-10%. However, burning it or harvesting its by products wastes a lot of that energy.

So the plant is converting at 10% (or so), then you can get about 10% of that energy back when you burn the plant (or use it for bio-fuel). Thats where the 1 to 2% figure your quoting comes from.
finfife
not rated yet Apr 01, 2010
"The hope is that such a bio-inspired design could approach the conversion efficiency that plants achieve naturally."

They're hoping to reach 3%-6% efficiency?

Man-made PV panels on the market already get 15-20%.

Maybe their approach could result in cheaper cells, but that's not what this article is claiming. It's all about how much more efficient they will be.

Am I missing something?

http://en.wikiped...ficiency
Parsec
not rated yet Apr 01, 2010
Man made PV panels are made from expensive stuff. If you could get 1/2 the efficiency from materials 1/10 as expensive and easy to make with green processes, I think you would come out ahead. Maybe.
fixer
not rated yet Apr 02, 2010
Price is all, as long as your roofs big enough!
DaveGee
not rated yet Apr 13, 2010
Like Einstein said... Everything is relative... A 10x cheaper but if they're only 1/2 the efficiency of traditional solar cells, it doesn't do you a whole lot of good if you have...

- A limited area to place them (think tightly pack city environment)
- Extremely expensive transportation costs (think space shuttle payloads)

For folks out in Arizona or New Mexico, Nevada and such... sure very inexpensive land is easy enough to find and in many cases NOT that far from major population centers and you can 'go to town filling vast areas with cheaper cells.. but in many other areas you're not gonna be so lucky.
lengould100
not rated yet Apr 28, 2010
I thought plants only converted solar energy at the rate of 1 or 2%..

That is correct, regardless of the erroneous following posts. Dye photosynthesis as practiced in nature is at best (perennial or bi-annual sugar cane in tropical environment with plentiful water and nutrients) 2% to 3% efficient at converting solar energy into stored carpohydrate energy. A temperate annual crop such as corn might be only 2% max. Reduce that for only 8 months growing season. Reduce that for imperfect irrigation and nutrient supply, weather damage, insect injuries, weed competition, etc. etc. 1% efficiency is likely optimistic for temperate climate photosynthesis as a solar collector system.