Major advance in organic solar cells

October 19, 2009

Professor Guillermo Bazan and a team of postgraduate researchers at UC Santa Barbara's Center for Polymers and Organic Solids (CPOS) today announced a major advance in the synthesis of organic polymers for plastic solar cells.

Bazan's team:

  • reduced reaction time by 99%, from 48 hours to 30 minutes, and
  • increased average molecular weight of the polymers by a factor of more than 3.
The reduced reaction time effectively cuts production time for the organic polymers by nearly 50%, since and purification time are approximately equal in the production process, in both laboratory and commercial environments.

The higher molecular weight of the polymers, reflecting the creation of longer chains of the polymers, has a major benefit in increasing current density in by as much as a factor of more than four. Over batches with varying average molecular weights, produced using varying combinations of the elements of the new methodology, the increase in current density was found to be approximately proportional to the increase in average molecular weight.

The methodology, detailed in a Nature Chemistry paper published online today and slated for later inclusion in the print publication, "will greatly accelerate research in this area," stated Bazan, "by making possible the rapid production of different batches of polymers for evaluation." He further noted, "We plan to take advantage of this approach both to generate new materials that will increase solar cell efficiencies and operational lifetimes, and to reevaluate previously-considered polymer structures that should exhibit much higher performance than they showed initially."

To make these gains, the team:

  1. Replaced conventional thermal heating with microwave heating,
  2. modified reactant concentrations, and
  3. varied the ratio of reactants by only 5% from the nominal 1:1 stoichiometric ratio normally employed in polymerization reactions.

Mike McGehee, Director of Stanford's Center for Advanced Molecular Photovoltaics, hailed Bazan's work, commenting, "Many synthetic chemists around the world are making copolymers with alternating donor and acceptors to attain low bandgaps. Most of them are having trouble attaining adequate molecular weight, so this new synthetic method that creates longer polymer chains is a real breakthrough. The reduction in synthesis time should also make it easier to optimize the chemical structure as the research moves forward and will ultimately reduce the manufacturing cost."

More information: Nature Chemistry paper: dx.doi.org/10.1038/NCHEM.403

Source: University of California - Santa Barbara (news : web)

Explore further: Chemists reinvent the science and industry of making plastics

Related Stories

Chemists reinvent the science and industry of making plastics

October 12, 2006

Chemists at the University of Pennsylvania have created a new process for free radical polymerization, the chemical reaction responsible for creating an enormous array of everyday plastic products, from Styrofoam cups to ...

Clicking synthetic and biological molecules together

February 19, 2008

Dutch researcher Joost Opsteen has developed a method to click polymers together in a controlled manner. Using this method, he can even attach proteins to nanoballs. For instance, this approach could be used to transport ...

Discovery brings organic solar cells a step closer

January 15, 2009

Inexpensive solar cells, vastly improved medical imaging techniques and lighter and more flexible television screens are among the potential applications envisioned for organic electronics.

Recommended for you

New chemistry makes strong bonds weak

July 28, 2015

Researchers at Princeton have developed a new chemical reaction that breaks the strongest bond in a molecule instead of the weakest, completely reversing the norm for reactions in which bonds are evenly split to form reactive ...

Making polymers from a greenhouse gas

July 28, 2015

A future where power plants feed their carbon dioxide directly into an adjacent production facility instead of spewing it up a chimney and into the atmosphere is definitely possible, because CO2 isn't just an undesirable ...

New material opens possibilities for super-long-acting pills

July 28, 2015

Medical devices designed to reside in the stomach have a variety of applications, including prolonged drug delivery, electronic monitoring, and weight-loss intervention. However, these devices, often created with nondegradable ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.