3-D Images Provide First Look into Polymer Solar Cells

Grab your popcorn. Unfold those cereal-box shades. Sit back and kick your feet up… because researchers in the Netherlands are taking the first high-res, 3-D glimpse into a polymer solar cell. Well, tickets for the show may not be readily available, but scientists at the Eindhoven University of Technology will gladly share their experiences.

Polymer solar cells are an important avenue for the nanotechnology wing of solar R&D. Having a 3-D image of these miniscule cells provides valuable insight into their structure at a nanoscale level and how that structure affects cell performance.

The Polymer Potential

Polymer solar cells are fascinating for solar researchers due to their potential for low-cost, flexible and lightweight solar modules. Currently, efficiencies for polymer cells are very low (2% at best), but production costs are also very low. These cells can be manufactured in a printing press-like application that is extremely fast and relatively simple compared with processes for silicon-based solar cells.

Researchers are hoping that a 3-D glimpse into polymer cells will open up new possibilities for improving efficiency to complement already low costs and extreme flexibility.

In the Mix

3-D imaging seems to show the most promise for hybrid polymer solar cells, which use a mixture of polymer and metal oxide to create electrical charges when exposed to sunlight. Efficiency for hybrid cells is intimately related to the level of mixing at the nanoscale.

Using 2-D visualization, scientists had found it hard to get the right mix. By taking a more intimate, third-dimensional look into cell structure, researchers at Eindhoven found the root of the problem and have already made substantial improvements. They’ve added a third compound that better regulates the mixing process, allowing for better solar absorption rates across a wider area and improved recovery of electrical charges. Or in other words, better cell efficiency.

Still a Long Way to Go

These hybrid polymer cells may be the most efficient among polymer solar cells, but this still only equals that 2% mentioned earlier. There’s still a long way to go before the cells are truly useful. Researchers will have to work further to improve control over the polymer mix, for which the advantage of 3-D imaging should help considerably.

Posted on September 28th in Solar Information by Dan.