Special Light-Absorbing Layer Makes Polymer Solar Cells 20% More Efficient

ioawa state polymer solar cells photo

Sumit Chaudhary, left, and Kanwar Singh Nalwa of Iowa State University and the U.S. Department of Energy's Ames Laboratory. Photo: Leah Hansen/ISU
Polymer Solar on the Road to Commercial Viability
When it comes to solar panels, one-size-doesn't-fit-all. Sometimes what you need it maximum efficiency (such as on a satellite) at whatever cost, but sometimes low-cost and flexibility are paramount. Polymer solar cells aren't yet commercially viable, but they show a lot of promise when it comes to those latter characteristics, and thanks to breakthroughs from labs all around the world, they could one day become ubiquitous. One such advance comes from the Iowa State University and the Ames Laboratory. Read on for details.
[Sumit Chaudhary, an Iowa State assistant professor of electrical and computer engineering and an associate of the U.S. Department of Energy's Ames Laboratory,] said the key to improving the performance of solar cells made from flexible, lightweight and easy-to-manufacture polymers was to find a textured substrate pattern that allowed deposition of a light-absorbing layer that's uniformly thin - even as it goes up and down flat-topped ridges that are less than a millionth of a meter high. 'Our technology efficiently utilizes the light trapping scheme, and so solar cell efficiency improved by 20 percent.'

Tests also showed that light in the red/near infrared band edge was captured at a rate 100 percent higher than with flat cells.

Trapping More Light
So this special layer makes the polymer cell capture more energy not by directly converting a higher percentage of light into electricity, but by capturing more light to begin with so that even if the ratio of converted light isn't higher, the total amount of energy produced is still higher. This is a great way to do things because if you can then improve the conversion efficiency of the cell, you get a compounding effect.

It works a bit like: New Solar Cell is 98% Plastic and Catches a Record-Breaking 96% of Incident Light, which uses another way to capture more light (nanowires, instead of this textured layer).

Via Iowa State University
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