Graduate student Grant Olson runs an experiment involving the hybrid solar cells. | Samantha Sullivan/Mustang News

Samantha Sullivan
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Cal Poly is giving solar cells a facelift.

Walk between Graphic Arts (building 26) and Engineering South (building 40) on Monday and Wednesday nights. You will come across a smaller building and hear some humming emitting from it. That humming is coming from a printing press — the same one that prints Mustang News.

Now imagine thin, flexible sheets of plastic running through the rollers instead of newspaper. Mix in some polymers with the ink. Print it onto the plastic. You’ve just printed solar cells.

A group of Cal Poly research students are working to improve solar cells. The cells are hybrid cells — they are composed of organic, electronic-based polymers. They are more effective at converting solar energy and more cost effective. Additionally, the group is working on roll-to-roll processing — printing solar cells on thin sheets of plastic, much like how newsprint is printed onto newspaper.

“With roll-to-roll processing you just stick on this giant roll of plastic, hit the button and it just goes,” graduate student Grant Olson said. “And it will make an immense amount of these things very rapidly.”

Olson said the polymers and coatings program is working with the graphic communication department to see if this option is viable.

“If it works, then that means the fabrication of these devices is even easier than we thought,” Olson said.

Printing polymers isn’t the only change. Olson and the team are working on hybrid solar cells as well. And they are doing so in a unique way.

“What’s special and exciting about the research that we’re doing is we’re showing that a type of device that has not really been proven to be effective works,” Olson said.

The research

Physics professor Robert Echols has been working with solar cells since 2001. He originally got into solar energy because he said it’s very important for people to transition away from non-renewable energy.

According to Echols, there are three advantages to the hybrid polymer-based solar cells: that the system is robust, works well and is cost effective.

“To be able to get solar energy out of the lower cost is very important,” he said.

The hybrid solar cells involve polythiophene, an organic, electronic polymer. While this polymer has existed for some time, Olson’s group combines it with an inorganic material called zinc oxide. This hybrid material increases the electron transfer and the efficiency of power production.

Currently, solar cells are made up of inorganic, rigid materials, such as silicon. To create a solar cell out of silicon requires a lot of energy and money, Olson said. Organic materials, on the other hand, are easier to manipulate.

“So all of the advancements that my group is doing is making sure that we can ensure good electrical contact between those two materials,” Olson said.

Additionally, silicon-based solar cells are thick and brittle. The organic devices are very thin and flexible. This means the material costs less because you don’t need as much of it.


According to Olson, what’s holding solar energy back is not the lack of space; people don’t decide how many solar panels to install based on the size of their roof, they determine it based on cost. Olson and his research team’s goal is to lower that cost per watt.

This unique research hasn’t gone unnoticed, either. Olson presented his project at the Western Coatings Symposium in Las Vegas this past fall, where he won second place.

Chemistry assistant professor Shanju Zhang is in charge of the graduate students working on this project. He’s also the one who came up with the idea for it.

“To make the polymer solar cells, it’s a big dream for scientists,” he said. “A lot of those people make effort trying to do this, trying to improve efficiency, trying to make a lot of cells at a low cost. But it’s a huge challenge, a huge challenge.”

The National Science Foundation granted Zhang funds for one-and-a-half years for the project, and he will be writing a grant proposal for another year soon. Because these are new materials and because the printing process is a new idea, Zhang said this is a long-term project.

“Even if I don’t have funding, I may still continue to do the project,” he said.

As for the project, the first thing is to make sure this concept works, Zhang said, then the focus can shift toward large-scale production.

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