By Emily Little
Finding solutions to climate science takes multi-faceted collaboration from physicists, chemists, earth scientists and engineers in several different fields.
The Institute for Sustainability and Energy, or ISEN, at Northwestern is tackling this immense task through such collaborations. The institute launched in 2013 as a way to provide space for different research groups to come together with academic and corporate partners to accelerate advances in technologies, such as more efficient photovoltaics developed with innovative materials.
“I was really hoping to leverage this ability to bring everyone together into a central lab or a central location … like a collaborative workspace,” said Ryan Young, director of research at ISEN. “That type of lab space isn’t really that common.”
Collaboration between research groups is at the heart of this state-of-the-art facility. The institute built an 8,000-square-foot laboratory that allows scientists from different areas to work together solving the massive global climate challenges through what the researchers call “team science.”
“I think it speaks to Northwestern’s collaborative nature in general,” said Michael R. Wasielewski, Executive Director at ISEN. “I think many of the units and many of the departments of Northwestern tended a long tradition of a collaborative research.” Wasielewski is also the Claire Hamilton Hall Professor of Chemistry at Northwestern.
ISEN began as a sustainability initiative for education, research and outreach in 2008. The institute now offers a master of science in energy and sustainability as well as an undergraduate certificate, and several interdisciplinary classes to allow students to learn about the many aspects of sustainability research and application in the workspace.
ISEN offers a wide variety of areas of research at its facilities, such as the Flex Lab and GIANTFab Core facility. Research includes solar electricity and fuels, catalysis and green chemistry, sustainable materials and climate science.
Solar technology for the energy crisis
According to the U.S. Department of Energy, solar power has grown 35-fold in the United States, and the cost of solar panels has dropped nearly 50% over the past six years.
Solar cells come in all different forms, from the large silicon sheets typically found on buildings to wearable, more flexible devices. But the science between them is relatively similar.
Photovoltaics use materials called semiconductors. These are materials that are not quite conductors and not quite insulators, but rather fall in the middle. They have few “free” electrons to give up and have closely grouped atoms in crystal lattice structures.
When sunlight hits a solar cell, the electrons on the surface are excited via the photovoltaic effect. They can move through the bulk of the material and are not bound by one individual atom. Excited electrons and their remaining holes, called an exciton, have enough energy to move away from the excitation spot. This creates a current that can be used for everyday purposes.
Not all solar cells are created the same way, and different types of cells can work better in different situations. Thin film cells work better for wearable tech devices, while large glass panels work better in larger areas.
Solar energy has been studied since the 19th century, but it only became a viable option for the energy crisis during the 1970s. Since then, researchers and lawmakers have looked to making photovoltaic panels more available and more efficient.
Thin-film testing at the GIANTFab Core Facility
Nathan La Porte, operations director of the GIANTFab Core facility, believes that solar is the best option for alternative energy.
“That’s the only source of energy that is abundant enough to solve the energy problem,” La Porte said.
The GIANTFab Core facility, which stands for Glovebox Inert Atmosphere (N2) Thin-film Fabrication and Testing, allows for students and researchers to test their devices in a completely inert environment. Their work has focused on the manufacture and testing of organic, perovskite and hybrid solar cells.
A perovskite, or a material with the same crystal structure as calcium titanium oxide, can be used as a semiconductor to create a photovoltaic cell.
Justin Hoffman, a graduate student working with perovskite cells in the facility, believes that thin-film solar cells can be more cost effective.
“A thin film, which is a couple hundred nanometers thick, [can use] three grams of material for a very long time, because there’s so little material in the solar cell,” he said. “So a little bit that we make in synthesis is going to go a very long way.”
Not only are these thin-film solar cells more cost effective, but they have similar efficiencies to that of traditional silicon cells.
La Porte said that the most difficult aspect of solar cell fabrication is optimizing the process for particular materials.
“The other layers around the active layer are pretty standard,” La Porte said. “Getting the actual active layer to be the right thickness to have the right blend of the donor and the acceptor materials and tailoring that for the given materials that you have, I think, is the most challenging scientific [aspect].”
As the solar industry continues to grow in the United States, ISEN is hoping that they can use the GIANTFab facility to develop newer, more efficient means of solar electricity.
Solving the plastics crisis
In addition to solar technology, ISEN is looking into solutions for the current plastics crisis.
In a study by the American Chemistry Council, the United States was found to have generated 35.7 million tons of plastics in 2018. Moreover, 75% of those plastics were landfilled and less than 1% were recycled.
ISEN recognized that this was becoming a large problem and wanted to use its research teams to develop a strategy to combat this crisis. Among strategies, they are using catalysis to convert plastics into useful materials rather than waste streams polluting land and oceans.
Catalysis is a chemical process that lowers the activation energy of a reaction. By using catalysts to break down plastics, this becomes a relatively low-energy process to better recycle plastics.
“For instance, some of our colleagues have actually developed ways of taking plastic waste and essentially making it into motor oil,” Wasielewski said. “Consequently, you can take what normally ends up as a waste product and is harmful … and make it into something that is still useful to society.”
The institute holds a speaker series provided by the ISEN’s Program on Plastics, Ecosystems, and Public Health (PEPH). In a webinar on enzyme-catalysis in macromolecular synthesis, Professor Richard Gross of Rensselaer Polytechnic Institute discussed the use of bacterial cellulose and other new chemical catalysts. He believes that these new types of catalysis will use less energy than traditional methods.
“We haven’t calculated energy utilization but I believe that should be a low energy process,” Gross said. “The lipase catalysis, we’re keeping the temperature down around 90 to 110 degrees. That’s a lot lower than a lot of traditional chemical catalysts.”
By using less energy in chemical processes, ISEN researchers hope to save energy in these large-scale industries to reduce waste.
How do you become a part of ISEN?
ISEN’s Flex Lab and other facilities allow researchers from all different backgrounds to come together under one roof.
In order to be a user in the Flex Lab space, the researcher must show that their work fits within the realm of sustainability and energy. This research must also fit nicely with other work being done in the lab to ensure no interference. For example, the directors must ensure that one lab is not giving off exhaust that could hurt another group’s research.
GIANTFab is a university core facility and is open to any user who wants to use the equipment.
ISEN can only provide limited funding to its users, so they must come with their own way of raising money for specific projects. Academic customers are not charged rent, unlike corporate users.
This lab is truly hoping to be a meeting space for researchers. The developers want to make sure that everyone has access to their instruments and materials to produce the best research possible on sustainability and energy.
Within the coming months and years, Wasielewski hopes that ISEN will continue to pave the way for sustainability research and help solve the current global problems.
“We damaged the planet to the point where we can’t repair it anymore,” he said. “The number of years is diminishing, and so we need to act now.”
Emily Little is a health, environment and science reporter at Medill. You can follow her on Twitter at @EmilyM_Little.