Powering the Future: U.S. Students Gain International Experience Through Photovoltaics Research in Berlin

Daniel Morton — Tue, 26 Aug 2025 19:43:01 +0000

Powering the Future: U.S. Students Gain International Experience Through Photovoltaics Research in Berlin Daniel Morton Tue, 08/26/2025 - 13:43

Lauren Scholz

A summer of international research concludes as U.S. students contribute to solar innovation in Berlin while gaining hands-on training and global scientific perspective through the NSF-IRES Program.

We are proud to celebrate the successful completion of our first cohort of students bound for Berlin as part of the National Science Foundation International Research Experience for Students (NSF-IRES) Program in metal-halide perovskite photovoltaics. Over the course of ten intensive weeks, nine students from universities across the United States immersed themselves in collaborative research at Humboldt-Universität zu Berlin and Helmholtz-Zentrum Berlin. Their work focused on advancing next-generation solar technologies—specifically, the development and optimization of metal-halide perovskite solar cells.

This timely exchange supported critical progress in the field of photovoltaics, where metal-halide perovskites offer promising pathways to higher efficiency and more versatile solar solutions beyond the limits of conventional silicon-based technologies. By engaging directly with leading German research teams, students not only deepened their technical knowledge and experimental skills but also gained valuable cross-cultural experience and a global perspective on scientific collaboration.

Selected for their academic excellence and commitment to renewable energy innovation, the participants—ranging from undergraduate to graduate level—contributed to a variety of interdisciplinary projects in chemistry, physics, materials science, and engineering. Their contributions helped strengthen the scientific partnerships between U.S. and German institutions and demonstrated the impact of international collaboration in addressing global climate and energy challenges.

Find out more about the 2025 IRES Cohort

2025 NSF IRES-Perovskites participants. Pictured (left to right): Megan Davis, Keya Amundsen, Jiselle Ye, Jack Schall, Keenan Wyatt, Kell Fremouw, Leo Beck, Gabriel Graf. Not pictured: Arial Brookhart.

August 2025

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Profile: Collin Sindt

Daniel Morton — Mon, 07 Jul 2025 18:59:39 +0000

Profile: Collin Sindt Daniel Morton Mon, 07/07/2025 - 12:59

Daniel Morton

Collin Sindt, a graduate student in Chemical and Biological Engineering, co-advised by RASEI Fellows Seth Marder and Mike Toney, explores the molecular structure of advanced materials for harvesting solar energy. As part of his collaborative work Collin recently spent a few weeks doing research over in Berlin, Germany. We caught up with Collin to learn a little more about his work, what led him to this research, and find out more about his time in Germany.

Where are you from?

I grew up in Dubuque, Iowa. It is at the point where Iowa, Wisconsin, and Illinois all meet. It is a pretty rural area with a lot of farmland, with pretty views along the river. The backcountry in Iowa is mainly cornfields, but Dubuque has many bluffs and forests near the Mississippi river.

What did you get up to as a kid?

I was pretty heavily involved in the Scouts, joining early on when I was in kindergarten. It started out as a great way to hang out with your friends, but it really built from there into something I really cared about and wanted to be more involved in. Something that really spoke to me was the elements of environmental stewardship and conservation that are woven in, things like leave no trace and leave a space better than you found it. These were perspectives that have really guided my thinking ever since.

What did you want to be when you grew up?

It was pretty nebulous early on, though I wanted to do something in science or engineering since that was what I was best at in school. Simultaneously, scouting was something that really gave me a love for the outdoors, and I wanted to do something to help the climate crisis as I learned more about it. In Iowa we don’t have a lot of natural areas, like Colorado, but that means that we really cherish the ones we do have. Growing up I learned a lot about environmental stewardship and conservation of these spaces from a young age. When I got to college, I didn’t know exactly what I wanted to go into, but I knew I wanted it to incorporate these elements of protection of the environment. My preference for STEM subjects, chemistry in particular, eventually led me into chemical engineering as a major. As I found out more about the subject, I was really drawn to how chemical engineering interacts with the energy industry and, by extension, the climate. Historically that took the form of petrochemicals, but nowadays chemical engineering is much more a part of the expanding variety of renewable technologies, such as batteries and solar panels.

How would you describe your current research in five words?

Better understanding high-performing solar materials.

What led you into this area of research?

In my freshman year of undergrad I was deciding whether to pursue pre-medicine or go more into renewable energy and sustainability. I reached out to a few professors at Iowa who were engaged in renewable energy research and eventually wound up with a position working on photoelectric catalysis. That was the coolest thing I’d ever worked on, and I was hooked from there. I built and tested modular reactors, using catalysts affixed to solar cells to produce hydrogen from water. That got my foot in the door, and I have been interested in renewable energy research ever since. As I explored pursuing a PhD, I wasn’t set on continuing catalysis research, so I was interested in schools which offered a wide variety of renewable energy focused projects. This eventually led me to my current renewable energy research at �鶹��Ѱ��Boulder. I eventually made a connection and started working with Seth Marder and Mike Toney who had an open position working between them on characterizing solar energy materials.

The class of materials which are the subject of my research are called self-assembled monolayers, essentially a single layer of molecules, so we are working on very, very small length scales. These have become a staple in the field of solar energy research as they boost performance and are a very easy material to work with. In a solar cell you have the layer that absorbs light and then sandwiching that you have two layers that push the current in one direction. These are called charge extraction layers and that is where these monolayers are used, and where my work is focused. These self-assembled monolayers are fairly new as an approach to charge extraction layers in solar cells. There are other materials that can be used as charge extraction layers, such as polymers or metal oxides, but as with any electrical phenomenon, the larger the layer, the larger the voltage loss across it as you try and transport charge. So, if you can make it really thin, such as one molecule thick, you can significantly reduce the energy lost in transport. When operating at such small length scales, it is hard to figure out what it is about these materials that makes them good at what they do. My work employs a variety of techniques to try to answer this question. Essentially, I use a lot of different versions of shining light, mainly in the form of x-rays, on a sample and investigating the signal that comes off. By looking at this we can tell whether our molecules are chemically bonded to the surface, how many molecules are on the surface, and even what orientation they are in. By experimenting with different chemistries and materials we can start to build up a more complete picture of what about them impacts solar cell performance.

You work across two research groups and have experience with a number of collaborations, say a bit more about these aspects of your work.

From a materials perspective I work as part of the Marder group, which has a wealth of expertise in the organic chemistry of semiconducting charge transfer materials. When I came in as a new graduate student, I had the option to pursue a more synthetic chemistry route with them, developing new compounds to use in solar cells. However, there was already a library of different compounds to explore within this family when I arrived. So, instead, I have been developing my expertise in characterizing and understanding this library of materials, leveraging the expertise in the Marder group on how to handle, process and optimize them. Coupling that with the expertise in the Toney group, which contains vast experience in the applied characterization to understand the structure of such materials, it has been a very interesting and fruitful collaboration.

With X-rays, you are working on energy scales that correspond to the electronic excitations within atoms – so you can probe things like the oxidation state of a given element and the energy needed to remove an electron from that system. It also gives you the ability to measure distances between atoms and how atoms and molecules are oriented in space. There is a large number of X-ray methods out there and many of them benefit greatly from having an X-ray source that you can reliably tune the energy and the intensity of. But, to get these high-quality X-rays you often need to go to a synchrotron, where I’ve had the privilege to do a large amount of my own research. These are large government facilities which have a particle accelerator at their core, with electrons in a huge ring moving very close to the speed of light. We can then use magnets to bend their trajectory, which causes the emission of light, and if they are moving fast enough, you get X-rays, which can be shone onto our samples for these experiments.

The opportunity to work with these synchrotrons has been amazing for me. Not only does it let me do experiments that would otherwise be impossible, but it has been a great opportunity to develop and learn. To get time at the facility you have to apply, and it has taught me to be a better scientific writer and given me practice at communicating my ideas effectively. It has also been humbling to work with these kinds of instruments. These are huge, billion-dollar facilities, and the chance to run experiments there is amazing.

If you had told me when I was an undergrad washing up my glassware after running reactions that I would one day be working on such a machine I wouldn’t have believed you!

It has also led to some international collaboration. Building on an existing collaboration between the Marder Group and Norbert Koch at Humboldt University in Germany, we were looking at very similar materials. Seth from a chemistry perspective and Norbert from a physics perspective. While the synchrotron work I have done is very good for looking at the orientation of molecule, it can be hard to determine whether you have a single layer, two layers, or multiple layers. This is something that the Koch group are experts at, and as part of building this international collaboration that is ongoing, I was able to go across to Germany with my materials for three months in the fall of 2024. This helped accelerate my research and I really learned a lot about a technique called XPS and other photoelectron spectroscopies done in Germany.

Berlin was a fantastic experience. I wish I had explored more of Germany, but the parts I did see where amazing. Berlin is a big city, and there is always lots to do. I was pleasantly surprised by how many parks there were in the city and how easy they were to get to. I was on the south-eastern side of the city, and there were parks that you could easily walk to. It is a really beautiful city.

What excites you about the future of solar technologies?

I am really looking forward to the manufacturing of these solar materials taking off. For solar and batteries technologies the challenges are technical and industrial as opposed to locational. Wind farms require specific locations, while solar and batteries can go almost anywhere. I am hopeful that the deployment of these types of systems will scale with their production capacity as opposed to systems like wind turbines where there is a lot more embedded in the locational permitting and transmission infrastructure. When we reach high-throughput production we will see distribution across a wide range of applications, which will open up all sorts of opportunities.

What do you like to do outside of work?

Being part of the Scouts really gave me a love of the outdoors. Growing up in Iowa there is not the same kind of parks as you find in places like Colorado, but I was able to take part in projects for stewardship and conservation. In 2016 I had the opportunity to get more involved and in the summers I spent time at the Philmont Scout Ranch in New Mexico. This is the largest adventure base in the world, something like 250 square miles in the Sangre de Cristo mountain range in New Mexico. I went out as part of a program where I spent a week building trail, constructing new conservation projects on the property and then the other week you were on a trek. In some summers there would be as many as 50,000 scouts that would come through the camp, so to have any hope of it being sustainable we would be taught about the impact we were having on the land and think about ways we could mitigate that.

I enjoyed my time there so much that in a following year I went back as a staff member to lead some of the work. The first year that I went out as a staff member there was a very large wildfire before the summer got started. Since we were already trained in land conservation, the team I was part of ended up sticking around and helping do mitigation work that summer. That experience was extremely impactful for me. I went back in 2021 and led some groups and could talk about and show them the impacts of the fire. It was very tangible.

So, all of this experience has really given me a love for being outdoors and I love exploring Colorado. I enjoy skiing, mountain biking, I have recently got into road cycling, and I love hiking. Another big hobby of mine is motorcycling, which is great to pair with getting out into the mountains. I have an adventure bike and that opens up a wide range of options and spaces. I also have a love of board games, for the times when the rain is too much for being out on a bike.

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