NDSU’s Kilin receives NSF Creativity Extension Award to further photovoltaics research

North Dakota State University associate professor of chemistry and biochemistry Dmitri Kilin has received a Creativity Extension award from the U.S. National Science Foundation (NSF), which is an amendment to his NSF CAREER Award he received in 2020. The award is for Kilin’s project titled “Investigation of Laser-driven Chemical Reactions by Molecular Dynamics,” which focuses on offering an environment for others to create new computational tools that will give researchers the ability to work towards higher efficiency solar cells.

According to the NSF website, Creativity Extension awards “aim to offer the most creative investigators an extended opportunity to attack adventurous, ‘high-risk’ opportunities in the same general research area, but not necessarily covered by the original/current award. Grants eligible for such an extension are generally continuing grants. Special Creativity Extensions are normally initiated by the NSF Program Officer based on progress during the first two years of the grant.”

“We are incredibly proud of Dr. Kilin and his team's work. They've not only made significant progress on a foundational challenge—understanding and predicting complex photoreactions—but they've also demonstrated the vision to pursue entirely new, high-risk / high-gain directions,” said Heidi Grunwald, NDSU Interim Vice President for Research and Creative Activity. “Their focus on new methodologies, leveraging machine learning, could be a game-changer. This isn't just about advancing computational methods; it is also about the spirit of the NSF CAREER award, which merges research and education, aiming to inspire students to think creatively about modern-day scientific challenges and to pursue academic and industry scientific careers. The potential to selectively enhance desired products has profound implications for a multitude of applications. This is exactly the kind of transformative, translational, high-impact research we're committed to.”

Kilin’s research supports renewable energy growth, environmental sustainability, and innovation in energy-related technologies with broad societal and economic impacts. His work can potentially improve the efficiency of solar cells, enabling better use of solar energy for electricity generation, which can lower energy costs, reduce reliance on fossil fuels, and decrease harmful emissions, thus contributing to cleaner air and a healthier environment. The research also advances computational tools and understanding of photo-induced processes, which can aid in developing sustainable technologies like polymer upcycling to reduce plastic waste.

The research will remain on the same path as what was done with the original NSF CAREER Award, Kilin said, as the Creativity Extension Award will allow his group to keep growing what they’re doing, while continuing with the diversity of methods being developed and applied.

Kilin explains that when materials absorb light, their molecules may rearrange and form new substances or set electrons in motion, creating a flow of tiny charges inside a material. Understanding such a charge transfer process allows us to control the photovoltaic effect. It serves as an example of basic computational research that has the potential to have an impact on the industry of photovoltaic cells. The NSF noted this impact. ”The agency preferred the development of computational methodology to describe broader classes of processes,” he said.

The original NSF grant for the project allowed a method called TDESMD, or time-dependent excited state molecular dynamics, which is a method that is fast and useful for simulations, but does oversimplify how molecules interact with light. Kilin explained the concept: “The TDESMD method is based on a very rough approximation as the molecules are jumping between ground and excited electronics instantaneously, leaving the intermediate state when it is half excited, while in real life, it is a continuous process when the electromagnetic field of the laser and molecules are in a dynamic interaction. The TDESMD algorithm and computer code developed are competitively efficient but have potential for further development to increase precision and accuracy.”

One example of TDESMD in use is to computationally interpret and guide an experimental effort in upcycling polymers, or transforming used or waste plastics into new materials of equal or higher value than the original. “To clean the planet from plastic wastes, one can design plastic polymers so that they would degrade under UV lights,” Kilin said.

Kilin noted that the research has been a combined effort among many individuals, including several faculty collaborators and numerous NDSU students. Current NDSU Chemistry and Biochemistry graduate students David Graupner, Patricia Adeoye, and Adam Flesche, MNT graduate student Landon Johnson, Physics graduate students Hadassah Griffin and Eric Roeschlein; former undergraduate students Joseph Granlie and William Tupa; Aaron Forde, a former graduate student who graduated from Kilin’s group; and Kamrun Naha Keya and Amara Arshad, recent NDSU doctoral graduates.

“I’m grateful for all these young talents who do a great deal of the work, which allows me to throw in ideas and contribute options for our mutual research progress,” Kilin said.

Yulun Han, now an assistant professor of chemistry at Texas A&M-San Antonio, was a post-doctoral researcher at NDSU on the project through 2024. His research at NDSU focused on photoinduced processes such as light absorption, photoreactions, energy transfer, electron transfer and relaxation pathways.

“In addition to research, I learned firsthand from Dr. Kilin about how to teach effectively, incorporate research into teaching, recruit and mentor students, and build research progress step by step,” Han said. “The training I received from Dr. Kilin laid a strong foundation for my career.”

The contribution of graduate students, undergraduate students and other researchers has played a role in the development.

“I worked on creating code that would do some additional calculations on the original data to incorporate exciton effects into the Redfield tensor,” NDSU graduate student Hadassah Griffin said. “That's allowed us to see a small correction in predictions of what a photoluminescence quantum yield would be for some quantum dots, as well as relaxation rates for different nanoparticles.”

“I'm trying to develop a method that will actually simulate the excitation process itself,” NDSU graduate student Landon Johnson said. “Hopefully, in a scalable manner, we can simulate large molecules and nanostructures and do it at large timescales,” Kilin added. Landon’s work aims to treat electromagnetic-made molecular vibrations and electronic excitation on equal footing.

The Creativity Extension Award will provide opportunities to develop even more new methods and focus on new processes, said Kilin.

Kilin suggests combining 2D materials and polaritons can lead to new effects like chiral photoluminescence (light emission with a handedness or twist) in carbon quantum dots. These carbon quantum dots are tiny semiconducting particles that can be made inexpensively (even by microwaving in a kitchen), making them accessible for applications in computing or photonics.

“The effects which modify the optoelectronic properties between closely spaced mirrors are expected to be promising directions,” Kilin said. “It could be chiral photoluminescence in carbon quantum dots, which can be in addition to computations. They can be easily fabricated without expensive equipment, and one can do it in the kitchen using a microwave.”

Kilin’s work is supported by an NSF CAREER Award 1944921 and is enhanced by partnering with Los Alamos National Lab.