Mechanical engineering PhD wins Rath Award at Fall 2023 Graduate Commencement

Steven DiGregorio, PhD in Mechanical Engineering, is the winner of the Fall 2023 Dr. Bhakta Rath and Sushama Rath Research Award.

The honor, which recognizes the Colorado School of Mines doctoral graduate whose thesis demonstrates the greatest potential for societal impact, was presented during Fall 2023 Graduate Commencement on Dec. 15. At the ceremony, Mines awarded a total of 72 doctorates and 270 master’s degrees to August and December graduates. 

DiGregorio’s dissertation, “Interfacial Reduction Phenomena in Self-Reducing Reactive Silver Ink Systems,” presents new techniques for producing high performance solar cells that dramatically reduced usage of silver by 90 percent.

These results are critically important because using current silver metallization techniques, an estimated 80 percent of the world’s silver production would be consumed by the projected growth of the solar energy industry. DiGregorio’s research focused on developing reactive silver inks with high density, improved electrical properties – which ultimately reduces the amount of silver required for solar cell manufacturing by a factor of 10.

“Reactive inks are a relatively new field, and Steven’s research resulted in an entirely new approach to electronic printing,” said Owen Hildreth, associate professor of mechanical engineering and DiGregorio’s PhD advisor. “Additionally, the energy yield from a photovoltaic panel can be increased between 4 and 22 percent using Steven’s invention. This is an incredible result given that most gains in commercial photovoltaics are measured in tenths of a percent. Overall, his research is a key contribution to producing the terawatt levels of solar electricity the world needs.”

DiGregorio’s work is already being used by commercial companies looking to leverage the benefits of reactive silver inks for reduced costs, increased sustainability, and improved performance. 

During his time at Mines, DiGregorio was first author on four peer-reviewed journal articles, co-author on five, and first author on an invited book chapter. He is also a co-inventor on two Provisional Patent applications submitted to the U.S. Patent and Trademark Office.  Following graduation, Steven has taken a position at Sandia National Laboratory, where he is continuing his work making solar energy efficient, reliable and affordable.

Finalists for the Rath Award were:

• Bikram Adhikari, Quantitative Bioscience Engineering, “Biomimetic Human Tissue Models and Their Application in Disease Pathology Studies and Therapeutic Interventions”
• Sarah V. Boardman, Materials Science, “Understanding the Influence of Process Parameters on the Mechanical Properties of Alumina Formed Through Lithography-Based Additive Manufacturing”
• Kejun Chen, Chemical and Biological Engineering, “Unlocking Pathways to High Performance Silicon Photovoltaics: Novel Passivating Contacts, Improved Device Architectures, and Advanced Characterization”
• James C. Grymes, Operations Research with Engineering, “Optimal Design and Dispatch of Hybrid Co-Generation Microgrid Systems with Resilience Considerations”
• Ruchen Wen, Computer Science, “Context-Sensitive Representations, Reasoning, and Communication for Morally and Socially Competent Robots”

Other Graduate Student Awards

Chemical and Biological Engineering

• Outstanding Thesis Award: Kejun Chen

Humanitarian Engineering and Science

• Outstanding Graduate Student Award: Marisa Macias

Mechanical Engineering

• Emeritus Faculty Exemplary Graduate Student Award: Joe Eriqat
• Outstanding Dissertation Award:Steven DiGregorio