Materials that emit and manipulate light are at the heart of technologies ranging from solar energy to advanced imaging systems. But even in well-studied materials, some fundamental behaviors remain unexplained. Researchers at Rice University have now solved a long-standing mystery in a widely used organic semiconductor, revealing how tiny structural imperfections can actually improve how these materials work.

In a study published in the Journal of the American Chemical Society, the team investigated 9,10-bis(phenylethynyl)anthracene (BPEA), a model system for studying how light energy moves through materials. For years, scientists have observed unusual optical behavior in BPEA, specifically two distinct absorption and emission signals that did not match existing theories.

“This was a long-standing puzzle in the field,” said Colette Sullivan, a doctoral student in Rice’s Department of Chemistry and co-author of the study. “Once we connected the experimental results with theory, it became clear the two signals were coming from completely different processes.”

Researchers have found a way to use solar energy to power a key chemical reaction that drives many manufacturing industries. This new method can significantly reduce the energy required to run these operations, eliminate harsh oxidizing byproducts and minimize carbon emissions.

Olefin epoxidation is not a process many are familiar with, but the epoxide chemicals it produces are the backbone of the textile, plastic, chemical and pharmaceutical industries. However, the current industry-standard process uses harsh peroxides to facilitate oxidation reactions, which are difficult to dispose of safely and emit carbon dioxide.

Water can be used as an oxidant instead of peroxides, but H₂O bonds are difficult to break, requiring high-temperature conditions, making it highly energy-intensive and further contributing to CO₂ emissions.