Designing New Materials to Kill Germs

Dr. Jaehong Kim, associate professor in the School of Civil and Environmental Engineering, and Ezra Cates, doctoral student in environmental engineering, were recently recognized by Chemical & Engineering News (C&EN) for their research in the development of nanomaterials which turn visible light into ultraviolet radiation that can kill germs.

Photo by Ezra CatesThe research team designed the nanomaterials so that when bright indoor lighting or in direct sunlight strikes them, they emit ultraviolet radiation that can damage pathogens' DNA. The coating of a fluorescent light bulb has the exact opposite effect as it turns ultraviolet radiation into visible light.

These new nanomaterials perform their transformation through a phenomenon called upconversion photoluminescence, first reported during the mid 1960s but never used to design materials for practical purpose. The process starts when a photon of blue light enters the material and excites an electron from a lanthanide atom. Next, if that excited state lives long enough, a second blue photon arrives and promotes the electron further. When the electron relaxes back to the ground state, it releases a single high energy photon of UV light.

Dr. Kim and Cates hope that someday in the future coating surfaces with these substances may help disinfect drinking water, sterilize hospitals, protect packaged foods, and keep bathrooms clean.

To read more about this leading research, please visit C&EN.