Nanomaterials and Light for Sustainability and Societal Impact
Naomi J. Halas
Metallic nanoparticles, used since antiquity to impart intense, vibrant color into materials, then brought to scientific attention in the 19th century as “Faraday’s colloid”, have more recently become a central tool in the nanoscale manipulation of light. When excited by light, metallic nanoparticles undergo a coherent oscillation of their conduction electrons- known as a plasmon- which is responsible for their strong light-matter interactions and properties. While the scientific foundation of this field has been built on noble and coinage metals (most typically gold or silver), more recently we have begun to question whether the same, or similar properties can also be realized in more sustainable materials. Aluminum, the most abundant metal on our planet, can support high-quality plasmonic properties spanning the UV-to-IR region of the spectrum. Coupling a plasmonic nanoantenna directly to catalytic nanoparticles transforms the entire complex into an efficient light-controlled catalyst capable of driving chemical reactions under surprisingly mild, low temperature conditions. This new type of light-based catalyst can be utilized for remediating greenhouse gases, and converting them to useful molecules for industry, or benign molecules for a cleaner planet. We have previously introduced photothermal effects for biomedical therapeutics; now, years after their initial demonstration, this approach is being utilized in human trials for the precise and highly localized ablation of cancerous regions of the prostate, eliminating the highly deleterious side effects characteristic of conventional prostate cancer therapies. Photothermal effects can also be harvested for sustainability applications, which we have most recently demonstrated in an off-grid solar thermal desalination system that transforms membrane distillation into a scalable water purification process.
Naomi J. Halas is the Stanley C. Moore Professor of Electrical and Computer Engineering at Rice University, where she also holds faculty appointments in the Departments of Physics and Astronomy, Chemistry, Materials Science and Nanoengineering, and Bioengineering. She is best known as the first person to demonstrate that controlling the geometry of metallic nanoparticles determines their color. She pursues studies of plasmonic and nanophotonic systems and their applications across a range of fields. She is author of more than 300 refereed publications, has more than 20 issued patents, and has presented more than 600 invited talks. She has been awarded the Frank Isakson Prize and Julius Lilienfeld Prize of the APS, the Willis E. Lamb Award, the R. W. Wood Prize of the OSA, the ACS Award in Colloid Chemistry, and the Spiers Memorial Award of the Royal Society of Chemistry. Halas has been elected to the National Academies of Sciences and Engineering (USA), the Royal Society of Chemistry (UK) and the American Academy of Arts and Sciences.