Materials development for mid-infrared plasmonic applications

With this award, the Chemical Measurement and Imaging program of the Division of Chemistry is funding Professors Stefan Franzen and Jon-Paul Maria of the North Carolina State University to explore how plasmon oscillations in the mid-infrared (IR) spectrum can interact with molecular vibrations to enhance the infrared characterization science. To accomplish this goal, the team implements extreme-mobility conductive metal oxides into thin film platforms that support surface plasmon resonance phenomena, and determines how to functionalize them for specific chemical attachments. Broader impacts of this work include scientific impacts well beyond this project, such as (i)the development of new methods to enhance sensing by mode mixing an IR plasmon and an IR absorption band, and (ii) merging IR surface plasmon resonance spectroscopy with fluorescence to monitor surface reactions at the monolayer scale. Educational broader impacts are to be achieved by providing a training ground for graduate students in an interdisciplinary, collaborative research environment.

This project merges complementary capabilities in Chemistry and Materials Science that may enable new chemical sensing capabilities. For example, the members of this collaborative research team seek to attach photoactive oligonucleotides to CdO:Dy films using new SAM chemistries and monitor binding simultaneously using fluorescence and mid-IR plasmonic detection. Heretofore, such strategies have generally not been seen using conventional plasmonic materials such as gold nanoparticles that quench fluorescence events. The team is also exploring new plasmonic oxides other than CdO with promising mobility and surface chemistry properties. The experiments include thin film preparation by molecular beam epitaxy and sputtering, film characterization by diffraction, infrared-ellipsometry, and electronic transport. Surface functionalization of these layers utilizes approaches based on chemical attachment with and without ultra-thin interface layers prepared by atomic layer deposition.