(661r) Photocatalysis on Optically Resonant High Dielectric Nanostructures

In recent years, plasmonic metal nanostructures (PMNs) have received wide attention for the conversion of solar energy into chemical energy. PMNs exhibit strong electromagnetic-field enhancement for the incident light because of the localized surface plasmon resonance. This property has been shown to enhance the photocatalytic performance of nearby semiconductors in the hybrid nanostructures built on PMNs and semiconductors. In this talk, we will show a new family of materials called optically resonant dielectric nanostructures which exhibit strong Mie resonance in the UV-Vis-near-IR region.

Our results show that the electromagnetic field enhancements observed over high dielectric nanostructures are up to an order of magnitude higher than the PMNs. This new family of non-plasmonic metal oxide semiconducting nanostructures is dielectric in nature with high refractive index (> 2). Our results also show that the Mie resonance on these high-dielectric nanostructures can be tuned anywhere from UV-Vis to the near-IR region by controlling the geometry of the nanostructures. We utilized size- and shape-controlled synthesis techniques to design optically resonant nanostructures with tunable Mie resonance. The Mie resonance-induced energy transfer (MIRET) pathways in these nanostructures are confirmed using a number of spectroscopic techniques and photo-reduction-oxidation (photoredox) studies. The design rules developed for the optically resonant nanostructures in our study will potentially have a wide range of applications including the use of these nanostructures for solar light-driven photocatalysis and dye-sensitized solar cell applications.

References

1. Andiappan, M., Wheeler, A., Tirumala, R. T., Ramakrishnan, S., Mohammadparast, F.; “Photocatalysis using Mie Resonances of Cu₂O Dielectric Nanostructures” US Provisional Patent, 12/09/2019, U.S. Serial No.: 62/932,991.
2. Mohammadparast, F.; Ramakrishnan, S. B.; Khatri, N.; Tirumala, R. T. A.; Tan, S.; Kalkan, A. K.; Andiappan, M. Cuprous Oxide Cubic Particles with Strong and Tunable Mie Resonances for Use as Nanoantennas. ACS Appl. Nano Mater. 2020, 3 (7), 6806–6815.