(556f) High Dielectric Semiconductor Nanostructures with Tunable Mie Resonance in the Visible to Near-IR Region

Over the years plasmonic materials have received wide attention for their ability to trap the light^1–3. Plasmonic nanoparticles (NPs) exhibit strong electromagnetic-field enhancement for the incident light because of the Localized Surface Plasmon Resonance (LSPR). This property has been shown to enhance the photocatalytic performance of nearby semiconductors in the composite, and hybrid photocatalysts build on plasmonic metal nanoparticle and semiconductor. In this contribution, we will show a new family of materials called optically resonant high dielectric nanostructures⁴ which exhibit strong Mie scattering and absorption in the visible to near-IR region.

Our FDTD simulation results predict that the electromagnetic-field enhancement observed over high dielectric NPs are 2-3 orders of magnitude higher than the plasmonic NPs. This new family of non-plasmonic metal oxide (semiconductor) nanostructures is dielectric in nature with high refractive index (> 2). Our simulation results predict that the Mie resonance over these high-dielectric nanostructures can be tuned anywhere from UV-Vis to the near-IR region by controlling the geometry of the nanostructures. We will also show experimental results that validate the simulation results. We utilized size and shape-controlled synthesis techniques to design optically resonant nanostructures with tunable Mie resonance. The optoelectronic properties of these nanostructures are confirmed using a number of spectroscopic techniques. 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 thin-film solar cell applications.

References

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2. Christopher, P., Xin, H., Marimuthu, A. & Linic, S. Singular characteristics and unique chemical bond activation mechanisms of photocatalytic reactions on plasmonic nanostructures. Nature Materials 11, 1044–1050 (2012).
3. Linic, S., Christopher, P., Xin, H. & Marimuthu, A. Catalytic and Photocatalytic Transformations on Metal Nanoparticles with Targeted Geometric and Plasmonic Properties. Accounts of Chemical Research 46, 1890–1899 (2013).
4. Kuznetsov, A. I., Miroshnichenko, A. E., Brongersma, M. L., Kivshar, Y. S. & Luk’yanchuk, B. Optically resonant dielectric nanostructures. Science 354, aag2472 (2016).