(321c) Dielectric Nanostructures for Solar Light Harvesting Applications

The plasmonic metal nanostructures (PMNs) such as silver and gold nanoparticles, have been extensively studied to manipulate and amplify electromagnetic fields at the nanoscale. This ability resulted from a special property called localized surface plasmon resonance (LSPR). Exploiting this property led to plethora of applications, including nanoscale optics, photovoltaics and photocatalysis. However, there are inherent problems associated with plasmonic metals, such as high heating losses, and poorer compatibility with scaling-up compared to metal-oxide-semiconductor (CMOS) microfabrication processes. These limitations prevent the broader use of PMNs in real applications. On exploring the size- and shape- controlling particle synthesis techniques, spectroscopic methods, and finite-difference-time-domain simulations, we show that the Mie resonance driven size- and shape-dependent materials that are tunable in the visible to near-infrared regions are an alternate to PMNs. The choice of material is cuprous oxide (Cu₂O), a p-type semiconductor with a bandgap of 2.1 eV, medium refractive indexed and dielectric in nature. The effect of Mie resonance tailored by varying shape and size, helping in improving light absorption and increased reaction rates. These metal-oxides are tunable through shape and size to find applications in harvesting wider fraction of solar energy in thin film solar cells, dye sensitized solar cells, surface-enhanced Raman spectroscopy, photocatalysis, and other photovoltaic devices. In this work we will show how these light harvesting properties can used in applications like photocatalysis and dye sensitization using probe reactions.

Reference

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. https://doi.org/10.1021/acsanm.0c01201.