UC Riverside

Plasmonic nanostructures have attracted significant attention due to their tunable optical properties and broad applications in chemical sensing, photothermal therapy, and energy conversions. The plasmonic properties of the nanoparticles are sensitive to the size, morphology, and composition of the metal nanoparticles. Although the wet chemistry synthesis of plasmonic nanoparticles with well-controlled geometries has been widely studied, the systematic tuning of novel plasmonic nanostructures can broaden the application scenarios. It brings more complexity to the optical responses of the plasmonic nanostructures. Besides, the synthesis of these novel structures deepens our understanding of the crystal growth mechanisms and light-matter interaction. In this dissertation, we discuss the tuning of optical properties of plasmonic nanoparticles through morphology control, magnetic manipulation, and exploring unconventional materials for the plasmonic solar-energy conversion.In the aspect of morphology control, we achieved island growth of Au on Au nanostructures by introducing lattice mismatch through a thin layer of Pd coating on the substrate. The location of the islands can be controlled by changing the distribution of Pd, and the island features including size, distance, and wetting degree of the islands can be systematically controlled. In the aspect of the dynamic orientational control of anisotropic nanoparticles, plasmonic/magnetic nanocomposites were fabricated, and the magnetic tuning of the nanoparticles was achieved. In this dissertation, we broke the connection between the morphology of the plasmonic and the magnetic component, which was a major challenge in the synthesis of plasmonic/magnetic nanocomposites since it limited the choice of both plasmonic and magnetic components. Furthermore, alternative plasmonic metals were explored, and we demonstrated the potential and advantages of Ni in the solar steam generation performance. A high energy conversion efficiency was achieved by combining the plasmonic property of Ni and broadband absorption of C. The magnetic response of Ni enabled the bottom-up fabrication of microstructures, further improving the solar steam generation performance of the device.