| dc.description.abstract | Nanomaterials offer a unique platform to study the effect of morphology, light polarization, as well as quantum confinement on their photophysical properties. In this dissertation, two classes of nanomaterials – plasmonic gold nanostructures and semiconducting lead-halide perovskite quantum dots and their photophysical properties were explored.
In the first part of this work, plasmonic gold nanostructures subjected to circularly polarized illumination will generate static magnetic field as well as circular drift current. The light-induced static magnetic field in gold nanoparticle was measured for the first time, using time-resolved pump-probe Faraday rotation spectroscopy. The magnetization dynamics was instantaneous and coherent to incident light, reflecting its orbital angular momentum origin. Moreover, the circular drift current generated only under elliptical and circular polarized illumination results in a fundamental modification of electrical conductivity and plasmon dephasing time. Raman thermometry and photothermal effect were used to probe this modulation in a gold nanodisks array, and a qualitative agreement with our prediction was demonstrated.
The second part of this work is focused on the photoluminescence properties of strongly quantum confined CsPbBr3 quantum dots, and the effect of their size and environment temperature. In contrast to other conventional semiconductor nanocrystals, such as II-VI, the photoluminescence peak position of CsPbBr3 quantum dot was redshifted as the temperature decreased. In addition, the photoluminescence linewidth showed a strong size- and temperature- dependence, which can be attributed to strong coupling to both longitudinal optical phonon and vibrational mode of ligands on the surface of quantum dots. | en |
