Date of Award
Doctor of Philosophy
Materials Science and Engineering
Tessa Calhoun, Zheng Gai, David Mandrus
Multi-functional materials system such as: two-photon absorption based up-conversion crystals, magnetic/semiconducting hybrid 2D nanoparticles, and hybrid perovskites, have attracted significant research interest due to their exceptional magnetic-electronic-optical properties. However, the study on magneto-optical properties at room temperature with low field in these novel multi-functional materials are still lacking. The fundamental studies on the underlying mechanism of magneto-optical phenomenon based on excited states for these materials are still highly demanded. Magnetic field effects can be utilized as effective experimental tool to analyze spin-dependent processes of multi-functional materials in excited states. This thesis aims to experimentally explore spin-dependent process in excited states for multi-functional materials toward improved performance, by using magnetic field effects and polarized photoexcitation. Chapter 1 presents a basic introduction to magnetic field effects and development of metal-halide perovskites. Chapter 2 demonstrates magnetic field dependent photoluminescence based on multi-photon excitation in rare earth nanocrystals by considering the spin-dependent electric dipoles. Chapter 3 illustrates photoexcitation-controllable magnetization based on magnetic-semiconducting hybrid system by using steady-state pump-probe measurements in magnetic field. Chapter 4 studies the orbit-orbit interaction between polarized photoexcitation generated electron-hole pairs in metal halide perovskites, and its influence on spin mixing process. In chapter 5, the dipole moment effect on light emission properties of metal halide perovskite nanoparticles by using cation doping will be demonstrated. Chapter 6 summarizes a conclusion for entire studies in this dissertation.
Xu, Hengxing, "Magneto-optical Effects in Multifunctional Materials. " PhD diss., University of Tennessee, 2019.
Portions of this document were previously published in journals: SMALL, The Physical Chemistry C.