(307f) Colloidal Synthesis and Magnetic and Optical Properties of Shape-Controlled Multi-Element-Doped Zinc Oxide Nanostructures

Transition-metal-doped zinc oxide nanocrystals are of interest because of their tunable optoelectronic properties, stability, and durability. Even though these topics have been widely investigated, the broad space of compositions and properties opened up by multi-element doping of nanocrystals and impacts of multi-element doping on size, shape, composition, and resulting opto-electronic and magneto-optic properties remains relatively unexplored. Herein, we report single-phase multi-element doped zinc oxide nanostructures building from a hexagonal platelet motif. We simultaneously dope with the magnetic elements Fe, Co, and Ni, and then explore how the additional doping of other metal atoms affects morphology and properties. For example, co-doping with germanium or aluminum led to thick nanoplatelets, co-doping with indium produced nearly two-dimensional hexagonal platelets and co-doping with chromium leds to tetragonal nanostructures. Despite the presence of Fe, Co, and Ni, none of these zinc oxide nanostructures exhibited ferromagnetic behavior but paramagnetic behavior at low temperatures and superparamagnetic behavior at room temperature. We also studied the magneto-optic properties of all these multi-elements doped zinc oxides. Starting from Fe-Co-Ni doped zinc oxide, doping with additional elements produced different magnetic circular dichroism (MCD) responses in different absorbance wavelength regions under fields up to ±1.5 T.