470553 Controlling the Absorption Spectra of Transition Metal Doped Nanostructures
Specifically, 5-10 nm thick thin films of ZnO, TiO2, and SiO2 will be synthesized via common sol-gel techniques. Various first row transition metals, i.e., Cr, Mn, and Co, are readily incorporated into the film at various concentrations through the incorporation into the sol-gel solution film deposition. High temperature annealing was performed after film deposition to convert each material to the final oxide form, including anatase and rutile TiO2. The three host materials where chosen to ensure different absorption spectra for the dopant based on the crystal field strength whereas a film below 10 nm prevents the ion shielding based on the distance from the interface. Nanoparticles approximately 20 nm in diameter and similar compositions were synthesized as an alternative material to the thin films. The dopant ions are seen to be readily incorporated into the polycrystalline thin films are lower concentrations based on X-ray diffraction and photoemission spectroscopy techniques. Absorption and photoluminescence measurements were conducted on all the various materials before and after annealing to quantify the shift in optical properties, indicative of the role of external forces on the luminescent particle. Based on these characterization methods it is possible to extract the local crystal field strength in order to predict the extent of absorption and emission shifts that are possible under stronger applied fields, such as electric and magnetic fields.
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