Effects on atmospheric conditions on the luminescent properties of lanthanide compounds

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With the increasing presence of light emitting diodes (LEDs) for general lighting applications and as display lighting, there is a market for LEDs with high color rendering. As either electroluminescent materials or phosphors, lanthanides can be used to afford color tunable LEDs because of their high stokes shift and sharp emission spectra. High color rendering is possible through the development of trichromatic systems. For example, for a trichromatic RGB based LED, the complex can contain two lanthanides including Eu3+ as the red emitter, Tb3+ as the green emitter and an organic ligand as the blue emitter. Our group has used lanthanide beta-diketonate ligands to obtain lanthanide complexes with varying color emissions. Based on current work in our group, it has been found that lanthanide beta-diketonate complexes have luminescence characteristics that can also change with reaction conditions. The effect of moisture will be investigated using mechanochemical synthesis of both hydrated and anhydrous lanthanide complexes in both air and nitrogen atmosphere. The physical and spectroscopic properties of these complexes will be analyzed using DSC, FTIR, UV-Vis and fluorimetry to determine how ambient moisture affects color rendering in lanthanide-based LEDs. Based on initial studies, it is believed that the ambient moisture present during the reaction can affect the luminescence color via the presence of OH bonds that can dampen certain radiative processes leading to different color emissions depending on the degree of hydration.