| Abstract Scope |
Many ionic lanthanides produce strong and distinctive luminescent properties. Typically, lanthanide dopants are present as trivalent ions which resist effects of the local environment of the host material; exhibiting a characteristic luminescent color regardless of the composition it is doped into. However, given a sufficiently reducing environment, select lanthanides can convert into a divalent state. These divalent ions are much more susceptible to ligand field effects; meaning, similar to transition metal color centers, divalent lanthanides may exhibit a wide variety of luminescent colors dependent upon composition of the host material. For example, whereas trivalent europium presents as a scarlet red luminescence; the divalent ion may range from anywhere along the visible spectrum from red to an aqua blue. Notably, compositions of soda lime silicates containing divalent europium were found to exhibit a brilliant “highlighter” yellow-green luminescence. Analysis of the shifts in luminescent wavelength was accomplished by fluorimetry and related spectroscopies. |