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Abstract
Large bandgap materials doped with rare earth ions are currently of great interest as new vacuum UV phosphors for lighting and displays. In this dissertation, we examine several ways to sensitize Gd for application to cross relaxation energy transfer (CRET) and photon cascade emission (PCE). The optical properties of GdF3 doubly doped with Pr and Eu, GdLiF4 doped with Nd, ScPO4 doped with Gd and GdZrF7 doped with Eu are described. The 5d 4f transition of a trivalent rare earth ion is an effective method to sensitize Gd3+. It is still necessary to find a system in which the energy gets to the 6G states of Gd3+ such that quantum cutting with a co-doping of Eu3+ or some other lanthanide can be utilized for quantum cutting. The sensitization with the STE is a very effective means of obtaining good coupling of the VUV excitation to Gd3+. To use STE sensitization of the 6G states of Gd3+ for quantum cutting, it will be necessary to identify materials whose STE emission occurs at even shorter wavelengths than is the case for ScPO4 so that a larger fraction of the energy transfer occurs to the 6G states or even higher-lying states of Gd3+.