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Samarium doped LaYO3 nanocrystalline phosphor powders are obtained by polymer complex solution method. Stoichiometric quantities of La2O3, Y2O3 and for dopant ions Sm2O3 were dissolved in hot nitric acid. Polyethylene glycol was added in solutions in 1:1 mass ratio to corresponding metal nitrates to form gel. The gel is combusted and annealed at 800 °C for two hours to form nanopowder samples. Crystalline structure and phase purity is checked by X-ray diffraction and show that this material is synthesized in cubic bixbyite type structure for the first time. Luminescence properties of Sm3+ doped LaYO3 exhibited characteristic orange-red emission coming from the intra-4f-shell 4G5-2→6HJ electron transitions with emission decay of 1.5 ms. Energy level positions are derived from emission and excitation spectra. [ABSTRACT FROM AUTHOR]

We prepared Eu3+- and Sm3+-doped YNbO4 phosphor powders using a simple solid-state reaction method and examined their photoluminescence properties in order to investigate the possibility for their usage in phosphor thermometry. Photoluminescence measurements were performed in the temperature range 303–773K, and the fluorescence intensity ratio of the paired emissions lines was studied as a function of temperature. The results have shown that YNbO4:Eu3+ possesses the absolute sensitivity of approximately 3Ã?10−3 K−1 at about 700K, while relative sensitivity changes within the range of 0.5–2.7%K−1. YNbO4:Sm3+ has the maximum sensitivity of around 7Ã?10−4 K−1 at about 700K with the relative sensitivity of 0.43%K−1 around 500K. Calculated temperature sensitivities of samples show that these materials have a good potential for the development of thermographic phosphors. Experimental lifetime measurements recorded at 303–773K were fitted using a temperature dependent charge transfer model, TDCT. This model yields good agreement between experimental and fitted lifetime data. The sample crystalline structure is confirmed by XRD measurements. [ABSTRACT FROM AUTHOR]