Energy Transfer in Sm³⁺:YAlO₃

The luminescent properties of lanthanide doped materals find use as phosphors for lighting, scintillators, and lasers media. Yttrium aluminum perovskite (YAP) has excellent thermal, mechanical, and optical properties and is a less studied phase in the Al₂O₃-Y₂O₃ system compared to the more well-known Y₃Al₅O₁₂ (YAG). Because of the resonance overlap between different electronic transitions in the Sm³⁺ impurity ions, radiationaless energy transfer occurs between impurities at higher impurity concentrations. We report energy transfer studies on combusion synthesized samples. The sample crystal structure was characterized by x-ray diffraction and the impurity ion site identified through laser induced fluorescence spectroscopoy. Lifetime measurements were carried out and fitted using the Inokuti-Hirayama model. Parameters from the fits were used to compare the energy transfer in our small-scale phosphors to single crystals. The results demonstrate that liquid-phase mixing of host and impurity ions produces materials with well distributed impurity ions and that energy transfer between ions decreases in fine grain powders compared to bulk materials.