Optical and structural properties of composites films based on Ce³⁺ -doped yttrium aluminium garnet nanoparticles...

In the present work, attempts have been made to prepare scintillating nanoparticle composite films of Ce³⁺ -doped Y₃ Al₅ O₁₂ (YAG:Ce) embedded in a polystyrene (PS) polymer. A YAG:Ce phosphor has been previously synthesized using the sol-gel method. YAG:Ce-PS composite films of 250 ± 30 μm thickness were prepared using a solvent casting procedure with different PS/solvent concentration and a different mass ratio between nanoparticles of YAG:Ce and PS. X-ray diffraction analysis confirmed that the YAG:Ce powders were successfully prepared. Using thermogravimetric analyses and differential scanning calorimetry, we found that the glass transition temperature (Tg) and thermal degradation were shifted to higher temperatures for composite films relative to pure PS. Photoluminescence showed the yellow emission of the Ce³⁺ -doped YAG phosphors, which was attributed to the 5d→4f transition of Ce³⁺ ion and the intensity of the emissions changed with the mass ratio of the YAG:Ce nanoparticles incorporated in the polymer and with the concentration of the polymer solution.