Low-temperature synthesis of red-emitting nanostructured : phosphor

An Eu3+-doped red emitting nanostructured La2O2S2 phosphor was synthesized using a combustion process at 230 °C. The as-synthesized and heat-treated phosphors were characterized by a number of techniques, including scanning electron microscope to determine morphology and composition. The as-synthesized particles were porous with agglomerated particles of ∼100 nm. X-ray diffraction (XRD) data showed that the crystallite size was 17.5 nm and pattern matched with tetragonal La2O2S2. The lattice parameter was slightly smaller and consistent with the formation of La2−xEuxO2S2, where x reflects the concentration of Eu (0%–14.4%). The photoluminescence quantum yields of as-synthesized and heat-treated powder phosphors were found to be ∼0% and 25%, respectively (excitation wavelength of 395 nm).