Eu3+ doped yttrium oxide nano-luminophores from laser synthesis

Nano-sized Y2O3:Eu phosphors were obtained from laser synthesis at a production rate of 25 g/h, the initial product consisting of purely monoclinic material, of primary particle sizes of 20-30 nm as could be shown by powder X-ray diffraction, TEM and BET. Despite a large amount of surface adsorbed water and O-H groups, and peculiarly, nitrous oxide species, as shown by mass spectrometer coupled thermoanalysis/thermogravimetry and FTIR, the luminescence efficiency still amounted to approximately 19% relative to bulk Y2O3:Eu. On thermal conversion at 900 °C, the transformation to cubic Y2O3:Eu, now yielding particles of approximately 60 nm appeared to be complete and had an efficiency of about 68%, however, an efficiency of 93%, approaching that of bulk Y2O3:Eu, was obtained on annealing at 1200 °C. Significantly, a rapid re-formation of carbonates takes place on the calcined samples also.