Total Precipitation Synthesis Of Sr <sub> 2 </ Sub> Of Ceo <sub> 4 </ Sub> And Sr <sub> 2 </ Sub> Of Ceo <sub> 4 </ Sub>: Re (re = Eu, Of Sm, Er, Gd) Materials, Luminescent Properties

With the rapid developments of new technology, luminescent materials science and technology have attracted much attention. Today, luminescent materials play important roles in many fields of the society, and the cognition and research work on them have capacious academic value and practical application. The accession of rare earth elements brings the remarkable improvement to the luminescent materials, being a bout of revolution relative to the traditional luminescent materials. Thus the rare earth luminescent materials become the research focus more and more.Sr₂CeO₄ is a new and efficient blue emission powder phosphor, It can also be regarded as the host material besides giving out light itself. Co-precipitation has been used to prepare the precursor of Sr₂CeO₄ via different precipitants. However the fluorescent performances of Sr₂CeO₄ synthesized by different precipitants were not compared.In this paper, we prepared Sr₂CeO₄ and Sr₂CeO₄: RE (RE= Eu, Sm, Er, Gd) by co-precipitation.Here, the synthesis of Sr₂CeO₄ powders through chemical co-precipitation using ammonium oxalate or ammonium carbonate as precipitants was reported. The optimum conditions to prepare Sr₂CeO₄ phosphor powder should use the carbonate precursor, and raise the heating temperature to 1250°C.Ce4+â†'Eu³⁺ energy transfer exists in Sr₂CeO₄: Eu³⁺. Under the excitation of UV light, with the increase of the Eu³⁺ concentration form low (1 mol%) to high (10 mol%), the emission light changes from blue-white to red-white. In addition, the energy transfer phenomenon of Gd³⁺â†'Eu³⁺ in Sr₂CeO₄: Eu³⁺,Gd³⁺ was observed. When the Gd³⁺ concentration is 3 mol%, the optimum Eu³⁺ luminescent effect in Sr₂CeO₄: Eu³⁺, Gd³⁺ is achieved.In the experiment of Sr₂CeO₄: Sm, we confirm the optimum heating temperature and the Sm³⁺ concentration. In spite of the sintering period only takes 3 h, the intensity of emission spectra is twice as that of which was synthesized by conventional high temperature solid state reaction and sintered for 30 h.All the time, Er³⁺ has been concerned abroad due to up-conversion emissions. Sr₂CeO₄: Er phosphor was prepared, and green up-conversion emissions (547 nm) and red up-conversion emissions (644 nm) was observed. When the Er³⁺ concentration is 2 mol%, the sample has the best effect of up-conversion emissions.The novel studies of the work are in the following:(1) We compared the fluorescent effect of Sr₂CeO₄ synthesized by different precipitants and confirmed the optimum condition of preparation.(2) Although the heat-treatment period was decreased greatly as compared with conventional solid state reaction, the luminescence efficiency was evidently improved. No doubt, they are suitable to the application of luminescent materials.