基于Sm^(3+)敏化的红色荧光粉Na_(5)Y(MoO_(4))_(4)∶Eu^(3+)发光性能研究

Study on the luminescent properties of red phosphor Na_(5)Y(MoO_(4))_(4)∶Eu^(3+)based on Sm^(3+)sensitization

采用高温固相法制备了一系列新型Na_(5)Y _(1-x)(MoO_(4))_(4)∶x Eu^(3+)(x=0~0.14)和Na_(5)Y_(0.9)-y(MoO_(4))_(4)∶0.1Eu^(3+),y Sm^(3+)(y=0~0.08)红色荧光粉,并对Na_(5)Y _(1-x)(MoO_(4))_(4)∶x Eu^(3+)(x=0~0.14)和Na_(5)Y_(0.9)-y(MoO_(4))_(4)∶0.1Eu^(3+),y Sm^(3+)(y=0~0.08)的物相结构、发光性能、热稳定性、荧光寿命等性能进行了研究。结果表明,在单掺Eu^(3+)的条件下,Na_(5)Y _(1-x)(MoO_(4))_(4)∶x Eu^(3+)(x=0~0.14)荧光粉在395nm紫外光激发下,发射出峰值波长在615nm的强红光,其掺杂浓度为x=0.1,样品的发光强度最高。进一步探究Sm^(3+)对Eu^(3+)在Na_(5)Y _(1-x)(MoO_(4))_(4)∶x Eu^(3+)(x=0~0.14)中的敏化增强作用。通过研究该样品不同Sm^(3+)掺杂浓度下的荧光发射谱,发现Sm^(3+)敏化增强的最佳掺杂浓度为y=0.04;相较于单掺Eu^(3+)的样品,Sm^(3+)敏化后的样品其发光强度为原来的113.8%。Sm^(3+)敏化后的样品存在能量传递现象,能量传递机制为Eu^(3+)与Sm^(3+)之间的电偶极-电偶极相互作用。温度相关荧光发射谱实验结果表明Na_(5)Y_(0.86)(MoO_(4))_(4)∶0.1Eu^(3+),0.04Sm^(3+)具有较好的热稳定性,在437K时荧光发射强度约为室温时的70%左右,而Na_(5)Y_(0.9)(MoO_(4))_(4)∶0.1Eu^(3+)在437K时的荧光发射强度约为室温时的68%左右。因此,Sm^(3+)敏化的Eu^(3+)掺杂Na_(5)Y(MoO_(4))_(4)荧光粉在白光LED领域中具有较大的应用可能性。

A series of novel Na_(5)Y _(1-x)(MoO_(4))_(4)∶x Eu^(3+)(x=0~0.14)and Na_(5)Y_(0.9)-y(MoO_(4))_(4)∶0.1Eu^(3+),y Sm^(3+)(y=0~0.08)red phosphors were prepared by a high-temperature solid-phase method.The phase structure,luminescence properties,thermal stability,and fluorescence lifetime of Na_(5)Y _(1-x)(MoO_(4))_(4)∶x Eu^(3+)(x=0~0.14)and Na_(5)Y_(0.9)-y(MoO_(4))_(4)∶0.1Eu^(3+),y Sm^(3+)(y=0~0.08)were investigated.The results showed that the Na_(5)Y _(1-x)(MoO_(4))_(4)∶x Eu^(3+)(x=0~0.14)phosphor emitted strong red light with a peak wavelength at 615nm under the excitation of UV light at 395nm under the condition of single doping of Eu^(3+),and the optimum doping concentration of x=0.1 resulted in the highest luminescence intensity of the sample.The sensitization enhancement effect of Sm^(3+)on Eu^(3+)in Na_(5)Y _(1-x)(MoO_(4))_(4)∶x Eu^(3+)(x=0~0.14)was further explored.The fluorescence emission spectra of the sample with different Sm^(3+)doping concentrations were investigated,and it was found that the optimum doping concentration for the sensitization enhancement by Sm^(3+)was y=0.04;the luminescence intensity of the Sm^(3+)-sensitized sample was 113.8%of that of the original sample compared with that of the sample doped with Eu^(3+)alone.There was an energy transfer phenomenon in the Sm^(3+)sensitized samples,and the energy transfer mechanism was an electric dipole-electric dipole interaction between Eu^(3+)and Sm^(3+).The temperature-dependent fluorescence emission spectra indicated that the Na_(5)Y_(0.86)(MoO_(4))_(4)∶0.1Eu^(3+),0.04Sm^(3+)samples had good thermal stability,and the fluorescence emission intensity at_(4)37K was about 70%of that at room temperature,while the fluorescence emission intensity of the Na_(5)Y_(0.9)(MoO_(4))_(4)∶0.1Eu^(3+)sample at_(4)37K was about 68%of that at room temperature.Therefore,the Sm^(3+)-sensitized Eu^(3+)-doped Na_(5)Y(MoO_(4))_(4)phosphors have a large potential for application in the field of WLEDs.