Y_(2-x-y)Bi_(x)Eu_(y)MgTiO_(6)荧光粉的发光特性研究

Luminescence characteristics of Y_(2-x-y)Bi_(x)Eu_(y)MgTiO_(6)phosphors

双钙钛矿因其结构灵活、易于掺杂、热稳定性好等优点,成为近几年的研究热点。稀土掺杂双钙钛矿基质材料的光致发光研究常见报道,但和热释光有关的研究较少。本文采用高温固相法合成了Bi^(3+)和Eu^(3+)共掺的Y_(2-x-y)Bi_(x)Eu_(y)MgTiO_(6)(0≤x<1,0≤y<1)系列样品,并测量了样品的X射线衍射谱(X-ray Diffraction,XRD)、光致发光光谱(Photoluminescence,PL)和热释光谱(Thermoluminescence,TL)。XRD分析表明:样品的晶体结构均为单斜晶系P2_(1)/n,Bi^(3+)和Eu^(3+)通过替代Y^(3+)而掺入Y_(2)MgTiO_(6)中;PL表明:样品最佳掺杂浓度为x=0.01、y=0.20,该样品在620 nm附近有较强的红光发射(对应Eu^(3+)的^(5)D_(0)→^(7)F_(2)跃迁),并伴有长余辉;测定不同浓度Bi^(3+)和Eu^(3+)掺杂样品的TL曲线也观察到Y_(1.79)Bi_(0.01)Eu_(0.20)MgTiO_(6)的热释光灵敏度最高,样品在510 K和610 K附近有两个显著的TL峰;热释光谱比荧光谱更为丰富,Eu^(3+)的^(5)D_(0)→^(7)F_(J)(J=1,2,3,4)跃迁均可被观测到,样品的TL光强与辐照剂量在2~1000 Gy范围内具有良好的线性关系。采用不同预热温度(T_(m)-T_(stop))和计算机拟合(Glow Curve Deconvolution,GCD)两种方法分析样品的TL动力学参数,发现样品中热释光陷阱深度从0.80 eV延伸到1.40 eV。上述测试和分析结果表明:热释光谱比荧光谱更为丰富;Y_(1.79)Bi_(0.01)Eu_(0.20)MgTiO_(6)荧光粉可作为大剂量检测的热释光剂量计材料。

[Background]Double perovskites have become a research hotspot in recent years due to their flexible structure,easy doping,and good thermal stability.Photoluminescence(PL)of rare-earth-doped double perovskite materials has been frequently reported,but few studies on thermoluminescence(TL)have been conducted.[Purpose]This study aims to investigate the TL characteristics of Y_(2-x-y)Bi_(x)Eu_(y)MgTiO_(6)(0≤x<1,0≤y<1)phosphors.[Method]Bi^(3+)and Eu^(3+)co-doped Y_(2)MgTiO_(6)samples were synthesized by a high-temperature solid phase method,and the X-ray diffraction(XRD),PL,and TL of the samples were measured.[Results]XRD analysis results show that the crystal structures of all samples are monoclinic P2_(1)/n,and Bi^(3+)and Eu^(3+)are doped into Y_(2)MgTiO_(6)by substituting Y^(3+).The PL results show that Y_(1.79)Bi_(0.01)Eu_(0.20)MgTiO_(6)has a strong red emission near 620 nm(corresponding to the^(5)D_(0)→^(7)F_(2)transition of Eu^(3+)),which is accompanied by a long afterglow.The TL curves of the samples doped with different concentrations of Bi and Eu ions show that Y_(1.79)Bi_(0.01)Eu_(0.20)MgTiO_(6)has the highest TL sensitivity,and the samples exhibits two significant TL peaks near 510 K and 610 K.The TL spectrum is more abundant than the fluorescence spectrum,and the^(5)D_(0)→^(7)F_(J)(J=1,2,3,4)transition of Eu^(3+)can be observed.The TL intensity of the sample has a good linear relationship with the irradiation dose in the range of 2~1000 Gy.The TL kinetic parameters of the samples are analyzed using two methods under different preheating temperatures(T_(m)and T_(stop))and glow curve deconvolution.The analysis results show that the depth of the TL trap in the sample extends from 0.80 eV to 1.40 eV.[Conclusions]The results of this study indicate that the TL spectrum is richer than the PL spectrum and that Y_(1.79)Bi_(0.01)Eu_(0.20)MgTiO_(6)may be used as TL dosimeter material for large dose detection.