CaMoO4:Eu3+纳米荧光粉的尺寸调控及光学性能研究

Size control and optical properties of CaMoO4:Eu3+ nanophosphors

采用水热法制备了CaMoO4:Eu3+纳米荧光粉.研究了反应温度、反应时间和Eu3+掺杂浓度对CaMoO4:Eu3+纳米晶的颗粒尺寸以及光学性能的影响.利用XRD、SEM、FT-IR、UV-Vis和PL对所得样品的相结构、形貌、光学吸收以及发光性能进行了表征.研究结果表明:所合成样品均为四方晶系白钨矿结构的CaMoO4纳米晶;一方面,随着水热反应温度的降低或者反应时间的缩短,CaMoO4:Eu3+纳米晶都表现出尺寸减小的趋势,荧光强度逐渐减弱,样品的紫外可见光吸收带边发生蓝移;另一方面,随着Eu3+掺杂浓度的增加,CaMoO4:Eu3+纳米晶的颗粒尺寸逐渐减小,样品的紫外可见光吸收带边出现红移.同时,在275nm的光激发下,CaMoO4:Eu3+荧光粉在614nm处的5D0→7F2跃迁具有最高的荧光强度,观察到红光发射,且发现其荧光猝灭摩尔浓度为6%.

CaMoO4:Eu3+ nanophosphors with different concentrations of Eu3+ were prepared by hydrothermal method. A series of experiments were conducted to investigate the effect of reaction temperature, time, and Eu3+ doping concentration on the nanoparticle size and optical properties. The phase structure, morphology, and optical property of the samples were systematically characterized by XRD, SEM, FT-IR, UV-Vis, and PL spectra. Results indicated that the synthesized red phosphors of CaMoO4:Eu3+ were scheelite structure. On the one hand, with the decline of hydrothermal reaction temperature or reaction time, CaMoO4:Eu3+ nanocrystals showed a decreasing tendency of nanocrystals sizes, resulting in the gradually decline of the luminous intensity and the occurrence of bule shift on the UV-Vis absorption edge. On the other hand, with the increase of Eu3+ doping concentration, the average particle size of CaMoO4:Eu3+ nanocrystals decreased and the UV-Vis absorption band of the samples had red shift. Moreover, CaMoO4:Eu3+ nanophosphors could be excited by a wavelength of 275 nm light and exhibited a strong red emission at 614 nm of 5D0→7F2, showing the fluorescence quenching molar concentration of Eu3+ at 6%.