Eu³⁺，Bi³⁺共掺CaCO₃红色荧光粉材料性能的研究

A Study of Luminescent Properties of CaCO₃:Eu³⁺, Bi³⁺ Red Phosphors

摘要: 以CaCO₃，Eu₂O₃，Bi₂O₃为主要材料，通过水热共沉淀法合成了Eu³⁺和Bi³⁺共掺的碳酸钙。研究发现，Eu³⁺和Bi³⁺共掺的碳酸钙荧光粉在360 nm近紫外光(Bi³⁺激发峰、非Eu³⁺激发峰)的激发下有Eu³⁺的特征发射峰，考虑到Eu³⁺的激发谱和Bi³⁺的发射谱之间存在重叠，该结果说明Eu³⁺和Bi³⁺之间存在的能量传递可提高CaCO₃在红光波段的发光效率。其中，CaCO₃:Eu³⁺, Bi³⁺最强发射峰在593 nm附近处，Eu³⁺的跃迁以磁偶极跃迁5D0~7F1为主，Eu³⁺在晶体场中占据严格的反演中心。随着Eu³⁺含量的增加，Eu³⁺的发射峰相对光强先增大后减小，说明过量的Eu³⁺会导致浓度淬灭。此类红色荧光粉发光效率高，价格低廉，在LED工业方面具有潜在价值。

Abstract: CaCO₃:Eu³⁺, Bi³⁺ are synthesized by the hydrothermal co-precipitation method. Under the ultraviolet light excitation at 360nm, which is the excitation wavelength of Bi³⁺ but not of Eu³⁺, the typical emission peaks of Eu³⁺ are observed. Considering that the excitation spectra of Eu³⁺ and the emission spectra of Bi³⁺ are partially overlapped, these results show that the luminescent efficiency of CaCO₃ phosphors can be improved by the energy transfer from Bi³⁺ to Eu³⁺. The maximal emission peak of CaCO₃:Eu³⁺, Bi³⁺ locates in the vicinity of 593 nm, corresponding to magnetic-dipole transition 5D0→7F1 of Eu³⁺, which confirms that the Eu³⁺ ion locates in a high inversion center. With the increase of the doping concentration of Eu³⁺, the relative light intensity of Eu³⁺ emission peak first enhances then decreases. This can be explained by phenomenon of concentration quenching which occurs when Eu³⁺ doping concentration is too high. This red phosphor material with high efficiency and low price has great potential in the LED industry.