采用高温固相法制备了Ca9Al(PO4)7:Eu^2+蓝色荧光粉,研究了Ca9Al(PO4)7:Eu^2+的发光、浓度猝灭及温度稳定性.Ca9Al(PO4)7:Eu^2+的激发光谱覆盖200~350nm紫外区;发射光谱为一主峰位于445nm的宽谱,对应Eu2+的4f65d1→4f7特征跃迁.研究发现,随Eu2+掺杂量的增大,Ca9Al(PO4)7:Eu^2+的发射强度呈现先增大、后减小的变化趋势,最大发射强度对应的Eu2+掺杂量为0.01,即存在浓度猝灭效应,对应的机理为电偶极-电偶极相互作用;依据晶格常数,得出临界距离为2.297nm.在25~300℃范围内改变光谱测量温度,发现温度升高到150℃时,Ca9Al(PO4)7:Eu2+的发射强度变为25℃时的81.0%,对应的激活能为0.268eV,说明材料具有较好的温度稳定性.
Ca9Al(PO4)7:Eu^2+ blue emitting phosphor was synthesized by high temperature solid state method. Luminescence, concentration quenching and thermal stability of Ca9Al(PO4)7:Eu^2+were investigated. Excitation spectrum of Ca9Al(PO4)7:Eu^2+ extended from 200 nm to 350 nm. Under an ultraviolet excitation,Ca9Al(PO4)7:Eu^2+ showed a broad emission band with a maximum at 445 nm, which corresponded to 4f6^5d^1→4f^7 transition of Eu^2+. Emission intensities of Ca9Al(PO4)7:Eu^2+ were influenced by Eu^2+ concentration, and they enhanced with increasing Eu^2+ concentration, and reached a maximum value at 0. 01 Eu^2+ , then decreased with further increasing Eu^2+ concentration because of concentration quenching effect. The concentration quenching mechanism was verified to be dipole-dipole interaction. According to crystal structure data, critical distance can he obtained to be 2. 297 nm. The emission intensity of Ca9Al(PO4)7:Eu^2+ as a function of temperature was explored. When temperature turned up to 150 ℃, the emission intensity of Ca9Al(PO4)7:Eu^2+ was 81.0% of the initial value at 25 ℃, and the corresponding activation energy was calculated to be 0. 268 eV, which could prove the thermal stability of Ca9Al(PO4)7:Eu^2+.