笼中阴离子基团对Nd~(3+)掺杂C12A7粉体红外发光的影响

采用自蔓延燃烧法制备了不同Nd3+掺杂浓度的具有笼状结构的12Ca O·7Al2O3(C12A7∶x%Nd3+)粉体材料。在808 nm波长的激发下,观测到了位于887,1 069,1 340 nm附近的3个近红外发射峰,分别归属于Nd3+的4F3/2→4IJ/2(J=9,11,13)跃迁。Nd3+掺杂摩尔分数达到0.5%时,红外光发射较强,且没有观察到杂质相。在H2气氛下对样品进行1 300℃热处理之后,笼中OH-和H-浓度增加,笼子发生畸变,晶粒尺寸变大,样品的结晶性变好。通过在空气下热处理,减少了高能振动基团OH-的数目,进一步增强了近红外光发射。变温光致发光谱测量结果表明,C12A7∶x%Nd3+样品具有较高的热激活能,在红外激光器上有潜在的应用前景。

Effect of Encaged-anion Groups on Infrared Luminescence of C12A7: Nd3+ Powders

C12A7 :x%Nd³⁺ powders with unique nanocaged structure were synthesized by self-propagating combustion method. Upon 808 nm excitation, we can observe three peaks at 887, 1 069, 1 340 nm attributed to the transition ⁴F_3/2→⁴I_J/2(J=9, 11, 13) of Nd³⁺, respectively. When Nd³⁺ mole fraction is 0.5%, the intense infrared luminescence can be obtained and no impurity phase is observed. After the annealing in H₂ ambient, the encaged OH^- and H^- concentrations and the grain size of C12A7 increase and the cages are distorted. The improvement of the crystallinity and the decrease of the non-radiative transition rate can enhance the near-infrared luminescence after the annealing in air. Based on the temperature-dependent emission spectra, the high thermal activation energies are obtained, indicating that C12A7 :x%Nd³⁺ have potential applications in infrared laser.