SiO_2包覆CaAl_(12)O_(19)∶Mn^(4+)荧光粉的温度特性

Temperature Dependence of Silica Coated Ca Al_(12)O_(19)∶Mn^(4+) Phosphor

采用溶胶-凝胶法制备无定型Si O2包覆Ca Al12O19∶Mn4+荧光粉,对样品进行XRD、TEM-EDS、FTIR以及发光性能分析。实验结果显示,包覆后样品的XRD图在22°左右出现了一个无定型二氧化硅特征宽峰,且随着Si O2包覆量的增加,该衍射峰的强度增强;FTIR分析发现样品包覆后存在明显的Si-O-Si键。Si O2包覆后Ca Al12O19∶Mn4+样品的激发和发射光谱峰值强度有所减弱;当包覆比为10%时,所制备样品的光辐照稳定性显著提高。通过对样品80~400 K变温光谱的分析表明,其发射光强度显现先增强后减弱的变化规律;与空白样品相比,二氧化硅包覆后的样品具有更高的热激活能。

The Ca Al12O19∶Mn4＋ phosphors coated with amorphous SiO2 were prepared by means of sol-gel method and were characterized by XRD, TEM, EDS, FTIR and photoluminescence spectra. The X-ray diffraction results showed that the as-prepared powders appeared an amorphous silica feature wide peak around 22° which showing increasing intensity with increasing amount of coated SiO2. FTIR analysis found obvious Si-O-Si band of coated samples. The TEM demonstrated that the particle size was about 3-6 μm. After coated, the intensity of excitation and emission spectrum were reduced. It showed that the photostability of the 10% silica coated sample can be effectively improved with minimum loss of emission intensity. The temperature-dependent emission spectra of 50% silica coated and the uncoated samples were investigated from 80 to 400 K, the results found that an anti- quenching phenomenon that the emission intensities increased then decreased at increased temperature, and the coated samples has higher thermal activation energy compared with uncoated sample.