前驱液pH值对2ZnO·2.2B2O3·3H2O∶Eu3+荧光粉发光性能的影响

采用水热法,通过氨水调节前驱液的pH值,制备了一系列2ZnO.2.2B2O3.3H2O∶Eu3+样品。对所制备的样品进行X射线衍射和荧光光谱分析。研究结果表明:前驱液的pH值影响2ZnO.2.2B2O3.3H2O的结晶程度,在中性条件下制备的样品结晶度最好。当前驱液的pH=5.7时,激发光谱中的Eu-O电荷迁移带的峰位波长最大(262 nm),这可能是由于在此条件下合成的样品中Eu-O键长最长。发射光谱表明:当前驱液的pH>5.7时,Eu3+的发射光谱中的红橙比(I614/I589)随pH值的增大而增大,且当前驱液的pH值在5.7～6.9区间,红橙比(I614/I589)随pH值的增大的速率要比pH值在6.9～9.3之间增加的速率要快。另外,随着pH值的增大,样品的发光强度呈先增大后减小的变化趋势。当前驱溶液pH=8.1时,样品的发光强度最大。

Effect of pH Value of Precursor Solution on the Luminescent Properties of 2ZnO·2.2B2O3·3H2O∶Eu3+ Phosphor

The samples of 2ZnO·2.2B2O3·3H2O: Eu3+ were prepared by hydrothermal method by adjusting the pH value of precursor solution with the ammonia.The crystal phase and luminescent properties of the samples were characterized by X-ray diffraction(XRD) and fluorescence spectrometer.The results of XRD analysis showed that the degree of crystallization of the samples was influenced by the concentration of pH value in precursor solution.The samples were crystallized best when the pH value was around 7.The excitation spectra showed that the charge transfer band of Eu-O located at 262 nm when pH=5.7.This may be due to the band length of Eu-O which is the longest when pH=5.7.The intensity ratio of the emission bands at 614 nm and 589 nm(I614/I589) increased as the pH value(pH>5.7) increasing.Meanwhile,the ratios of I614/I589 of the samples synthesized in the condition of pH=5.7-6.9 increased faster than samples synthesized in the condition of pH=6.9-9.3.The emission spectra showed that the emission intensity of Eu3+ of the sample synthesized at pH=8.1 was the strongest.