Different fluxes were used to synthesize long persistence phosphors, calcium sulfides activated by Eu 2+ and Tm 3+ , by convenient solid state method. The phosphor using NH 4F as a flux has good crystallini...Different fluxes were used to synthesize long persistence phosphors, calcium sulfides activated by Eu 2+ and Tm 3+ , by convenient solid state method. The phosphor using NH 4F as a flux has good crystallinity and large particle size, its stability against water and other atmospheric components is enhanced, and its afterglow is longer and fluorescent intensity is more intense than those of the phosphor using NH 4Cl as flux. Their PL intensities varied with time in moist air were measured, no remarkable change was found for those prepared with NH 4F flux in contrast with NH 4Cl as flux. So using NH 4F as flux is a good method to enhance the stability of alkaline earth sulfides.展开更多
The CaS∶Eu^(2+), Sm^(3+) powders were prepared by high-temperature solid method in a reducing atmosphere. The influences of temperature and fired-time on properties of samples were studied. XRD analysis shows that cr...The CaS∶Eu^(2+), Sm^(3+) powders were prepared by high-temperature solid method in a reducing atmosphere. The influences of temperature and fired-time on properties of samples were studied. XRD analysis shows that crystal structure of CaS has formed at 700 ℃. Spectrum analysis results show that the samples which were stimulated by 980 nm laser after excited by ultraviolet lamp emit red luminescence peaking at 649 nm.展开更多
采用CaxSi合金前驱物和Eu B6常压氮化制备了Ca Al Si N3∶Eu2+氮化物红色荧光粉。研究了不同烧结温度、添加助熔剂及二次烧结对发光性能的影响。通过扫描电子显微镜(SEM)、X射线衍射(XRD)、荧光分光光度计对发光材料的形貌、晶体结构、...采用CaxSi合金前驱物和Eu B6常压氮化制备了Ca Al Si N3∶Eu2+氮化物红色荧光粉。研究了不同烧结温度、添加助熔剂及二次烧结对发光性能的影响。通过扫描电子显微镜(SEM)、X射线衍射(XRD)、荧光分光光度计对发光材料的形貌、晶体结构、发光性能与热稳定性进行了研究。分析结果表明:通过合金前驱物常压氮化法得到的氮化物荧光粉具有Ca Al Si N3结构,空间群为Cmc21。Ca Al Si N3∶Eu2+红色荧光粉的最佳烧结温度为1 550℃。添加质量分数为6%的Sr F2助熔剂后,荧光粉发光强度的提升效果最好。添加6%Sr F2助熔剂及二次烧结后得到的荧光粉的晶粒生长更加完整,颗粒度明显改善,发射光谱的相对强度也明显提高,比未加助熔剂单次烧结的荧光粉相对强度提高了近一倍。将发射峰位在640 nm的Ca0.98Al Si N3∶0.02Eu2+红色荧光粉应用在白光LED的封装中,获得了色温为3 109 K、显色指数为92.5以及色温为4 989K、显色指数为95.8的高显色白光LED,说明本文合成的氮化物红色荧光粉可以实现暖白光和正白光高显色的白LED发光器件。展开更多
文摘Different fluxes were used to synthesize long persistence phosphors, calcium sulfides activated by Eu 2+ and Tm 3+ , by convenient solid state method. The phosphor using NH 4F as a flux has good crystallinity and large particle size, its stability against water and other atmospheric components is enhanced, and its afterglow is longer and fluorescent intensity is more intense than those of the phosphor using NH 4Cl as flux. Their PL intensities varied with time in moist air were measured, no remarkable change was found for those prepared with NH 4F flux in contrast with NH 4Cl as flux. So using NH 4F as flux is a good method to enhance the stability of alkaline earth sulfides.
文摘The CaS∶Eu^(2+), Sm^(3+) powders were prepared by high-temperature solid method in a reducing atmosphere. The influences of temperature and fired-time on properties of samples were studied. XRD analysis shows that crystal structure of CaS has formed at 700 ℃. Spectrum analysis results show that the samples which were stimulated by 980 nm laser after excited by ultraviolet lamp emit red luminescence peaking at 649 nm.
文摘采用CaxSi合金前驱物和Eu B6常压氮化制备了Ca Al Si N3∶Eu2+氮化物红色荧光粉。研究了不同烧结温度、添加助熔剂及二次烧结对发光性能的影响。通过扫描电子显微镜(SEM)、X射线衍射(XRD)、荧光分光光度计对发光材料的形貌、晶体结构、发光性能与热稳定性进行了研究。分析结果表明:通过合金前驱物常压氮化法得到的氮化物荧光粉具有Ca Al Si N3结构,空间群为Cmc21。Ca Al Si N3∶Eu2+红色荧光粉的最佳烧结温度为1 550℃。添加质量分数为6%的Sr F2助熔剂后,荧光粉发光强度的提升效果最好。添加6%Sr F2助熔剂及二次烧结后得到的荧光粉的晶粒生长更加完整,颗粒度明显改善,发射光谱的相对强度也明显提高,比未加助熔剂单次烧结的荧光粉相对强度提高了近一倍。将发射峰位在640 nm的Ca0.98Al Si N3∶0.02Eu2+红色荧光粉应用在白光LED的封装中,获得了色温为3 109 K、显色指数为92.5以及色温为4 989K、显色指数为95.8的高显色白光LED,说明本文合成的氮化物红色荧光粉可以实现暖白光和正白光高显色的白LED发光器件。
