摘要
在还原气氛下采用高温固相法合成了Eu2+激活的硅酸盐基质白光LED用发光粉,运用扫描电子显微镜和荧光分光光度计分别对发光粉的形貌和激发、发射光谱进行了表征,并对其与YAG发光粉的封装特性进行了对比研究。结果表明,合成的硅酸盐基质白光LED用发光粉其激发光谱覆盖范围宽。采用不同波段的LED芯片进行封装时,和YAG发光粉相比,其色坐标、显色指数和流明效率波动不大,尤其是流明效率波动仅在8%左右,而且其老化性能也和YAG发光粉差别不大。对其和YAGLED的相对发射光谱研究表明,硅酸盐更适合暖白光LED的封装,硅酸盐发光粉粒径与封装流明效率规律变化的研究结果表明,较大粒径的硅酸盐发光粉有可能在大功率LED上有潜在的应用前景。
Considering the growing importance of energy saving and environmental friendliness, solid-state lighting is emerging as a highly competent field and a possible alternative to existing lighting technologies. Recently, a blue LED combining with a yellow emitting YAG: Ce phosphor was used mostly to make whitelighting LED, however, as the high synthesis temperature of YAG phosphor, poor color quality due to the serious scarcity of red light, a novel phosphor is rather needed. An Eu-activated silicate-based phosphor for WLED was prepared by solid-state reaction (SSR) under reductive atmosphere. The morphology of the phosphor powder was observed by means of scanning electronic microscope. The excitation and emission spectra were measured by F-4500 spectrometer using a Xe-lamp as an excitation source. And the encapsulation characteristics of silicate-based phosphor were comparatively studied with that of YAG phosphor. The results showed that the as-synthesized silicate-based phosphor has homogenous particle size of about 15 μm and broad excitation band. When the as-synthesized phosphor and YAG were encapsulated to blue LED chips with different emission wavelength, the chromaticity coordinate, color-rendering index and luminous efficiency fluctuated a little; especially the luminous efficiency only fluctuated about 5% in comparison with YAG. However, when YAG phosphor was encapsulated to blue LED chip with emission wavelength longer than 462.5 nm, its luminous efficiency decrease remarkably due to its narrow excitation spectra. The comparison results of relative emission spectra of silicate and YAG LED indicated silicate phosphor is more suitable for the encapsulation of warm white LED than YAG phosphor. And the results of particle size showed silicate phosphor have potential application for high power LED. The aging performance of silicate phosphor is better than that of YAG phosphor. In conclusion, the as-synthesized silicate-based phosphor is a novel phosphor for white LED, having a broad excitation band and ex
出处
《发光学报》
EI
CAS
CSCD
北大核心
2009年第4期503-508,共6页
Chinese Journal of Luminescence
基金
国家"863"计划(2004AA001530
2006AA03A137)资助项目
关键词
硅酸盐
发光粉
白光LED
封装
silicate
phosphor
white-light-emitting LED
encapsulation