用于白光LED稀土Eu掺杂SiAlON基荧光粉的发光性能

Luminescence Property of Eu Doped SiAlON Phosphors for White LEDs

SiAlON基荧光粉因其优异的化学和物理稳定性,成为近年来发光领域的一个研究热点,尤其在LED等领域,受到研究者的热切关注。稀土掺杂SiAlON基荧光粉体有望成为新一代照明光源。由于缺乏青色光发射,往往会造成显色性能不足。本研究通过传统高温固相法合成了β-Si_(5)AlON_(7):Eu荧光粉,采用X射线衍射仪(XRD)、扫描电镜(SEM)、X射线光电子能谱(XPS)等研究了其结构、形貌、元素和价态。通过光谱仪表征了样品的激发光谱以及发射光谱的波长范围并测试了热猝灭性能,发现激发波长覆盖紫外至蓝色光区域,并且发射光谱显示出典型的Eu^(2+)跃迁的宽谱。在300℃下,样品的发射光强度依然可达到室温强度的40%左右,热激活活化能(Ea)达到了3.7 eV,相比较商用YAG:Ce^(3+)(YAG)荧光粉,热稳定性有一定的提升。在与蓝色芯片复合后成功制备了高显色(显色指数Ra=87)的白色发光LED,对应的色温也达到了暖白光范围(CCT=4501 K)。本研究实现了SiAlON基青色发射,获得了热稳定性较为优异的荧光粉,在发光的可持续性能上也比商用YAG有明显优势。

SiAlON-based phosphor has become a research hotspot due to its excellent chemical and physical stability.Especially in the LEDs field,it has received extensive attention in recent years.Rare earth doped SiAlON phosphor is expected to become a new generation of lighting source.However,due to the lack of cyan light emission,the color rendering performance of white-LED(wLED)is often insufficient.In this research,β-Si5AlON7:Eu phosphors were synthesized by the traditional high-temperature solid-state route.The structure,morphology,elements and valence states were examined.The wavelength range of excitation spectrum and emission spectrum of Si5AlON7:Eu,as well as the thermal quenching performance were studied.It is found that the excitation wavelength range covered the ultraviolet to blue region,and the emission spectrum is a typical broad feature of Eu^(2+)transition.At 300℃,the emitted light intensity of the sample can still reach about 40%that of the room temperature,while the thermal activation energy(Ea)reaches 3.7 eV.Compared with the commercial YAG:Ce^(3+)(YAG)phosphor,the thermal stability of Si_(5)AlON_(7):Eu is improved.The wLED with high color rendering of Ra=87 is realized after compounding with the blue chip,and the corresponding color temperature reaches the warm white light range(CCT=4501 K).In this study,SiAlON-based cyan emission is realized,and the phosphor with excellent thermal stability is obtained.Compared with commercial YAG,it also has obvious advantages in the sustainability of luminescence.