Synthesis and Luminescence Improvement of CaAlSiN_(3)Phosphors Doped with Eu^(2+)and Mn^(2+)for White LEDs

白光LEDs用掺杂Eu^(2+)和Mn^(2+)的CaAlSiN_(3)荧光粉合成及发光性能改进

Eu^(2+)and Mn^(2+)co-activated CaAlSiN_(3)red phosphors were produced using the solid-state reaction tech⁃nique in a N2 environment.Excitation spectra,emission spectra,and diffuse reflection spectra were used to study the luminescence characteristics,energy gap,and thermal stability in detail.CaAlSiN_(3)∶Eu^(2+)exhibits an extended emission band when stimulated with 450 nm blue light,which is caused by the 4f65d to 4f7 transition of Eu^(2+).Similar⁃ly,CaAlSiN_(3)∶Mn^(2+)displays a wide emission band centered at 628 nm,which results from Mn^(2+)’s transition from 4T1(4G)to 6A1(6S).When the ions of Mn^(2+)were combined into CaAlSiN_(3)∶Eu^(2+),the photoluminescence intensity of Eu^(2+)was greatly boosted because there was energy transfer and co-emission between Mn^(2+)and Eu^(2+).Beyond that,CaAlSiN_(3)∶Eu^(2+),Mn^(2+)emerges with splendid thermostability and high quantum efficiency,the quenching temperature surpasses 300℃,and the internal quantum efficiency is determined to be around 84.9%.The white LED was pack⁃aged with a combination of CaAlSiN_(3)∶Eu^(2+),Mn^(2+),LuAG∶Ce3+and a blue chip.At a warm white-light corresponding color temperature(3009 K)with CIE coordinates(0.4223,0.3748),the color rendering index Ra has reached 93.2.CaAlSiN_(3)∶Eu^(2+),Mn^(2+)would have great application potential as a red-emitting phosphor for white LEDs.

采用固相反应法在N2环境下制备了Eu^(2+)和Mn^(2+)共激活的CaAlSiN_(3)红色荧光粉。利用激发光谱、发射光谱和漫反射光谱对其发光特性、能带以及热稳定性进行了详细的研究。在450 nm蓝光激发下,CaAlSiN_(3)∶Eu^(2+)呈现出较宽的发射带,这是由Eu^(2+)的4f65d到4f7跃迁引起的。类似地,CaAlSiN_(3)∶Mn^(2+)呈现出以628 nm为中心的宽发射带,这源于Mn^(2+)从4T1(4G)到6A1(6S)跃迁的结果。当Mn^(2+)掺杂到CaAlSiN_(3)∶Eu^(2+)时,由于Mn^(2+)与Eu^(2+)之间存在能量传递和共发射,使得Eu^(2+)的光致发光强度获得较大的提升。此外,CaAlSiN_(3)∶Eu^(2+),Mn^(2+)表现出良好的热稳定性和高量子效率,猝灭温度超过300℃,内量子效率约为84.9%。采用CaAlSiN_(3)∶Eu^(2+),Mn^(2+)、LuAG∶Ce3+和蓝光芯片的组合封装成白光LED,暖白光下对应的色温为3009 K,CIE坐标为(0.4223,0.3748),显色指数Ra达到93.2。CaAlSiN_(3)∶Eu^(2+),Mn^(2+)作为用于白光LED的红光荧光粉具有很大的应用潜力。