新型近紫外激发单一基质荧光粉Sr2V2O7:Ln(Ln=Eu3+, Dy3+, Sm3+, Tb3+)的研究

    Novel Single Phase Sr2V2O7:Ln (Ln=Eu3+,Dy3+,Sm3+,Tb3+) Phosphors for White LEDs with Near Ultraviolet Excitation

    • 摘要: 为了研制一种具有优越稳定性能、易于合成、吸收和近紫外芯片匹配、发光效率高的LED用新型单一基质的暖白光荧光粉, 采用高温固相反应法在空气氛围下制备了单一基质的Sr2V2O7(SVO):Ln(Ln=Eu3+, Sm3+, Dy3+, Tb3+)系列白光LED荧光粉. 利用X射线衍射(XRD)和荧光光谱分别研究了样品的晶体结构, 发光特性和能量传递机理, 在350 nm的紫外激发下SVO基质自身发射黄绿色的宽光谱. 荧光光谱的研究表明所有掺杂的样品都有一个基质电荷跃迁引起的近紫外激发宽带, 而且SVO基质与稀土离子Eu3+, Dy3+, Sm3+, Tb3+之间都存在着能量传递. 此外, 根据Dexter理论, 基质和4种稀土离子之间的能量传递机理都是电偶极−偶极相互作用. 研究结果表明, 通过稀土掺杂可以增强荧光强度、调控发光颜色、改善色温、提高显色指数, SVO:Ln(Ln=Eu3+, Dy3+, Sm3+, Tb3+)是适合近紫外芯片激发的单一基质白光荧光粉.

       

      Abstract: In order to develop novel single phase phosphors for warm white LEDs with superior stability, easy synthesis, strong absorption in near ultraviolet matching blue chip and high luminescence efficiency, novel single phase Sr2V2O7(SVO):Ln(Ln=Eu3+, Dy3+, Sm3+, Tb3+) phosphors for white LEDs were prepared by the high-temperature solid-state reaction method under air atmosphere. The crystal structures, photoluminescence (PL) properties and energy transfer between the host and rare earth ions were investigated by X-ray diffraction (XRD) patterns and luminescence spectra. SVO phosphor is a novel phosphor for near ultraviolet white LEDs, emitting intense and broad yellow-greenish light upon the 350 nm excitation. It is concluded from the photoluminescence spectra that all samples doped with rare earth ion exhibited a broad near ultraviolet band due to charge transfer transition of the SVO host, indicating that there were energy transfers from the host SVO to Eu3+, Dy3+, Sm3+, Tb3+ ions, respectively. Furthermore, the energy transfers from VO43− to rare earth ions occurred mainly via dipole-dipole interactions according to Dexter’s theory. The results shows that through doping rare-earth ions into SVO host, the luminescent intensity was enhanced, the CIE coordinates were adjusted and the correlated color temperature were reduced, demonstrating that phosphors SVO:Ln (Ln=Eu3+, Dy3+, Sm3+, Tb3+) phosphors are promising single phase converting phosphors for white LEDs with near UV chips.

       

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