Abstract Monoclinic double perovskite La2LiMO6:Eu3+(M = Sb, Ta, Nb) phosphors were prepared by high temperature solid state reaction method in air. The material microstructures were characterized by XRD Rietveld refinement. All La2LiMO6:Eu3+ exhibited Eu3+ - emission in the red region under excitation by ultraviolet-blue light at room temperature. In the order of M = Sb, Ta, Nb, the emission of Eu3+ in La2LiMO6:Eu phosphor declined under charge transition band (CTB) excitation in turn, while enhanced gradually under 394 nm and 465 nm excitation. The optical band gap energy was calculated through the UV–Vis reflectance spectra of La2LiMO6:Eu indicating that photoionization is the quenching scheme in La2LiMO6:Eu. Co - doped with Bi3+ ions further reduces the energy band (i.e. forbidden bandwidth) of LLN:Eu, resulting in the significant enhancement of Eu3+- emission under 465 nm excitation, which demonstrates its potential application value as the red component of a blue chip based-white LED.

中文翻译：

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能带结构对双钙钛矿 La2LiMO6:Eu3+ (M=Sb, Ta, Nb) 红色荧光粉发光性能的影响

摘要 采用空气中高温固相反应法制备了单斜双钙钛矿La2LiMO6:Eu3+(M = Sb, Ta, Nb)荧光粉。材料微观结构通过XRD Rietveld精修表征。所有 La2LiMO6:Eu3+ 在室温下紫外-蓝光激发下都在红色区域显示 Eu3+ - 发射。按照M = Sb、Ta、Nb的顺序，La2LiMO6:Eu荧光粉中Eu3+的发射在电荷过渡带（CTB）激发下依次下降，而在394 nm和465 nm激发下逐渐增强。通过 La2LiMO6:Eu 的 UV-Vis 反射光谱计算光学带隙能量，表明光电离是 La2LiMO6:Eu 中的猝灭方案。Co - 掺杂 Bi3+ 离子进一步降低了 LLN:Eu 的能带（即禁带带宽），