Na_(1-x)M_(x)CaEu(WO_(4))_(3)(M=Li,K)红色荧光粉的微观结构与热淬灭特性研究  

Microstructure and Thermal Quenching Characteristics of Na_(1-x)M_(x) CaEu(WO_(4))_(3)(M=Li,K) Red Phosphor

作　　者：关旭峰 李桂芳 卫云鸽 GUAN Xufeng;LI Guifang;WEI Yunge(School of Advanced Materials and Nano Technology,Xidian University,Xi'an 710071,China)

机构地区：[1]西安电子科技大学先进材料与纳米科技学院,西安710071

出　　处：《无机材料学报》2022年第6期676-682,共7页Journal of Inorganic Materials

基　　金：国家自然科学基金(61974114)。

摘　　要：红色荧光粉对改善白光LED(w-LEDs)发光性能具有至关重要的作用。为制备与商用LED芯片相符的、高效和稳定性好的红色荧光粉,本研究采用传统高温固相法合成了系列四方白钨矿结构的Na_(1-x)M_(x)CaEu(WO_(4))_(3)(M=Li,K)红色荧光粉,并系统研究了Li^(+)和K^(+)的掺杂对NaCaEu(WO_(4))_(3)荧光粉晶体结构、发光性能以及热淬灭特性的影响。Rietveld精修结果显示,掺杂Li^(+)和K^(+)没有改变NaCaEu(WO_(4))_(3)基质的四方白钨矿结构,而是形成了固溶体,并且导致晶格常数呈现规律性的变化。光致发光光谱表明,在近紫外光395 nm激发下,荧光粉呈现典型的红色发射,其最强发射峰位于617 nm处,对应于Eu^(3+)离子的5 D_(0)→7 F_(2)跃迁,这表明Eu^(3+)处于非对称中心格位。更值得注意的是掺杂Li^(+)和K^(+)有效改善了NaCaEu(WO_(4))_(3)荧光粉的发光强度,当Li^(+)和K^(+)的掺杂浓度(物质的量分数)分别为100%和30%时,荧光粉的发光强度和色纯度达到最佳。此外,还对Na_(1-x)M_(x)CaEu(WO_(4))_(3)(M=Li,K)荧光粉的热淬灭特性机理进行了研究。结果显示,掺杂Li^(+)和K^(+)荧光粉均表现出卓越的热淬灭特性,其中当Li^(+)掺杂浓度(物质的量)为100%时,LiCaEu(WO_(4))_(3)荧光粉的热淬灭特性最佳。以上研究结果均表明Na_(1-x)M_(x)CaEu(WO_(4))_(3)(M=Li,K)红色荧光粉在大功率近紫外激发的白光发光二极管中具有潜在的应用价值。Red phosphors play a vital role in improving the photoluminescence properties of white LEDs(w-LEDs).In order to prepare high efficiency and stability red phosphor for commercial LED chips,a series of tetragonal scheelite structure Na_(1-x)M_(x)CaEu(WO_(4))_(3)(M=Li,K)red phosphors were synthesized by a solid state reaction method.The effect of Li^(+)and K^(+)doping on the crystal structure,photoluminescence properties and thermal quenching characteristics of NaCaEu(WO_(4))_(3) phosphor were investigated systematically.Rietveld refinement results show that the doping of Li^(+)and K^(+)exerts change on the tetragonal scheelite structure of the NaCaEu(WO_(4))_(3) host,but forms the solid solution,and results in the regular change in the lattice constant.The photoluminescence spectra show that under the excitation of near ultraviolet light at 395 nm,the phosphors exhibit a typical red emission,with the strongest emission peak at 617 nm,corresponding to the 5 D_(0)→7 F_(2) transition of Eu^(3+)ion,which indicates that Eu^(3+)is situated in non-central symmetric lattices in NaCaEu(WO_(4))_(3) host.It is noteworthy that the doping of Li^(+)and K^(+)effectively improves the emission intensity of the NaCaEu(WO_(4))_(3) phosphor.When the doping concentration(molar percent)of Li^(+)and K^(+)is 100%and 30%,respectively,both the emission intensity and the color purity realize optimum.In addition,thermal stability and thermal quenching characteristics of Na_(1-x)M_(x)CaEu(WO_(4))_(3)(M=Li,K)phosphors were studied.The results show that both Li^(+)and K^(+)doped phosphors display excellent thermal quenching,and when the Li^(+)doping concentration(molar percent)is 100%,LiCaEu(WO_(4))_(3) phosphor processes the best thermal quenching.All results demonstrate that Na_(1-x)M_(x)CaEu(WO_(4))_(3)(M=Li,K)red phosphors can be applied to high-power NUV(Near ultraviolet)excited white light emitting diodes potentially.

关 键 词：荧光粉 白钨矿结构 热淬灭特性 光致发光特性 

分 类 号：TQ174[化学工程—陶瓷工业]