Highly Regular, Uniform K3ScF6:Mn4+ Phosphors: Facile Synthesis, Microstructures, Photoluminescence Properties, and Application in Light-Emitting Diode Devices
Highly Regular, Uniform K3ScF6:Mn4+ Phosphors: Facile Synthesis, Microstructures, Photoluminescence Properties, and Application in Light-Emitting Diode Devices
复制标题
DOI：
10.1021/acsami.8b01885
复制
发表时间：
2018-06-13
影响因子：
9.5
通讯作者：
Ye, Xinyu
中科院分区：
文献类型：
--
作者：
Ming, Hong;Liu, Shuifu;Ye, Xinyu
新一代Mn ~（4+）激活的复合氟化物红色荧光粉在获得高色质、低色温的固态白色发光二极管（WLED）方面受到广泛关注。然而，除了它们对水分的不稳定性之外，这些磷光体的极不规则和不均匀的形貌限制了它们的实际工业应用。在本研究中，一种新型的K3 ScF 6：Mn 4+红色荧光粉具有高度规则，均匀，高色纯度，成功地通过一个简单的共沉淀路线，在温和的条件下。借助粉末X射线衍射、Rietveld精修和密度泛函理论计算确定了晶体结构。晶体属立方晶系，空间群为Fm 3 m，晶胞参数为a = B = c = 8.4859（8）埃，V= 611.074（2）埃。Mn ~（4+）离子占据Sc ~（3+）晶位，位于畸变的ScF 6八面体的中心。大约6.15eV的宽带隙可以提供足够的空间来容纳杂质能级。与大多数其他Mn 4+离子激活的氟化物磷光体不同，所制备的K3 ScF 6：Mn 4+磷光体表现出高度均匀和规则的形态，随着Mn 4+离子浓度的增加，形状从立方体转变为八面体。在蓝光激发下，K3 ScF 6：Mn 4+样品具有较强的红色荧光（最强峰位于631 nm），色纯度较高。在加热和冷却过程中发光的优异恢复意味着K3 ScF 6：Mn 4+的高稳定性。此外，与K3 ScF 6：Mn 4+和公知的商业YAG：Ce 3+黄色磷光体的混合物合并的蓝色GaN芯片制造的暖WLED表现出良好的颜色质量，具有较低的相关色温（3250 K）和较高的显色指数（R-a = 86.4）。这些结果表明，K_3ScF_6：Mn ~（4+）荧光粉具有巨大的应用潜力。
A new generation of red phosphors of complex fluoride matrices activated with Mn4+ has gained a broad interest in getting high color quality and low color temperature of solid-state white light-emitting diodes (WLEDs). However, besides their instability toward moisture, the extremely irregular and nonuniform morphologies of these phosphors have limited their practical industry applications. In the present study, a novel type of K3ScF6:Mn4+ red phosphor with highly regular, uniform, and high color purity was obtained successfully through a facile coprecipitation route under mild conditions. The crystal structure was identified with aids of the powder X-ray diffraction, Rietveld refinement, and density functional theory calculations. The prototype crystallizes in the space group Fm3m with a cubic structure, and the lattice parameters are fitted well to be a = b = c = 8.4859(8) angstrom and V= 611.074(2) angstrom(3). The Mn4+ ions occupy Sc3+ sites and locate at the centers of the distorted ScF 6 octahedrons. A wide band gap of approximately 6.15 eV can provide sufficient space to accommodate impurity energy levels. Unlike most other Mn4+ ion-activated fluoride phosphors, the as- prepared K3ScF6:Mn4+ phosphors demonstrate highly uniform and regular morphologies with shapes transforming from cube to octahedron with increasing Mn4+ ion concentration. Under blue light excitation, the as-prepared K3ScF6:Mn4+ sample exhibits intense sharp-line red fluorescence (the strongest peak located at 631 nm) with high color purity. An excellent recovery in luminescence upon heating and cooling processes implies high stability of K3ScF6:Mn4+. Furthermore, a warm WLED fabricated with blue GaN chips merged with the mixture of K3ScF6:Mn4+ and the well-known commercial YAG:Ce3+ yellow phosphors exhibits wonderful color quality with lower correlated color temperature (3250 K) and higher color-rendering index (R-a = 86.4). These results suggest that the K3ScF6:Mn4+ phosphor possesses stupendous potentiality for practical applications.