暖白光LED用单分散K2TiF6:Mn4+发光材料的制备、光学特性与性能研究

Octahedron K2TiF6:Mn4+ phosphor exhibits excellent broadband blue excitation and narrowband red light emission characteristics. Its excitation band is perfectly accordance with the emissions of white light-emitting diode (WLED) chip, and its emissions can supply the missing red component of cold WLEDs. However, its research mainly focused on the preparation, optical properties and performance of large particulate and irregular phosphor powders. Monodispersed luminescent materials can present enhanced optical properties, such as emission intensity, efficiency and improved LED optical performance stability than those of traditional luminescent materials. Therefore, preparing monodispersed luminescent materials, adjusting its size, controlling its morphology, studying its luminescence mechanism and exploring its optical performance are important research area for this type of materials. This program propose to construct novel monodispersed fluoride K2TiF6:Mn4+ red luminescent phosphors and mainly contains: (1) design and synthesize monodispersed K2TiF6 host materials, adjusting its size, controlling its morphology and investigating its growth mechanism; (2) construct monodispersed K2TiF6:Mn4+ luminescent materials with different size and morphology, investigating it energy transfer principle, exploring the relationships among its size, morphology, properties and optical performance.

八面体构型的K2TiF6:Mn4+ 发光材料具有优异的宽蓝光激发、窄红光发射特性，其激发带完美匹配于白光二极管芯片的发射，发射可补充白光LED所缺少的红光成分，但研究多集中于大颗粒、无规则发光粉体的制备、发光特性和性能研究上。单分散发光材料可对材料光学性质，如发光强度、效率，和LED光学性能的稳定性进行改进和增强，因此，将K2TiF6:Mn4+发光材料均一化、规则化，调节其尺寸、控制其形貌，研究其发光机制，探索其发光性能将是此类发光粉的重要研究方向。本项目以单分散K2TiF6:Mn4+红色发光材料的构建为主要研究内容：（1）设计、合成新型单分散K2TiF6基质材料，调节材料尺寸，控制材料形状，研究材料生长机理；（2）构筑多种尺寸均一、形貌一致的单分散K2TiF6:Mn4+发光粉，研究其能量传递机制，发掘其尺寸、形貌与性质、性能之间的关系。

针对暖色调白光LED用红光材料研究的不足，以过渡金属离子Mn4+为核心，在液相环境下合成了一系列结构新颖、发光强度和峰位可控的氟化物红光材料，开展了这类材料的光学性质如发光强度、峰位、效率、寿命和LED性能研究，对其能量传递机制，形貌、结构与光学性质、发光性能之间的关系进行了系统的研究。在四个方面取得了较好的研究成果：（一）从Mn2+和Mn4+在固相材料中的光学性质出发，总结了单掺Mn2+、共掺Ce3+与Mn2+、共掺Eu2+与Mn2+白光材料及Mn4+激活的氟化物与氧化物红光材料在固相合成、湿化学合成与白光LED应用方面的研究进展；（二）以获取形态规则、大小均一的掺Mn4+氟化物红光材料为出发点，利用水热法合成了均匀的六棱柱红光材料，研究了规则的发光粉体与不规则粉体在发光亮度与强度上的区别；（三）利用中心离子与Mn4+电荷一致、半径类似的特点，以氟化物Rb2NaAlF6、Rb2KGaF6、A2HfF6和氧氟化物BaTiOF4为基质，开发了若干具有优良热稳定、发光性能强的掺Mn4+氟化物和氧氟化物红粉；另外，以无污染的冰醋酸为溶液，合成了A2TiF6:Mn4+化合物，研究了冰醋酸用量与产物光学性质与发光性能之间的关系；（四）基于调控Mn4+光谱的设想，开展了增强其红光发射与调控其主发射峰位置/强度的研究工作，开发了若干具有优良热稳定、高色纯度和发光性能的氟化物红光材料。