外场辅助高效Mn(IV)掺杂红色荧光粉靶向可控合成、生长机理及作用机制研究

Research focus on white light-emitting diodes (W-LEDs) has changed from their high luminescence efficiency to high color rendering. An efficient red phosphor is essential for the development of W-LEDs with the warm perception similar to incandescent light. As a transition non-rare-earth metal ion, Mn4+ ion has been widely used as an activator for red phosphors due to its spectroscopic properties and economic feasibility. Therefore, it is of academic interesting and potential application to achieve controlled synthesis of Phosphors doped with Mn(IV) for W-LEDs. The aim of this project is to synthesize phosphors doped with Mn(IV) and the crystallization and particle morphology of phosphors is controlled. At the same time, the growth mechanism of the particle is discussed, and interactive mechanism between morphology, structure and properties of phosphors is investigated by first- principles study. These will provide quantitative data and theoretical basis for interactive mechanism between morphology, structure and properties of phosphors, and it is a new thought to control phosphors’ synthesis using modeling method. These will raise technological added value of Guangxi manganese and aluminum resources.

新一代节能光源白光LED的研究热点已从“高亮度”转换为为兼顾显色性能、色温等性能参数“高品质”。红色荧光粉的红色还原性是决定LED光源品质的关键因素。相对稀土离子掺杂荧光粉，Mn(IV)掺杂荧光粉具有蓝光区的宽带激发和相对应的深红发射的特点，外加其原料易得、价格低廉、合成条件温和，非稀土Mn(IV)掺杂的红色荧光粉可控合成研究成为一项有意义的研究课题。本项目以制备尺寸和形貌可控的Mn(IV)掺杂氧化物荧光粉为目标，研究其生长机理，结合外加磁场对其性能影响，建立高性能荧光粉可控合成方法。同时通过构筑结构模型，应用第一性原理计算方法，揭示荧光粉结构、形貌、外加磁场与荧光性能之间的作用机制。该项目的研究结果不仅为揭示荧光粉形貌、外加磁场与荧光性能之间的内在作用机制提供理论依据，还为建模方式应用于靶向荧光粉可控合成提供新思路，同时增加广西特色锰、铝资源的科技附加值。

高性能红光荧光粉的靶向可控合成并建立其荧光性能与微观结构之间的作用机制是一项具有挑战性的研究课题。本项目构建了一系列具有良好发光的红色荧光粉，通过改变合成方法和控制合成条件，实现了荧光粉的形貌可控。通过控制掺杂离子，建立了通过原位掺杂调整样品荧光强度的方法。通过对锰掺杂铝酸盐基质荧光粉的深入研究，证实锰的配位环境是决定荧光粉性能的关键因素，共掺杂离子和共生相的引入是调整配位环境的有效手段。项目组以碱金属离子为共掺离子，控制钠源的用量，结合煅烧温度，实现了MgAl2O4基质中锰价态的可调控。共生相的引入，提高了MgAl2O4/CaAl12O19:Mn4+荧光粉的性能；相对于CaAl12O19:Mn4+荧光粉，MgAl2O4/CaAl12O19:Mn4+的发光强度和内量子效率分别是前者的2.5和2.7倍；通过DFT计算，从形成能角度解释了上述现象。通过本项目，揭示了调整荧光粉微观结构是提高荧光性能的本质，为设计高效荧光粉提供了有效的依据。