紅光螢光粉扮演著仿太陽光LED當中，暖色系的重要角色。然而，紅光的發光中心常是使用對環境有害的稀土元素，例如Eu2+。近年來發現使用Mn4+發光中心可以取代稀土元素，達到發出暖紅光的效果，但是使用Mn4+的母體材料大多受限於氟化物，例如K2TiF6，容易在製程中衍生許多的污染。因此本文的研究方向就是使用Mn4+作為發光中心且使用無氟的母體材料，且提出以第一原理的角度來了解螢光粉與敏化材料之間的關係。基於密度泛函理論，從最基礎的電子結構了解Mg2TiO4: Mn4+螢光粉的各種電子特徵。使用晶體內不同離子距離的結合能，判斷Mg2TiO4逆尖晶石結構的排列，判斷在現實中是隨機排列的16d位置之確定離子分佈，是第一個提出能量最低的Mg2TiO4模型。從能帶變化的角度，可以看出不同參雜濃度的Mn4+對於整體晶格的影響。能態密度可以看出來，Mg2TiO4: Mn4+內各種不同離子佔據的能量大小，再多放入一個元素作為敏化材料，從能態密度的不同重疊方式，選出了”鈮”為最有機會增強Mg2TiO4: Mn4+發光特性的敏化材料。最後，使用固態燒結法合成螢光粉，成功的製備出截至目前發表過，發光強度最強的Mg2TiO4: Mn4+非稀土非氟化物螢光粉，其光致螢光強度達未參雜敏化材料之243%。此研究提出了成功且新穎的方法來了解螢光粉的光學特性，進而設計出理想的產品。

Red light phosphor is the key component for stimulating natural sunlight LEDs. Recent years, Mn4+ luminescence centers are commonly used to substitute environmentally hazardous rare-earth dopants. However, the choice of matrix materials is usually fluoride compound, e.g. K2TiF6, which derivate contaminate issues on silicon industry. In this paper, the ecofriendly “rare-earth-free” and “flouoride-free” red light luminance material, Mg2TiO4 (MTO) with the luminescent center of Mn4+ (MTO:Mn), is investigated. The atomistic models were constructed using ab initio calculations based on density functional theory. The density of states of MTO:Mn with varies potential sensitizers reveal that the best candidate for sensitizer is niobium (Nb). In addition, phosphors were fabricated via solid state sintering. X-ray diffraction spectrum shows no meta-stable phase and photoluminescence spectrum indicates the intensity of light is around 243% after sensitization. This report successfully proposes a novel method to understand optoelectronic properties of phosphors and in turn obtain desirable products. In addition, Mg2TiO4 thin films were as well discussed here. Fabricated by either sol-gel or radio frequency sputtering, annealed at various temperatures and characterized using photoluminescence spectroscopy. Essential physical and optoelectronic properties of the Mg2TiO4 luminance material as well as its optimal processing conditions were comprehensively reported.

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