Phase stabilization of red-emitting olivine-type NaMgPO4:Eu2+ phosphors via molten-phase quenching
Phase stabilization of red-emitting olivine-type NaMgPO4:Eu2+ phosphors via molten-phase quenching
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DOI：
10.1039/d0qi00880j
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发表时间：
2020-10
影响因子：
7
通讯作者：
T. Hasegawa;Masato Iwaki;R. Tanaka;Sun-Woog Kim;S. Yin;K. Toda
中科院分区：
文献类型：
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作者：
T. Hasegawa;Masato Iwaki;R. Tanaka;Sun-Woog Kim;S. Yin;K. Toda
橄榄石型Eu 2+激活的NaMgPO 4（NMP：Eu 2+）材料以前被发现是一种新的红色发光氧化物荧光体，在蓝光激发下具有高量子效率;然而，使用特殊的和非通用的光学系统的电弧成像炉是必要的。为了实现NMP：Eu 2+的常规管式炉合成，本文采用了一种新的高温快速淬冷合成策略，模拟了电弧成像炉的合成过程。结果，我们成功地稳定了NMP：Eu 2+磷光体中的橄榄石结构。热重-差热分析（TG-DTA）结果表明，NaMgPO 4：0.025Eu2+体系中存在钾芒硝（低温相）和橄榄石（高温相）的多晶型，橄榄石相的稳定区在1000 °C左右，表明快速淬火过程有效地起到了橄榄石相稳定剂的作用。通过X射线衍射（XRD）测试，NMP：Eu 2+荧光粉的主晶相为橄榄石结构。此外，磷光体的光致发光（PL）强度是使用电弧成像炉制备的先前NMP：Eu 2+磷光体的1.3倍。发现NMP：Eu 2+磷光体的内量子效率为72.3%，这是已知的Eu 2+激活的发红光的氧化物磷光体中最高的。此外，其他有关发光二极管（LED）荧光粉的性能，如化学组成，化学状态的Eu，颗粒形态，PL寿命，热猝灭性能，耐湿性和电致发光（EL）性能的制造磷光体转换（pc）-LED，进行了详细的研究。
An olivine-type Eu2+-activated NaMgPO4 (NMP:Eu2+) material was previously discovered as a new red-emitting oxide phosphor with a high quantum efficiency under blue light excitation; however, the use of a special and nonuniversal optical system of an arc-imaging furnace was necessary for its synthesis. To realize the synthesis of NMP:Eu2+ using a conventional tubular furnace, in this work, we employed a new synthetic strategy of rapid quenching from a high temperature, which imitates the synthesis process using the arc-imaging furnace. As a result, we succeeded in stabilizing the olivine structure in the NMP:Eu2+ phosphor. Thermogravimetric-differential thermal analysis (TG-DTA) revealed the presence of the polymorphism of glaserite (low-temperature phase) and olivine (high-temperature phase) phases in the NaMgPO4:0.025Eu2+ composition, and the stabilized region of the olivine phase was found to be around 1000 °C, which indicated that the rapid quenching process effectively acted as an olivine phase stabilizer. According to X-ray diffraction (XRD) measurements, the NMP:Eu2+ phosphor samples have the olivine structure as the main phase. Additionally, the photoluminescence (PL) intensity of the phosphor was 1.3 times that of the previous NMP:Eu2+ phosphor prepared using the arc-imaging furnace. The internal quantum efficiency of the NMP:Eu2+ phosphor was found to be 72.3%, which is the highest among the known Eu2+-activated red-emitting oxide phosphors. Moreover, other properties relevant to light-emitting diode (LED) phosphors, such as the chemical composition, chemical state of Eu, particle morphology, PL lifetime, thermal quenching properties, humidity resistance and electroluminescence (EL) properties of a fabricated phosphor-converted (pc)-LED, were investigated in detail.