Hasegawa Takuya, Abe Yusuke, Koizumi Atsuya, Ueda Tadaharu, Toda Kenji, Sato Mineo
Department of Marine Resources Science, Faculty of Agriculture and Marine Science, Kochi University , Nankoku 783-8502, Japan.
Center for Advanced Marine Core Research, Kochi University , Nankoku 783-8502, Japan.
Inorg Chem. 2018 Jan 16;57(2):857-866. doi: 10.1021/acs.inorgchem.7b02820. Epub 2017 Dec 28.
Extensive attention has been focused toward studies on inexpensive and rare-earth-free garnet-structure vanadate phosphors, which do not have a low optical absorption due to the luminescence color being easily controlled by its high composition flexibility. However, bluish emission phosphors with a high quantum efficiency have not been found until now. In this study, we successfully discovered bluish-white emitting, garnet structure-based LiCaMVO (M = Zn and Mg) phosphors with a high quantum efficiency, and the detailed crystal structure was refined by the Rietveld analysis technique. These phosphors exhibit a broad-band emission spectra peak at 481 nm under near UV-light excitation at 341 nm, indicating no clear difference in the emission and excitation spectra. A very compact tetrahedral [VO] unit is observed in the LiCaMVO (M = Zn and Mg) phosphors, which is not seen in other conventional garnet compounds, and generates a bluish-white emission. In addition, these phosphors exhibit high quantum efficiencies of 40.1% (M = Zn) and 44.0% (M = Mg), respectively. Therefore, these vanadate garnet phosphors can provide a new blue color source for LED devices.
大量的注意力集中在对廉价且无稀土的石榴石结构钒酸盐荧光粉的研究上，由于其高成分灵活性使得发光颜色易于控制，所以这类荧光粉不存在低光吸收的问题。然而，迄今为止尚未发现具有高量子效率的蓝色发射荧光粉。在本研究中，我们成功发现了基于石榴石结构的具有高量子效率的蓝白色发光的LiCaMVO（M = Zn和Mg）荧光粉，并通过Rietveld分析技术对其详细晶体结构进行了精修。这些荧光粉在341 nm的近紫外光激发下，在481 nm处呈现宽带发射光谱峰，表明发射光谱和激发光谱没有明显差异。在LiCaMVO（M = Zn和Mg）荧光粉中观察到一个非常紧凑的四面体[VO]单元，这在其他传统石榴石化合物中未见，并且产生蓝白色发射。此外，这些荧光粉分别表现出40.1%（M = Zn）和44.0%（M = Mg）的高量子效率。因此，这些钒酸石榴石荧光粉可为LED器件提供一种新的蓝色光源。
