The Role of Auxiliary Alkali Metal Ions on Scheelite Structure Double Molybdate and Tungstate Phosphors.

Title The Role of Auxiliary Alkali Metal Ions on Scheelite Structure Double Molybdate and Tungstate Phosphors.
Authors J. Kim
Journal Inorg Chem
DOI 10.1021/acs.inorgchem.7b00804
Abstract

Eu3+-doped alkali metal double molybdate and tungstate phosphors, (MEu) (Mo,WO4)2 (MEM and MEW, M = Li+, Na+, and K+), have been identified as potential candidate materials for white light-emitting diodes. However, there are no systematic considerations of the role of auxiliary alkali-metal ions (AMIs) on the structural, chemical, and luminescent properties of these phosphors. Here, a systematic investigation to elucidate the role of AMIs on MEM and MEW phosphors was performed using ab initio calculations based on experimental evidence. The results from experimental assessments with intensive structural and chemical bond analyses reveal a clear dependence of AMIs on the structural and luminescent properties of phosphors. The structural changes due to AMIs originate from a bond length change between AMIs-O2- bonds, and AMIs had minor effects on the other bonds. A phase transition induced by K+ ions originates from not only structural factors but also local chemical bonding characteristics. Overall, the results indicate that the major role of AMIs is to induce phosphor structural changes, and the effects on the chemical properties are minor. The results of this study shed light on developing not only MEM and MEW phosphors but also new phosphor materials using auxiliary metal ions.

Citation J. Kim.The Role of Auxiliary Alkali Metal Ions on Scheelite Structure Double Molybdate and Tungstate Phosphors.. Inorg Chem. 2017;56(14):80788086. doi:10.1021/acs.inorgchem.7b00804

Related Elements

Molybdenum

See more Molybdenum products. Molybdenum (atomic symbol: Mo, atomic number: 42) is a Block D, Group 6, Period 5 element with an atomic weight of 95.96. Molybdenum Bohr ModelThe number of electrons in each of molybdenum's shells is [2, 8, 18, 13, 1] and its electron configuration is [Kr] 4d5 5s1. The molybdenum atom has a radius of 139 pm and a Van der Waals radius of 209 pm. In its elemental form, molybdenum has a gray metallic appearance. Molybdenum was discovered by Carl Wilhelm in 1778 and first isolated by Peter Jacob Hjelm in 1781. Molybdenum is the 54th most abundant element in the earth's crust. Elemental MolybdenumIt has the third highest melting point of any element, exceeded only by tungsten and tantalum. Molybdenum does not occur naturally as a free metal, it is found in various oxidation states in minerals. The primary commercial source of molybdenum is molybdenite, although it is also recovered as a byproduct of copper and tungsten mining. The origin of the name Molybdenum comes from the Greek word molubdos meaning lead.

Tungsten

See more Tungsten products. Tungsten (atomic symbol: W, atomic number: 74) is a Block D, Group 6, Period 6 element with an atomic weight of 183.84. The number of electrons in each of tungsten's shells is [2, 8, 18, 32, 12, 2] and its electron configuration is [Xe] 4f14 5d4 6s2. Tungsten Bohr ModelThe tungsten atom has a radius of 139 pm and a Van der Waals radius of 210 pm. Tungsten was discovered by Torbern Bergman in 1781 and first isolated by Juan José Elhuyar and Fausto Elhuyar in 1783. In its elemental form, tungsten has a grayish white, lustrous appearance. Elemental TungstenTungsten has the highest melting point of all the metallic elements and a density comparable to that or uranium or gold and about 1.7 times that of lead. Tungsten alloys are often used to make filaments and targets of x-ray tubes. It is found in the minerals scheelite (CaWO4) and wolframite [(Fe,Mn)WO4]. In reference to its density, Tungsten gets its name from the Swedish words tung and sten, meaning heavy stone.

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