Red-emitting K3HF2WO2F4:Mn4+ for application in warm-white phosphor-converted LEDs: optical properties and magnetic resonance characterization.
JANSEN, Thomas; FUNKE, Lena Marie; GOROBEZ, Jürgen; BÖHNISCH, David; HOFFMANN, Rolf-Dieter; HELETTA, Lukas; PÖTTGEN, Rainer; HANSEN, Michael Ryan; FICKENSCHER, Thomas; JÜSTEL, Thomas; ECKERT, Hellmut.
JANSEN, Thomas; FUNKE, Lena Marie; GOROBEZ, Jürgen; BÖHNISCH, David; HOFFMANN, Rolf-Dieter; HELETTA, Lukas; PÖTTGEN, Rainer; HANSEN, Michael Ryan; FICKENSCHER, Thomas; JÜSTEL, Thomas; ECKERT, Hellmut.
 Abstract: We report novel efficient Mn4+ phosphors of composition K3HF2MO2F4:Mn4+ (M = Mo, W) containing [HF2]- and octahedral [MO2F4]2- building units. The phosphor exhibits strong absorption at 450 nm and an external quantum yield of 90%. K3HF2WO2F4:0.01Mn4+ provides a sufficiently high quenching temperature T1/2 of about 400 K and is applicable as a converter for (In,Ga)N LEDs. The EPR spectrum is consistent with the presence of a MnF6 2- species at giso = 1.983. 19F MAS NMR results confirm the 2 : 1 ratio of the metal-bound fluoride species to the hydrogen difluoride group as predicted from the chemical formula. There are two distinct M-bonded species in a 1 : 1 ratio, indicating that the W and Mo octahedra are exclusively of the MO2F4 2- type, with the two oxygen atoms in cis-position. Their extremely sharp 19F resonances indicate a fast, near-isotropic reorientational process at room temperature that is on the millisecond timescale. For the HF2 - group, the 19F and 1H MAS NMR spinning sideband profiles reveal the geometry of a linear centrosymmetric three-spin system with an H-F bond distance of 1.14 Å. | |
| Dalton Transactions |
| v. 48, n. 16, p. 5361-5371 - Ano: 2019 |
| Fator de Impacto: 4,099 |
| http://dx.doi.org/10.1039/c9dt00091g |  @article={002939083,author = {JANSEN, Thomas; FUNKE, Lena Marie; GOROBEZ, Jürgen; BÖHNISCH, David; HOFFMANN, Rolf-Dieter; HELETTA, Lukas; PÖTTGEN, Rainer; HANSEN, Michael Ryan; FICKENSCHER, Thomas; JÜSTEL, Thomas; ECKERT, Hellmut.},title={Red-emitting K3HF2WO2F4:Mn4+ for application in warm-white phosphor-converted LEDs: optical properties and magnetic resonance characterization},journal={Dalton Transactions},note={v. 48, n. 16, p. 5361-5371},year={2019}} |
