Exploring the optical properties of Vernier phase yttrium oxyfluoride thin films grown by pulsed liquid injection MOCVD

For the first time, thin films of Vernier phase yttrium oxyfluorides, exhibiting efficient luminescence properties, are deposited on Si wafers.

Nanoscopic yttrium oxide fluorides: non-aqueous fluorolytic sol-gel synthesis and structural insights by 19F and 89Y MAS NMR

Nanoscopic yttrium acetate fluorides Y(CH(3)COO)(3-z)F(z) and yttrium oxide fluorides YO(3-z)/(2)F(z )were prepared with tunable Y/F molar ratios via the fluorolytic sol-gel route. All samples were characterized by X-ray diffraction, elemental analysis and thermal analysis. In addition, local structures of all samples were studied by (19)F MAS, (19)F-(89)Y CP MAS and (1)H-(89)Y CP MAS NMR spectroscopy and the respective chemical shifts are given. For both classes of compounds, only the fluorination using one equivalent of F (z = 1) leads to defined, well crystalline matrices: yttrium acetate fluoride Y(CH(3)COO)(2)F and r-YOF.

High thermal sensitivity and the selectable upconversion color of Ln, Yb:Y6O5F8 nanotubes

The high thermal sensitivity of Er, Yb:Y₆O₅F₈ and the selectable upconversion color light achieved with Pr, Er, Yb:Y₆O₅F₈ indicate the suitability of easily prepared crystalline oxyfluoride microstructures in thermal sensing and for display and lighting technologies.

The up-conversion luminescent properties and silver-modified luminescent enhancement of YVO4:Yb3+, Er3+ NPs

In this paper, the unique up-conversion luminescence (UCL) properties of as-prepared and annealing YVO(4):Yb(3+), Er(3+) nanoparticles (NPs, ∼100 nm) and the corresponding YVO(4):Yb(3+), Er(3+)@Ag hybrids under 980 nm excitation were systemically studied through power-dependent, temperature-dependent emission spectra and dynamics. It is interesting to determine that the radiative transition rate of (2)H(11/2)/(4)S(3/2)-(4)I(15/2) for Er(3+) ions in YVO(4) is about an order of magnitude faster than that in the other hosts due to the wave function coupling with the 3d orbital of V(5+) and, thus, the up-conversion (UC) green emissions of YVO(4):Yb(3+), Er(3+) NPs is efficient. In addition, efficient novel UC broad band centering around 630 nm (1.97 eV) was observed in YVO(4):Yb(3+), Er(3+) powders, which was attributed to defect emissions related to oxygen vacancies near V(5+) sites in the lattices of YVO(4). In as-prepared YVO(4):Yb(3+), Er(3+)@Ag hybrids colloids, more than one order UCL enhancement than YVO(4):Yb(3+), Er(3+) was observed. Powder and the annealing samples lead the UCL enhancement effect to disappear. The main UCL enhancement mechanism of YVO(4):Yb(3+), Er(3+)@Ag hybrids colloids was attributed to prevent YVO(4):Yb(3+), Er(3+) interaction with the solution, instead of surface plasmon enhancement (SPE) effect.

Up-conversion luminescence and near-infrared quantum cutting in Y6O5F8:RE3+ (RE = Yb, Er, and Ho) with controllable morphologies by hydrothermal synthesis

Monodisperse and uniform Y(6)O(5)F(8):RE(3+) (RE = Yb, Er, and Ho) microarchitectures with various morphologies have been constructed by a facile surfactant-assisted hydrothermal route, and their up-conversion luminescence and NIR quantum cutting properties were investigated. Hollow hexagonal prisms, microbundle gatherings by rods, and solid hexagonal prisms were designed by employing CTAB, PVP, and EDTA as additives, respectively. Under 980 nm excitation, the Y(5.34)O(5)F(8):0.6Yb(3+), 0.06Er(3+) samples obtained using different additives exhibit similar emission spectra profiles with predominating peaks at 670 nm; the Y(5.34)O(5)F(8):0.6Yb(3+), 0.06Ho(3+) samples give green emissions with the strongest peaks around 544 nm. The NIR quantum cutting for the Y(6)O(5)F(8):Yb(3+), Ho(3+) samples was identified by the NIR emission spectra upon both 360 and 450 nm excitation. The corresponding quantum cutting mechanisms were discussed through the energy level diagrams, in which a back-energy-transfer from Yb(3+) to Ho(3+) was first proposed to interpret the spectral characteristics. A modified calculation equation for the quantum efficiency of Yb(3+)-Ho(3+) coupled by exciting at 450 nm was suggested according to the quantum cutting mechanism. The efficient NIR luminescence and quantum cutting in Yb(3+), Ho(3+) co-doped Y(6)O(5)F(8) reveal a possible application in modifying the solar spectrum to enhance the efficiency of silicon solar cells.