Yongzheng Fang

Comparative study of 27 μm emission of Ho^3+ desensitized Er^3+ in tellurite and bismuth glass

Energy transfer mechanisms have been quantitatively studied in Er3+/Ho3+ codoped tellurite and bismuth glass. Upon an excitation of 980 nm, an enhanced Er3+:2.7 μm emission was observed when Ho3+ was added to tellurite glass. Using Dexter’s theory, it is clearly shown that the efficiency of Er3+:4I13/2 → Ho3+:5I7 energy transfer is higher in tellurite glass than in bismuth glass. Based on upconversion and near-infrared spectra, the cross relaxation Er3+:4I13/2 + Ho3+:5I6 → Er3+:4I15/2 + Ho3+:5F5 is comparatively effective in tellurite glass, where it depletes the population of Er3+:4I13/2 level. The excellent spectroscopic characteristics indicate Er3+/Ho3+ co-doped tellurite glass has potential application for mid-infrared laser.

Asterisk-shaped microstructured fiber for an octave coherent supercontinuum in a sub-picosecond region

We selected two thermally matched silicate glasses with fair refractive index contrast and developed an asterisk-shaped all-solid microstructured optical fiber. The fiber presents a low, ultra-flat, and all-normal dispersion in a wide wavelength range, allowing for the generation of an octave-spanning coherent supercontinuum (SC) in a 20xa0dB dynamic range with 0.5xa0ps pump pulses at 1.55xa0μm. This result improves pump pulse duration that is only ∼100u2009u2009fs, related to the broadband and highly coherent SC generation in fibers with all-normal dispersion. This enables broadband SC sources with all-fiber, high-power, and highly coherent properties.

Influence of the synthesis atmosphere on NIR fluorescence behavior of Ce/Er co-doped bismuth glass through valence state changes of cerium

This work investigates the near-infrared emission characteristics and energy transfer between erbium and cerium in bismuth glass by the reaction atmosphere process. The Er3+:1.5μm emission can be successfully enhanced by performing a reduction conversion of Ce4+→Ce3+ using a reducing atmosphere. The discrepancies of the energy structure between Ce3+ and Ce4+ result in a contrasting sensitizing effect on Er3+:1.5μm emission intensity and decay lifetime. The results show that a significant amount of Ce3+ is present in glasses prepared in a reducing atmosphere, whereas Ce4+ is the main species in an oxidizing atmosphere by means of absorption spectra and XPS curves. The reason for upconversion quenching is also discussed.

White-light-emitting from single-phased (Ca,Eu,Mn)9Al(PO4)7 phosphor with blue-white-yellow tunable luminescence properties for UV-based LEDs

ABSTRACT Single-phased white light emitting (Ca,Eu,Mn)9Al(PO4)7 phosphors were synthesized by conventional one-step reduction solid state reaction. The emission colors could be tuned from blue (0.170, 0.082) to white light (0.299, 0.316) and eventually to yellow (0.390, 0.400) through an efface energy transfer by controlling the dopant Eu2+/Mn2+ concentration. Energy transfer between the sensitizer Eu2+ and the activator Mn2+ has been studied and demonstrated to be a resonant type via a dipole-dipole interaction mechanism. Emissions from Eu2+ and Mn2+ in Ca9Al(PO4)7 exhibits excellent thermal stability and synchronicity. Finally, a white-LED with Ra = 79 was fabricated by using a 380 nm UV chip with single-phased (Ca0.965Eu0.005Mn0.03)Al(PO4)7 phosphor.

White light emission from Eu3+ singly activated Ca8(Al12O24)(MoO4)2 with host-sensitized properties for solid state light source application

We report a Eu3+ ions singly doped Ca8(Al12O24)(MoO4)2 (CAM:Eu3+) single-phased white light emitting phosphors prepared by conventional solid-state reaction. Upon excitation of 280xa0nm light, the CAM:Eu3+ presented a broad emission band ranging from ~u2009350 to 600xa0nm and sharp lines in red region, which originating from the M–O group and 5D0 → 7FJ (Ju2009=u20090, 1, 2, 3, 4) transitions of Eu3+ ions, respectively. Energy transfer from the Mo–O group to Eu3+ ions occurred in this unique host was discussed. Through an effective synergistic contribution of

Synthesis of Fe2P coated LiFePO4 nanorods with enhanced Li-storage performance

left[ {{text{MoO}}_{4}^{{2 - }}} right]

A non-vacuum solution route to prepare amorphous metal oxides thin films for Cu2ZnSn(S,Se)4 solar cells

MoO42- and Eu3+ ions, white light emission was finally achieved.

A visible-light driven Bi2S3@ZIF-8 core–shell heterostructure and synergistic photocatalysis mechanism

A series of single-phased Ca11(SiO4)4(BO3)2:Ce3+, Tb3+, Mn2+ phosphors were prepared by conventional one-step reduction solid state reaction, and their luminescent properties were investigated. Red, green and blue light emission from Mn2+, Tb3+ and Ce3+ were well balanced in Ca11(SiO4)4(BO3)2 (abbreviated as CSB), and a white light emission was obtained with chromatic coordinate of (0.303, 0.309) under a 338xa0nm UV light excitation. Energy transfer processes from Ce3+ to Tb3+ and Ce3+ to Mn2+ in CSB were investigated and discussed. Finally, a white light emitting diode with high color rending index of Rau2009=u200992.2 was fabricated by using a 365xa0nm UV chip with the optimized (Ca0.91Ce0.01Mn0.05Tb0.03)11(SiO4)4(BO3)2 phosphor.