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Novel broadband luminescence phosphors Ca2−xNaMg2V3O12:xEu3+ have been successfully prepared via the conventional high-temperature solid-state reaction. The effects of concentrations of doped Eu3+ and introducing Li+, K+ on the luminescent properties of phosphor were studied. X-ray diffraction, GSAS structural refinement and photoluminescence spectra were used to characterize the samples. The refinement data ensured where the doped Eu3+ ions occupied the lattice site in the host. Under 355 nm excitation, the emission peak of Ca2NaMg2V3O12:Eu3+ phosphors are located at 610 nm (red) ascribed to the electric dipole transition of Eu3+ from 5D0 → 7F2. In the range of 400–575 nm, Ca2NaMg2V3O12:Eu3+ phosphors have broad emission bands attributed to charge transfer of $${\text{VO}}_4^{3 - }$$ group. Energy transfer mechanism, energy transfer efficiency and critical distance (Rc) of $${\text{VO}}_4^{3 - }$$ → Eu3+ would be analyzed. The emitting color of Ca2NaMg2V3O12:Eu3+ could be tunable from blue-green to near white light.

A novel series of color-tunable single-phased phosphors La1–x–yPO4:xEu3+/yTb3+(x=0, 0.01, 0.02, 0.03, 0.04, 0.05; y=0, 0.05, 0.10, 0.15, 0.20) was synthesized via co-precipitation method with diammonium hydrogen phosphate as precipitant. The morphology, crystal structure and photoluminescence properties of the as-prepared samples were characterized by means of X-ray diffraction(XRD), scanning electron microscopy(SEM) and fluorescence spectrophotometer. The results reveal that the as-synthesized samples calcined at 1100 °C display spherical morphology with uniform distribution. Upon excitation with 350 nm ultraviolet radiation, the LaPO4:Eu3+/Tb3+ phosphors showed a green light peaking at 543 nm assigned to the characteristic 5D4-7F5 emission of Tb3+ and a red light peaking at 591 nm corresponding to the characteristic 5D0-7F1 emission of Eu3+ simultaneously. For the Eu3+/Tb3+ co-activated phosphors, Tb3+ acts as an efficient sensitizer to enhance the emission intensity of Eu3+ ions. The energy transfer mechanism and the emission color tunability of LaPO4:Eu3+/Tb3+ have been studied. The results indicate that a color-tunable luminescence(from green to white to red) can be achieved by adjusting the Eu3+/Tb3+ doping ratio in the LaPO4 host matrix.

Cu2+ doped CeO2 porous nanomaterials were synthesized by calcining CeCu–MOF nanocrystals. They exhibited a superior bifunctional catalytic performance for CO oxidation and selective catalytic reduction of NO., Copper doped ceria porous nanostructures with a tunable BET surface area were prepared using an efficient and general metal–organic-framework-driven, self-template route. The XRD, SEM and TEM results indicate that Cu2+ was successfully substituted into the CeO2 lattice and well dispersed in the CeO2:Cu2+ nanocrystals. The CeO2:Cu2+ nanocrystals exhibit a superior bifunctional catalytic performance for CO oxidation and selective catalytic reduction of NO. Interestingly, CO oxidation reactivity over the CeO2:Cu2+ nanocrystals was found to be dependent on the Cu2+ dopants and BET surface area. By tuning the content of Cu2+ and BET surface area through choosing different organic ligands, the 100% conversion temperature of CO over CeO2:Cu2+ nanocrystals obtained from thermolysis of CeCu–BPDC nanocrystals can be decreased to 110 °C. The porous nanomaterials show a high CO conversion rate without any loss in activity even after five cycles. Furthermore, the activity of the catalysts for NO reduction increased with the increase of BET surface, which is in accordance with the results of CO oxidation.

Nanosized Ce 3+ and Tb 3+ co-doped LaPO 4 phosphors were synthesized by a mixed co-precipitation method using oxalic acid (H 2 C 2 O 4 ·2H 2 O) and ammonium dibasic phosphate ((NH 4 ) 2 HPO 4 ) as the precipitants. The morphology, crystal structure and photoluminescence properties of the synthesized LaPO 4 :Ce 3+ ,Tb 3+ phosphors were investigated by thermo-gravimetry and differential scanning colorimetry, X-ray diffraction, scanning electron microscope, and photoluminescence emission spectra methods. The results showed that the pure phase of lanthanum orthophosphate can be formed with a lower calcining temperature compared to that of the traditional solid-state reaction method. LaPO 4 phosphors doped with 20 mol% Tb 3+ and 40 mol% Ce 3+ , which were calcined at 900 °C for 1 h, reached the maximum emission intensity under 265 nm excitation. The most prominent emission was at 543 nm, which corresponded to the 5 D 4 → 7 F 5 transition of Tb 3+ ions.

Trivalent neodymium ion doped yttria (Nd 3+ :Y 2 O 3 ) nanopowders were synthesized by using a glycine combustion method. The characteristics of the Nd 3+ :Y 2 O 3 nanopowders with different calcination temperatures and Nd 3+ ion doping concentrations were analyzed to determine the optimum synthesis conditions of the samples. Thermo-gravimetry and differential scanning colorimetry (TG/DSC), XRD and FTIR analysis showed that the novel glycine-gel microwave combustion method can provide an effective reaction to form yttria nanopowders. The peak positions of the emission spectra of Nd 3+ ion in yttria host did not differ with the neodymium ion concentration or the calcination temperatures, whereas the luminescence intensities were heavily dependent on the ion concentration and calcination temperatures.

Nanosized ytterbium doped yttria powders were prepared by citrate-gel combustion techniques. As-synthesized precursor and calcined powders were characterized for their crystalline structure, particle size and morphologies. Nanocrystalline Yb 3+ :Y 2 O 3 powders with pure cubic yttria crystal structure were obtained by calcination of as-prepared precursors at 1100 °C for 3 h. Powders obtained were well dispersed with an average particle size of 60 nm. By using the obtained powders, nearly full dense Yb 3+ :Y 2 O 3 ceramics were produced by vacuum sintering at 1800 °C for 12 h. The emission spectrum of the sintered ceramics under the excitation wavelength of 905 nm illustrates that there are three fluorescence peaks locating at 976 nm, 1030 nm and 1075 nm respectively, all corresponding to the 2 F 5/2 → 2 F 7/2 transitions of ytterbium ion.

Ytterbium-doped yttria (Yb 3+ :Y 2 O 3 ) nanopowders for transparent ceramics were synthesized by using a carbonate-precipitation method. The characteristics of precursor and powders calcined at different temperatures were investigated. The pure yttria phase can form through calcining at 700 °C. The Yb 3+ :Y 2 O 3 nanopowders calcined at 1100 °C were well dispersed with a spherical morphology, and had a narrow particle size distribution with a mean particle size of about 70 nm. By using 1100 °C-calcined powders, nearly full dense Yb 3+ :Y 2 O 3 ceramics were fabricated at 1750 °C for 8 h without any additives under vacuum conditions. The fluorescence spectrum of the sintered ceramics illustrates that there are two emission peaks locating at 1028 and 1071 nm respectively, all corresponding to the 2 F 5/2 → 2 F 7/2 transitions of Yb 3+ ion. Homogeneous Yb 3+ :Y 2 O 3 nanopowders synthesized by carbonate-precipitation method are suitable for the fabrication of IR-transparent ceramics.

We report on the fabrication and characterization of MgZnO/SiO 2 /n-Si structured photodetectors, for the visible–blind monitoring. The current–voltage curve of the heterojunction shows obvious rectifying behaviors. In the visible range, the photocurrent decreased rapidly. In additionally, the ultraviolet/visible rejection ratio (R340 nm/R500 nm) was about four orders of magnitude at reverse bias, indicating a high degree of visible blindness. The key role of the insulating SiO 2 layer will be discussed in terms of the band diagrams of the heterojunctions.

Polycrystalline Nd 3+ and La 3+ co-doped yttria nanopowder Nd 3+ :Y 1.90 La 0.10 O 3 for transparent ceramics was synthesized by co- precipitation method using oxalate acid as the precipitant and (NH 4 ) 2 SO 4 as the electrical stabilizer under ultrasonic radiation. Nanopowders calcined at different temperatures were characterized with thermal gravimetric-differential thermal analysis (TG/DTA), X-ray diffraction (XRD), transmitting electron microscopy (TEM), energy dispersive spectrometry (EDS) and spectral analysis techniques. The results indicated that nanopowders calcined at 1100 °C for 4 h were 40–70 nm in size with spherical morphology, the powder had the strongest emission peak centered at 1078 nm, corresponding to the transition of 4 F 3/2 → 4 I 11/2 of Nd 3+ ion. The highest optical transmittance of the ceramics sintered at 1500 °C for 13 h was about 48% in near IR waveband, and the sintered ceramics had a broad absorption bandwidth of about 12.6 nm at the laser diode (LD) pump wavelength of 808 nm.

Mg 0.20 Zn 0.80 O films have been prepared on quartz substrates by using radio frequency (RF) magnetron sputtering, and metal–semiconductor–metal (MSM) structured photodetectors have been fabricated on the Mg 0.20 Zn 0.80 O films employing interdigital Au as metal contacts. We have investigated the effects of electrode spacings on the properties of Mg 0.20 Zn 0.80 O MSM photodetectors. It was shown that both of dark currents and responsivities of the devices will decrease with the increasing electrode spacing at the same bias. It was thought that the resistance and the depletion region between the electrodes play important roles in the devices, and the physical mechanism can be explained by a straightforward qualitative model.

Y2O3:Eu3+ phosphors co-doped with different metal cations (Li+, Na+, K+, Mg2+, Ca2+) are prepared by the gel-combustion method with Y2O3, Eu2O3, and R(NO3) x (R = Li, Na, K, Mg, Ca) serving as raw materials and glycine as fuel, calcined at 1000 °C for 2 h. The synthesized Y2O3:Eu3+ phosphors doped with different metal cations and doping ratios are characterized by x-ray diffractometry (XRD), fluorescence and phosphorescent spectrophotometer. The co-doping metal cations are advantageous to the development of Y2O3:Eu3+ lattice. All the samples can emit red light peaked at 611 nm under 254-nm excited. The luminescence intensities of co-doping samples are increased because the cations increase the electron transition probability of Eu3+ from 5D0 level to 7F level. The fluorescence lifetime of Eu3+ (5D0 → 7F2) is increased by doping metal cations.

Nanosized green phosphor LaPO 4: Ce 3+, Tb 3+ has been synthesized by microwave-assisted co-precipitation method. The morphology, crystal structure and photoluminescence properties have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and fluorescence spectrophotometer. The lanthanum phosphate phosphors with monoclinic crystal structure and fine crystallinity and dispersibility were synthesized at 900°C for 1 h and the particle size of the phosphors is ∼ 100 nm. The strongest photoluminescence emission peak is located at 543 nm due to the (5D4→7F5) transition of Tb 3+ ion. The experimental results indicate that nanosized green phosphor 40% Ce 3+ and 20% Tb 3+ doped LaPO 4 synthesized by microwave-assisted co-precipitation method is a beneficial phosphor for high resolution display devices.

Y 2 O 3: Eu 3+, Tb 3+ nanopowders were prepared by co-precipitation method with NH 4 HCO 3 as precipitant. The nanopowders with different calcined temperatures and Eu 3+/ Tb 3+ doped ratio were characterized by X-ray Diffraction (XRD), scanning electron microscopy (SEM) and fluorescence spectrophotometer. The results showed that the nanopowders calcined at 1100°C for 2 h had a uniform distribution, high purity and good dispersibility. The particle size was in the range of 60–80 nm. The excitation spectra of Eu 3+/ Tb 3+ co-doped phosphors were wide. The phosphors could emit the green light at the peak of 543 nm and the red light at the peak of 611 nm simultaneously under 276 nm or 300 nm excited. Because of the energy transfer between Tb 3+ and Eu 3+, the 543 nm emission of Tb 3+ ion was weakened while the 611 nm emission of Eu 3+ enhanced. The emissive colors of Y 2 O 3: Eu 3+, Tb 3+ nanopowders could be adjusted from yellow-green to orange-red by changing the Eu 3+/ Tb 3+ doping ratio.

MgxZn1-xO has been an object of intense study as a novel photo-electronic function material in recent years. Mg0.25Zn0.75O film was prepared on quartz glass substrate by sol-gel method. Structure and optical properties of Mg0.25Zn0.75O film were studied both in theory and by experiment. The result indicates that Mg0.25Zn0.75O film has hexagonal wurtzite structure. The film is homogeneous and the average grain size is about 20nm. Absorption spectrum indicates that the absorption edge starts at 360nm and the corresponding forbidden band width is 3.83eV. The luminescence spectrum of the sample is composed of three peaks at 384.9， 444.8 and 533.6nm respectively and the peak of excitation spectrum is at 378nm. The crystal lattice of Mg0.25Zn0.75O film is increased， the forbidden band width is broadened and the ultraviolet and blue-green luminescence peaks red-shift about 59， 14 and 12.6nm， respectively， due to the interstitial defects introduced by the surplus Mg ions.