最新刊期
卷 36 ， 期 2 ， 2015
- 摘要：LaF3 nanocrytals with different Nd3+ concentration were designed, synthesized and modified by oleic acid. This kind of nanocrystals can be dissolved in many organic solvents and form a transparent, uniform and stable solution. The structure, crystal phase and luminescence properties of LaF3:Nd3+ nanocrytals were characterized and studied. The nanocrytals show strong emission at 1 060 nm not only in solid but also in solution. This illustrates that the nanocrystal lattice can efficiently protect Nd3+ ions from the influence of environment on the luminescence. Meanwhile, the absorption loss and scattering loss of LaF3 nanocrystals in organic solution were tested by our own system. The total loss coefficient can meet the requirements for laser medium material. These results show that LaF3:Nd3+ nanocrystals may be used for liquid laser medium in the future.关键词：rare-earth;nanocrystal luminescent materials;coprecipitation method;liquid laser medium107|49|0更新时间：2020-08-12
- 摘要：With the development of LED technique, red-M2Si5N8(M=Ca, Sr, Ba) phosphors gradually become an important kind of three-primary-color phosphors. With the increasing of the patent applying amount, the broad application prospects of M2Si5N8 phosphors have received great attention at home and abroad. To understand the application status of M2Si5N8 phosphors comprehensively and promote the development of research and technique ultimately, this paper firstly reviews the patent applying amount over the years, important applicants and technical evolution of basic patents on preparing the phosphors. The synthesis methods are classified and compared. The creative points are concluded. The paper may be helpful for those persons in the field to acquire recently technical development on related industries, develop and protect valid patents.关键词：phosphor;preparation;patent review;M2Si5N8140|104|0更新时间：2020-08-12
- 摘要：Carbon particles were synthesized in aqueous solution of the biological reagents D-(+)-glucosamine-HCl and glucose. The structure and composition of synthesized carbon particles were investigated using field emission scanning electron microscope, high-resolution transmission electron microscope, micro-Raman spectroscope and Fourier transform infrared spectroscope. The results indicate that the carbon particles are formed in the spherical shape and amorphous structure with diameter of 0.3-1.4 μm. The photoluminescence (PL) of carbon particles were studied in micro-Raman spectroscopy using the 325 nm line of He-Cd laser. The PL spectra show a weak blue PL band centered at 420 nm and two strong and wide green and red PL bands centered at 575 and 650 nm, which are related to the functional groups and the transition between two bands. The broadening of green and red PL bands is related to the diversity of sp2 clusters.关键词：hydrothermal synthesis;carbon particles;photoluminescence86|63|1更新时间：2020-08-12
- 摘要：Classical blue-green excitable CaS:Eu2+ phosphor with desired red emission was synthesized by microwave (MW) field with a high frequency of 2.45 GHz. The phosphors can be excited in a wavelength range from 410 nm to 580 nm. In particular, the phosphors exhibit a 476 nm excitable 654 nm peaked red emission. The effect of MW power on material crystal structure, particle size, morphology and luminescent properties was researched by varying the firing power of MW. It has been established that the dielectric property of materials affects MW heating process. MW power supply acts as an effective indicator to predict the viability of dielectric property of materials due to the MW energy. The results show that the variation of MW power can not affect the crystal field of Eu2+ in lattice matrix. It is obvious that the phase purity, particle size, and morphology are different with the variation of applied MW power. The phase purity CaS:Eu2+ phosphor with smaller particle size can be obtained in the MW power range of 1.0 kW to 1.1 kW. However, the samples contain CaO impurity phase and the particles are severely agglomerated in the MW power range of 1.2 kW to 1.3 kW. In conclusion, a maximum PL intensity at 1.1 kW of MW power is acquired for the obtained purer host phase.关键词：microwave firing;phosphor;calcium sulfide98|76|1更新时间：2020-08-12
- 摘要：The nanoporous alumina films were prepared by two-step anodic oxidation in ethanol-oxalic acid mixture. The scanning electron microscope (SEM) measurements reveal that the synthesized films have highly ordered pore arrangements. The photoluminescence (PL) measurements show that the PL intensity of the film has been significantly improved comparing with the films prepared in the oxalic acid, and the PL intensity increases with the ethanol concentration. The reasons for the above experimental phenomena were discussed combining the infrared reflectance spectroscopy with X-ray photoelectron spectroscopy. This work will provide a new idea for doping in the nanoporous alumina film and improving its luminescence property.关键词：nanoporous alumina films;ethanol;photoluminescence95|99|0更新时间：2020-08-12
- 摘要：Highly luminescent carbon quantum dots (CQDs) were prepared by using L-ascorbic acid as a carbon source derived from reverse microemulsion. This method could control the CQDs size directly by adjusting water-surfactant molar ratio without other procedure. Hexadecylamine was used to functionize CQDs. The synthesized CQDs had high quantum yield of maximum 47% at the 360 nm excitation wavelength and the particle size could be tuned by changing the molar ratio of the water to surfactant from 20 to 50.关键词：CQDs;reverse microemulsion;size tunability117|74|2更新时间：2020-08-12
- 摘要：The amino modified β-NaY(Gd)F4:Yb3+/Er3+ nanorods were synthesized by hydrothermal synthesis process using polyethyleneimine (PEI) as a surfactant. The preparation method and conditions of β-NaY(Gd)F4:Yb3+/Er3+ upconversion nanorods were also studied. The pure β-NaY(Gd)F4:Yb3+/Er3+ upconversion nanorods can be obtained at 200 ℃ for 8 h with Gd3+mole fraction of 40%. The crystal structure, morphology and luminescent properties of final products were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM) and fluorescence spectra (PL), respectively. The as-synthesized samples presented a pure phase β-NaY(Gd)F4:Yb3+/Er3+ nanorods with average diameter of 40 nm and average length of 210 nm. Under 980 nm excitation, four upconversion emissions centered at 407, 529, 546, 660 nm were observed, corresponding to 2H9/2→4I15/2, 2H11/2→4I15/2,4S3/2→4I15/2 and 4F9/2→4I15/2 transitions of Er3+, respectively. The amino groups on the surface of β-NaY(Gd)F4:Yb3+/Er3+ upconversion nanorods can be coupled with bovine serum albumin (BSA) via a glutaraldehyde method, and the coupling was confirmed by UV spectroscopy and Coomassie brilliant blue method at room temperature.关键词：β-NaY(Gd)F4:Yb3+/Er3+;up-conversion luminescence;bioconjugation102|38|0更新时间：2020-08-12
- 摘要：A series of hydroxyapatite (HAP) materials doped with different content of europium (Eu3+) were synthesized by one-pot wet-chemical precipitation method. They were calcined under different temperature. The structure, composition and luminescent property were characterized. XRD patterns and IR adsorption peaks showed the characteristic structure and corresponding groups for Eu doped HAP samples. The typical emission peaks attributed to Eu ions were observed in emission spectra of HAP:xEu samples under 394 nm excitation. The luminescent intensity of Eu doped samples was enhanced firstly and then decreased after 500 ℃ calcination. Meanwhile, the fluorescent lifetime of doped samples increases with the temperature. Furthermore, the ratio of intensity between 618 nm and 595 nm corresponding to electric-dipole and magnetic-dipole transition (IR:IO) increases firstly and then decreases at 600 ℃, which revealed that the proportion of substitute type and site of Ca ions by Eu ions were helpful to realize the substitute process and functional structure design.关键词：hydroxyapatite;europium doping;calcination temperature;fluorescent lifetime107|77|0更新时间：2020-08-12
- 摘要：Bi2S3/BiOCl composite photocatalysts with various mass fractions of Bi2S3 were successfully synthesized by a facile hydrothermal process at 433 K, characterized by various techniques, and evaluated by the photo-degradation of methyl orange (MO) in an aqueous solution under the irradiation of ultraviolet (UV) light. The results showed that the photocatalytic activity of Bi2S3/BiOCl catalysts was greatly enhanced, compared with that of pure Bi2S3 and BiOCl. Especially, the photocatalytic activity of the 26.5%Bi2S3/BiOCl sample is very close to that of commercial Degussa P-25 (TiO2), which has been generally recognized as an efficient photocatalyst under UV light irradiation. The remarkably enhanced photocatalytic activity could be mainly attributed to the effective transfer of the photo-generated electrons and holes at the heterojunction interface of Bi2S3 and BiOCl, which reduced the recombination of electron-hole pairs.关键词：hydrothermal method;Bi2S3/BiOCl;composite photocatalysts;methyl orange97|55|1更新时间：2020-08-12
- 摘要：Li4-3xEux(MoO4)2 microcrystallines were synthesized by hydrothermal method. The crystal structure, surface morphology and room temperature photoluminescence properties of the microcrystallines were investigated by X-ray powder diffraction (XRD), scanning electron micrograph (SEM) and fluorescence analysis (FL), respectively. XRD results confirm that the obtained Li4-3xEux(MoO4)2 microcrystallines are all typical scheelite structure with tetragonal symmetry. SEM images show that the grain size of Li4-3xEux(MoO4)2 microcrystalline decreases with the increasing of x, varies in the range of 0.2-0.5 μm. Fluorescence analysis results reveal that the two strong emission peaks attribute to the transitions of 5D0→7F2 and 5D0→7F1 of Eu3+ ion (located at 592 nm and 614 nm ) appear obviously, and the emission intensity of the latter is much higher than that of the former. With the increasing of x, the emission intensity of the two characteristic emission peaks of Eu3+ ion initially increase, reach the maximum at 1.0, and then decrease.关键词：Li4-3xEux(MoO4)2 microcrystallines;hydrothermal method;preparation;luminescence properties104|64|4更新时间：2020-08-12
- 摘要：The influence of sputtering pressure on the structure and device performances of Cu(In1-xGax)Se2 (CIGS) thin films is investigated. The crystalline and roughness of precursors can be moderated by choosing appropriate sputtering pressure, which may facilitate Ga incorporation into the lattice during the selenization process. With the sputtering pressure increases, the precursors tend to be amorphous state and become denser. As a result, the selenized films may display "phase separation" of CIS and CGS which results in decrease of Voc and FF, and the cell efficiency drops from 10.03% to 5.02%.关键词：sputtering pressure;roughness;CIGS solid solution96|59|0更新时间：2020-08-12
- 摘要：MgZnO films were prepared by RF MBE equipment. X-ray diffraction, UV-visible transmission spectroscopy and X-ray energy dispersive spectroscopy indicated that MgZnO films had a single hexagonal phase structure with a shap absorption edge at ~340 nm, and the composition ratio of Zn and Mg was 62:38. Au electrodes were deposited on MgZnO thin films by an ion sputtering apparatus with a mask and Au-MgZnO-Au UV detectors were fabricated. Au electrodes thicknesses could be modified by changing the sputtering time. With the increasing of Au electrode thickness, the conductivity of Au films increased slowly at first, then increased rapidly, and slowly to saturation finally. As for the transmittance of Au films, it decreased nearly linearly with the increasing of Au electrode thickness. In addition, with the increasing of Au electrodes thickness, the responsivity of MgZnO UV photodetectors gradually increased at first, and then decreased. When the thickness of Au electrode was 28 nm, the device has the best responsivity.关键词：MgZnO;UV detectors;Au electrode;thickness108|72|4更新时间：2020-08-12
- 摘要：An asymmetric porphyrin derivative of 5-(4-aminophenyl)-10, 15, 20-triphenyl-porphyrin (H2ATPP) has been successfully covalently connected to photo-permeable mesoporous silica thin films as a unit to mimic logic function. This hybrid mesoporous structure is not only advantageous to the interaction between inputs and response materials, but also to separation of the response materials and inputs without information lost. Then molecular logics with the function of memory, based on its characteristic of being sensitive to acid and base, are achieved. With different initial states, it could be handily described as feedback loop for sequential logic.关键词：porphyrin;molecular logic;mesoporous silica thin film;covalently connected;feedback loop102|86|0更新时间：2020-08-12
- 摘要：In order to reduce the off-state leakage current and increase the on/off current ratio in ZnO thin-film transistor (ZnO-TFT), Si-doped ZnO thin-film transistors (SZO-TFTs) and TFT with SZO/ZnO acted as dual-active-layer were fabricated by magnetron sputtering method. Effects of silicon concentration on optical transmittance of Si-doped ZnO thin film and electrical properties of SZO-TFT were investigated. Moreover, the electrical characteristics of the TFT with SZO/ZnO acted as dual-active-layer were compared with those of the TFTs with ZnO and Si-doped ZnO acted as single-active-layer. The experimental results indicated that, compared with undoped ZnO-TFT, the off-state leakage current of SZO-TFT reduces by more than two orders of magnitude, down to 1.5×10-12 A, and the on/off current ratio increases by more than two orders of magnitude with a maximum value up to 7.97×106; The SZO/ZnO dual-active-layer architecture used in the ZnO-based TFT could increase the on/off current ratio by about two orders of magnitude with no reduction in carrier mobility, and thus optimize the performance of the ZnO-based TFT.关键词：thin film transistor;zinc oxide;silicon doping;dual-active layer95|71|0更新时间：2020-08-12
- 摘要：Composite material titanium dioxide doped tris(8-hydroxyquinoline)-aluminium (TiO2-Alq3) was applied in organic lighting emitting diodes (OLED) as emitting material. Without encapsulation, it is found that TiO2-Alq3 as emitting layer in OLED exhibits significantly improved anti-aging performance than that of the pure Alq3-based OLED. It can be attributed to the introduced of TiO2, which has good photochemical stability and the absorption ability in UV, etc. The OLED with optimized anti-aging performance was obtained after tuning the molar ration of reactants tetrabutyl titanate and aluminium sulfate to 1:10. After aging 48 h in the air, the luminance and current efficiency of this optimized OLED still remained in the initial state of 89.7% and 79.6%, respectively. This work paves a new way to improve the anti-aging performance of OLED by modifying the emitting materials.关键词：Alq3;TiO2;composite materials;OLED;anti-aging90|73|2更新时间：2020-08-12
- 摘要：Non-silica fibers have the intrinsic limitations in high power supercontinuum generation. High power mid-infrared supercontinuum generation in silica photonic crystal fiber is firstly investigated in our studies. The dispersion of fiber is designed to be beneficial to supercontinuum broadening to mid-infrared region. Meanwhile, to withstand high pumping power, a relatively large core diameter is essential. On the premise of supercontinuum broadening to 3.4 μm, fiber length is optimized to reduce the loss of the optical fibers. The results show that it is feasible to generate supercontinuum spectrum with 20 dB-bandwidth covering from 1 550 nm to 3 420 nm by injecting 1.95 μm picosecond pulse into silica photonic crystal fiber with appropriate dispersion. The average power of the supercontinuum spectrum can reach 56.6 W.关键词：nonlinear optics;mid-infrared;supercontinuum spectrum;silica photonic crystal fiber107|81|4更新时间：2020-08-12
- 摘要：Ag and SiO2 films were prepared by RF magnetron sputtering layer by layer. Ag nanoparticles diffused towards and mostly assembled near the surfaces of composite films via ripid thermal treatment. The effects of the thickness of each Ag film, the thermal treatment time, temperature and process on the Ag particle morphology were investigated. The relationship of Ag particles density with the resonance absorption was researched, too. It is found that different Ag particle shapes can be obtained by changing the thickness of each Ag film. The smaller Ag particles can be obtained by intermittent thermal treatment. The Ag particle density and particle uniformity can be improved by annealing at 500 ℃. The result in this paper is different from previous reports. Namely, the surface plasmon resonance absorption of Ag particles does not significantly decrease with the decreasing of particle size, even improves. It is found that the higher the density of the Ag particles is, the larger of the difference between the particle surface energy level and Fermi level is. With the migrating of the electrons from the particle interior to the surface, the electron number to form new Fermi level E'F increases, so the surface plasmon resonance absorption becomes stronger. Finally, we draw a conclusion that the metal particle resonance absorption not only relies on the metal particle size, but also greatly relies on the particle density.关键词：particle density;surface plasma;thermal treatment;Femi level;resonance absorption124|70|1更新时间：2020-08-12
- 摘要：In order to research the relationship between the light environment of ship cockpit indicator and the colors of the instrumental equipment, we did the dark adoption and color discrimination experiments and analyzed the experimental results. According to the process of Chinese shipbuilding industry for light environment and dark adaptation, the rules for the ship pilots' sense of distinguishing color in different light environments were concluded based on the experiments and analysis. We set the subjective ability for color recognition and the changes of environmental light as the measurement indexes. The experimental results show that red＋white LED is the most appropriate light source used in the ship cockpit, which can not only satisfy the dark-adapted conditions, but also improve the color recognition ability of the pilot. Therefore, the red incandescent lamp that is used in the ship cockpit to improve the dark adoption ability of the pilot should be mixed with white lamp to improve the color recognition ability of the pilot, and the brightness (L*) of the indicator instrument color should be ruled in the range of 50-80. In this way, the probability interpretation of instrumentation and error operation of ship pilots can be reduced efficiently.关键词：ship lighting;visual ergonomics;dark adaptation;light environment111|66|1更新时间：2020-08-12
- 摘要：In order to evaluate the effects of space radiation on the imaging function of a CMOS active pixel sensors (APS) manufactured in a 0.5 μm CMOS N-well technology, 60Co-γ radiation experiment was conducted for the overall circuit and pixel unit of the device, and the effects of the total dose on the main parameters of the device were analyzed. When the total dose of irradiation reached a certain value and during annealing, the dark signal, saturated output signal and pixel unit output signal were measured quantitatively off line. The mean dark signals dramatically increase with the total dose. The saturation output signal decreases with the total dose, being consistent with the output signal of the pixel unit saturation. It is found that the degradation of the device parameters is caused mainly by the radiation induced charge in LOCOS(Local oxidation of silicon) isolation oxide layer.关键词：total ionizing dose;CMOS APS;saturation output signal;pixel unit;LOCOS isolation95|39|5更新时间：2020-08-12
- 摘要：We report a large two-photon absorption (TPA) in ZnO/ZnS and ZnO/ZnS/Ag core/shell quantum dots (QDs). Z-scan and pump-probe techniques with femtosecond laser pulses were employed to characterized the quantum dots. The intrinsic TPA coefficients of ZnO-based core/shell QDs are enhanced with nearly three orders of magnitude compared to that of ZnO bulk counterpart, which is attributable to quantum confinement effect. The TPA cross-section of ZnO-based nanocomposites is determined to be ~4.3×10-44 cm4·s·photon-1 at the wavelength of 660 nm. This value is at least two orders of magnitude greater than that of ZnS, ZnSe, and CdS QDs. Due to the local field effect, the nonlinear absorption in ZnO/ZnS core/shell QDs is improved as beaded with Ag nano-dots.关键词：two-photon absorption;ZnO/ZnS core/shell quantum dots;Z-scan technique99|77|0更新时间：2020-08-12
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