最新刊期
卷 34 ， 期 3 ， 2013
- 摘要：Er modified electron trapping optical storage materials SrS:Eu0.002, Sm0.002, Erx are prepared by hydrothermal method. The effect of temperature on crystal phase formation, Er content on optical storage and luminescence properties are studied. It is revealed that the Er induced luminescent enhancement and the optical storage properties improved. The maximum luminescence intensity, Photostimulated luminescence intensity and optical storage are obtained at x=0.003, which is as high as 1.9 times, 2 times and 3.5 times of the Er free phosphor, respectively. The introduction of Er didn't change the crystal structure and Photostimulated luminescence decay curve properties of the sample. The photostimulated luminescence decay curve can be will-fitted into a double exponential function.关键词：SrS;electron trapping;optical storage;photostimulated134|42|2更新时间：2020-08-12
- 摘要：Oriented TiO2 nanorod arrays were directly synthesized on fluorine-doped tin oxide glass substrates through a hydrothermal method. Experimental results demonstrate that a number of reaction parameters including acidity, reactant concentration, growth time and reaction temperature can affect the morphology and photocurrent density of TiO2 nanorods. For example, the length of the nanorods significantly increases with the growth time or reaction temperature, while the diameter is only influenced by reaction temperature but not growth time. Photocurrent density firstly improves but then decreases with the reaction temperature, and there are no clear correlations between photocurrent density and growth time. These results will provide helpful information on the optimization of reaction parameters for the synthesis of oriented rutile TiO2 nanorods with high photoelectrical conversion efficiency for solar cell applications.关键词：TiO2 nanorod;dye-sensitized solar cell;hydrothermal method;photocurrent density137|47|0更新时间：2020-08-12
- 摘要：Y2O2S:Tb3+, Eu3+,M2+(M=Mg, Ca, Sr, Ba), Zr4+ white-light long-lasting phosphors were synthesized by the solid-state reaction method. The phosphors were characterized by X-ray diffraction, photoluminescence spectra, long-lasting phosphorescence and thermoluminescence curves. The results show that the doping ions do not change the crystal structure and the situation of emission peaks of phosphors, but influence the intensity, afterglow time and trap depth. Under 263 nm UV excitation, the emission peaks at 469 nm and 626 nm are assigned to the 5D2→7F0 and 5D0→7F2 transitions of Eu3+ respectively, and the peak at 544 nm is assigned to the 5D4→7F5 transition of Tb3+. The white-light can be obtained by the appropriate mixing of them. The afterglow properties of the phosphors doped with different divalent ions decreases according to the order of Mg2+,Sr2+, Ca2+, Ba2+. With Mg2+, the CIE chromaticity diagram was (0.29, 0.32), the trap depth was 1.17 eV and the decay time could last for over 320 s (≥1 mcd/m2). Therefore, the sample doped Mg2+ ion shows the optimal luminescent properties.关键词：white-light long-lasting phosphor;Y2O2S:Tb3+;Eu3+;M2+;Zr4+;rare earths110|16|1更新时间：2020-08-12
- 摘要：Naphthoic acid (NA) ligand was bonded on the side chains of polystyrene (PS) via a polymer reaction, obtaining naphthoic acid-functionalized polystyrene PSNA. The luminous secondary polymer-rare earth complex PS-(NA)3-Eu(Ⅲ) and the ternary complexe PS-(NA)3-Eu(Ⅲ)-Phen were prepared by the coordination of Eu(Ⅲ) ion, respectively, by using PSNA as a macromolecular ligand and small molecular phenanthroline (Phen) as the second ligand. The chemical structures of these complexes were characterized by FTIR and UV absorption spectra, and their florescence emission characters were examined, and especially, the relationship between their florescence emission properties and chemical structures was investigated in depth, and the corresponding microcosmic mechanism was described with Antenna effect theory. The experimental results show that the secondary and ternary complexes formed by the coordination of PSNA and Eu(Ⅲ) ion can emit the strong characteristic fluorescence of Eu(Ⅲ) ion, implying that the NA ligand bonded on the side chains of PSNA can effectively sensitized the fluorescence emission of Eu(Ⅲ) ion. The NA ligand bonded on the side chains of PSNA has stronger sensibilization than benzoic acid (BA) ligand. The florescence emission intensity of the ternary complex is stronger than that of the secondary complex due to the synergism coordination effect of the first and second ligands.关键词：polystyrene;naphthoic acid;Eu(Ⅲ) ion;polymer-rare earth complex;sensibilization101|34|1更新时间：2020-08-12
- 摘要：The luminescence properties of Ce3+, Tb3+ activated BaCa2(BO3)2 phosphors were investigated by vacuum-ultraviolet (VUV) and ultraviolet(UV) spectra. The phase purity was characterized by the powder x-ray diffraction (XRD). The results demonstrate that the band near 140～190 nm range in the VUV excitation spectra is ascribed to the host-related absorption. The lowest 5d state of Ce3+ in BaCa2(BO3)2 is located at 360 nm, and two emission bands from Ce3+ 5d→2FJ(J=5/2, 7/2) were found at about 393, 424 nm. The emission bands of Tb3+-doped BaCa2(BO3)2 consists of four components, which correspond to the 5D4-7FJ(J=3,4,5,6) transitions with the dominant 5D4-7F5 transition at 543 nm. The energy-transfer between Ce3+ and Tb3+ occurs in Ce3+, Tb3+ co-activated BaCa2(BO3)2 phosphors.关键词：luminescence;vacuum-ultraviolet;Ce3+;Tb3+;BaCa2(BO3)2108|38|3更新时间：2020-08-12
- 摘要：The composites of β-NaYF4:Yb3+,Er3+/Tm3+ incorporated in silicate glasses, borate glasses and phosphate glasses were formed into pellets under pressure and annealed under different temperature (400～700 ℃). The effect of different glasses formers and alkali metal ions on solubility and luminescent properties of β-NaYF4:Yb3+,Er3+/Tm3+ microcrystals were characterized by X-ray diffraction (XRD), photoluminescence (PL) spectra. The results show that Li+ ions and K+ ions can replace Na+ ions in β-NaYF4 microcrystals at low heat treatment temperature. The solubility of β-NaYF4:Yb3+,Er3+/Tm3+ microcrystals in different glasses systems is investigated as follows: phosphate glasses>borate glasses>silicate glasses.关键词：β-NaYF4;ionic substitution;solubility;heat treatment;upconversion110|40|0更新时间：2020-08-12
- 摘要：A set of spinel-type Al23O27N5 phosphors co-doped with Mn-Mg were successfully synthesized by solid-state reaction. The results clearly show that the calcination conditions and doping concentration influence the preparation and photoluminescence properties of Mn-doped AlON phosphors. The temperature for obtaining undoped pure phase Al23O27N5 sample is 1 900 ℃ for, while is 1 800 ℃ for 10% Mn and 10% Mg(mole fraction) co-doped samples. The lattice parameter increases with Mn concentration, which suggesting Mn2+ ion doped into AlON crystal lattice. The PL spectra reveal that there exist a broad-band emission from 350 to 600 nm for undoped and all of doped samples. The broad band green emission is observed in 10% Mn and 10%Mg(mole fraction) co-doped sample. The green emission is attributed to the transition of 3d electrons of Mn2+ ion and the blue emission might be related to impurities or Al vacancy.关键词：photoluminescence;pure phase;AlON118|40|0更新时间：2020-08-12
- 摘要：Ba9Y2(SiO4)6:Ce3+,Mn2+ phosphors were prepared by solid-state reaction and their structure, luminescence properties and energy transfer have been investigated by means of XRD, photoluminescence excitation and emission spectra, decay lifetimes, respectively. Upon 327 nm excitation, the phosphor Ba9Y2(SiO4)6:Ce3+,Mn2+ exhibits two dominating bands centered at 407 and 597 nm, originate from 5d→4f transition of the Ce3+ ion and the 4T1g(4G)→6A1g(6S) transition of the Mn2+ ion, respectively. We have discovered energy transfers from Ce3+ to Mn2+. By utilizing the principle of energy transfer, Mn2+ can generate a strong red emission band at 597 nm. The dependence of the ET efficiency can reach to 39% at x=0.25 in BYS:Ce3+, xMn2+. The results indicate that BYS:Ce3+, Mn2+ could be used for UV-based white leds as the red light source.关键词：Ba9Y2(SiO4)6：Ce3+;Mn2+;phosphor;energy transfer;white LED139|50|2更新时间：2020-08-12
- 摘要：Eu single doped and Ce-Tb-Eu co-doped calcium-borosilicate glasses were fabricated by high temperature melting technique. The luminescence properties were investigated by excitation and emission spectra. The emission intensity ratio of Eu2+ to Eu3+ decreased gradually with the increase of optical basicity of the glass matrix. Under 378 nm excitation, blue, green and red emission bands were simultaneously observed at 430, 488, 542 and 612 nm, respectively. By increasing the concentration of Tb3+, a shift of CIE color coordinates from blue to green was observed, and by increasing the concentration of Eu3+, a shift of CIE color coordinates from blue to red was observed. A complex bright white light emitting was obtained with CIE(0.31,0.31) when n(Ce):n(Tb):n(Eu)=0.25:0.25:0.5.关键词：high temperature melting;luminescent glass;optical basicity;white LED109|39|7更新时间：2020-08-12
- 摘要：A new plasma cleaning process for GaAs surface using Ar/H2 plasma was introduced in this paper. The process for Ar/H2 plasma cleaning and surface activation was studied comprehensively to remove various contaminants, oxide layer on GaAs surface, and the influence of Ar/H2 plasma under different plasma parameters was discussed in detail. The results show that GaAs samples treated under the condition of Ar,H2 flow rate 10,30 cm3/min, sputtering power 20 W and cleaning time 15 min give the best cleaning effect, the photoluminescence intensity increases by 139.12%, and the As—O and Ga—O bonds on the GaAs surface decrease greatly.关键词：plasma cleaning;GaAs substrates;photoluminescence intensity109|37|3更新时间：2020-08-12
- 摘要：Thermal management is the challenge of HP-LED packaging. Silver paste is the interconnect material for common LED, but it can hardly dissipate the heat effectively for HP-LED now, especially for multichip HP-LED. Gold-tin (80Au20Sn) eutectic interconnect is a method can improve the heat dissipation, but the eutectic process is complicated as the HP-LED top surface is an emitting surface. In order to investigate the thermal performance improvements of HP-LED interconnected by Au80Sn20, HP-LEDs interconnected by Au80Sn20, solder paste and silver paste are prepared. Firstly, the effects of heating method between bottom and top heating together with bottom heating only are investigated. Secondly, the thermal resistance comparison, the wavelength shift between 50 mA and 1 000 mA, the shear force test are investigated respectively. The results show that the thermal resistance of HP-LED interconnected by Au80Sn20 is obviously lower than that of the HP-LED interconnected by solder paste and silver paste. The wavelengh shift of HP-LED interconnected by Au80Sn20 is the smallest; the shear force results show the HP-LEDs interconnected by Au80Sn20 is the best. Based on the above tested results, the eutectic interconnect process is an effective method to improve the HP-LED heat dissipation.关键词：HP-LED;eutectic interconnect;wavelength shift;thermal resistance102|39|0更新时间：2020-08-12
- 摘要：The antireflective and protective coatings were deposited on the germanium substrates to improve the transmittance and the environmental adaptability. The germanium carbide (Ge1-xCx) coatings were successfully fabricated.The pure germanium was evaporated by the e-gun, and the methane was directly ionized by End-Hall ion source.The different optical constants of the germanium carbide coatings were obtained by controlling the deposition rate and fixing End-Hall ion source parameters. The germanium carbide coatings with different deposition rates were all amorphous tested by X-ray diffraction. The optical constants were calculated by the envelope method from the transmittance data measured by Fourier transform infrared (FTIR) spectrometer. After double-side depositing the germanium carbide coatings on the germanium substrate, an average transmittance Tave>85% was achieved in the long-wave infrared region of 7.5～11.5 μm. After the environment tests, the germanium carbide coating was fine, this indicates the germanium carbide coating has great environmental adaptability.关键词：germanium carbide;long-wave infrared antireflection coatings;ion source assisting;End-Hall ion source107|41|1更新时间：2020-08-12
- 摘要：In2O3 thin-film transistors (TFTs) with different channel thicknesses were fabricated on SiO2/Si substrates by DC magnetron sputtering at room temperature. The effects of the channel thickness on the electrical properties of In2O3 TFTs with bottom-gate configuration were investigated. The performance of devices was found to be thickness dependent. The In2O3 TFT with the optimized channel thickness exhibites enhancement mode characteristics, the threshold voltage is 2.5 V, the current on-off ratio is 106, and the field-effect mobility is 6.2 cm2·V-1·s-1.关键词：In2O3 films;thin film transistor;channel thickness;electrical performance114|42|1更新时间：2020-08-12
- 摘要：Four different structures of dielectric mirror microcavities with a cavity length of one wavelength were designed,and the luminescent properties of the organic layer inside the cavity were simulated and studied. The results show that different DBR structures lead to the change of phase shift of cavity mirror, which can change the device parameters ultimately, such as the transmittance spectrum, standing wave field distribution inside the cavity, and the peak wavelength and intensity of the PL spectra. Only the reasonable design of device structure can enhance the luminescence inside the cavity effectively. The PL spectrum intensity at the harmonic peak can be enhanced about 59 times in the microcavity constituted by symmetry even layer DBR.关键词：dielectric mirror;microcavity;structure design;luminescence119|42|1更新时间：2020-08-12
- 摘要：The laser processing is widely used in the welding of metallic materials, cladding, surface hardening, and other industrial fields. The semiconductor laser has many advantages, such as small volume and weight, high efficiency, maintenance-free, low cost, short wavelength, and so on. In this paper, a 2 218 W high-brightness fiber-coupled module was designed and overall assembled by using 48 conduction cooled diode laser arrays as light-emitting units under a major thoroughfare of industrial water-cooling condition. The emitting wavelength of the diode laser arrays were 808, 880, 938, 976 nm, respectively. The high brightness module can make the flexible manufacturing directly applied in the industrial.关键词：diode bars;fiber coupling;high brightness;beam combiner technology98|39|6更新时间：2020-08-12
- 摘要：GaN-based light emitting diodes (LEDs) were grown on the sapphire substrates with different bow values by low pressure metal organic chemical vapor deposition (MOCVD). LED chips were fabricated and the optic and electronic parameters were characterized. The influence of different bow values on the performances of LED was investigated. The analysis results show that the substrates with bow could relax part of the stress in the epilayer beforehand, which improved the quality of epilayer. Hence, the performances of the LED chips got better. During the growth of LEDs, the InGaN material in the active layer suffered the compressive stress that resulted from the underneath GaN layer. With the increase of bow values, the compressive stress that acted on the InGaN material decreased, which leads to the blue shift of the dominant wavelength.关键词：GaN;LED;bow;residue strain103|41|0更新时间：2020-08-12
- 摘要：Three kinds of electron-blocking layer (EBL) AlGaN based LED were compared numerically. They are conventional AlGaN EBL, AlGaN-GaN-AlGaN (AGA) and gradual Al composition AlGaN-GaN-AlGaN (GAGA) EBL. Their porfermance were analyzed involved carrier concentration in the active region, energy band diagram, electrostatic field and internal quantum efficiency (IQE). The results indicate that the LED with an GAGA EBL exhibits a better hole injection efficiency, a more peaceable efficiency droop, a lower electron leakage, and a smaller electrostatic field than the LED with a conventional AlGaN EBL or with an AGA EBL.关键词：light-emitting diode;electron-blocking layer;numerical simulation;efficiency droop132|42|0更新时间：2020-08-12
- 摘要：High resistance GaN thin film was grown on sapphire (0001) substrates using metal-organic chemical vapor deposition (MOCVD). Effect of the GaN nucleation layer growth parameters, including reactor pressure, species of carrier gas and growth time, on the electrical characteristics of the following grown GaN buffer was investigated. It is found that GaN films epitaxially grown on the GaN nucleation layers deposited at a relatively lower pressure tend to have a high resistance.High resistance GaN buffer layer can also be prepared by extending growth time of the nucleation layer (i.e. increasing the thickness of nucleation layer) or by using N2 instead of H2 as carrier gas during the growth of nucleation layer. GaN layers with a sheet resistance as high as 2.49×1011 Ω/□ was obtained. These layers were used as templates for the preparation of epi-wafers with AlGaN/AlN/GaN hetero structures, which were used to fabricate high electron mobility transistors (HEMTs). The highest mobility of these samples reaches to 1 230 cm2/(V·s).关键词：GaN;high electron mobility transistor;sapphire substrate;MOCVD141|44|0更新时间：2020-08-12
- 摘要：Al/ZnO:Al film structures were fabricated by physical vapor deposition, and the optical properties of which were studied. It was found that Al capped ZnO:Al can enhance the band gap emission and generate blue emission (475 nm). When a 5 nm Ta2O5 spacer was inserted between Al and ZnO:Al, further enhancements were observed for both band gap and blue emission. The enhancement raito decreases with the thickness of the Ta2O5 spacer. Moreover, the band-edge emission and blue emission increase with annealing temperature and the max enhancement ratio is 9 and 83, respectively. According to localized surface plasmon resonance theory, the scattering and absorption cross sections of Al/ZnO:Al were calculated. The theoretical results can interpret the experimental phenomena reasonably.关键词：ZnO:Al films;localized surface plasmon;emission enhancement92|40|0更新时间：2020-08-12
- 摘要：Based on the special properties of thio-base, such as easy to oxidization, alkylation, and the strong absorption of longer ultraviolet wave-UVA, etc., and the anti-tumor activity of nucleoside compounds, a new compound of 4-thio-5-iodouridine was designed and synthesized. The structure was characterized by Infrared spectroscopy, nuclear magnetic resonanceand mass spectrometry. At the same time, the interactions between 4-thio-5-iodouridine and human serum albumin (HSA) were investigated by the fluorescence spectroscopy, ultraviolet-visible absorption spectrum(UV-Vis) and circular dichroism spectrum(CD). The results show that 4-thio-5-iodouridine has a static fluorescence quenching on human serum albumin (HSA). The quenching constants were calculated according to Stern-Volmer equation, and Lineweaver-Burk equation was used to calculate the binding constants. The main forces of both interactions have typical hydrophobic interaction from thermodynamic data to determination. The distance and FRET(fluorescence resonance energy transfer) efficiency between HSA and 4-thio-5-iodouridine were calculated according to Frster resonance energy transfer theory. The conformation of 4-thio-5-iodouridine on human serum albumin was studied using CD.关键词：4-thio-5-iodouridine;human serum albumin (HSA);nucleoside;fluorescence spectroscopy;circular dichroism spectroscopy(CD)122|39|3更新时间：2020-08-12
- 摘要：A flow-injection chemiluminescence (CL) system was developed for the simultaneous determination of ascorbic acid (AA) and rutin (RT) using partial least squares (PLS) calibration. This method is based on that fact that both AA and RT can quantitatively reduce Fe3+ to Fe2+, and that the reaction rates of AA and RT with Fe3+ are different. The calibration curve was linear over the concentration range of 0.1～20.0 mg·L-1 and 0.02～0.6 mg·L-1 for AA and RT, respectively. The limits of detection (LOD) for AA and RT were 8.9 μg·L-1 and 4.5 μg·L-1, respectively, which was calculated according to the International Union of Pure and Applied Chemistry (IUPAC) definition that is 3 times the standard deviation of the blank value. The proposed method was successfully applied to the simultaneous determination of both analytes in pharmaceutical formulations and human urine samples. The results indicate that the method offers the potential advantages of high sensitivity, simplicity and rapidity for AA and RT determination in pharmacy and biological samples.关键词：flow-injection chemiluminescence (FI-CL);partial least squares (PLS);rutin;ascorbic acid116|43|7更新时间：2020-08-12
- 摘要：Considering the significant value of the directional coupler on the integrated optical circuit and optical electronic integrated circuits, two dimensional photonic crystal directional coupler depended on the photonic crystal waveguide was designed. Via the coupling between the bus waveguide and the coupling waveguide, the high efficiency beam splitter of the electromagnetic wave with the wavelength of 1 490 nm and 1 550 nm was realized. The transmission efficiency reached about 93.5%, and the length of the device can be controlled under 30 μm. In addition, it was found that the coupling period was sensitive to the structure parameters of the rods located between the bus waveguide and the coupling waveguide. By stretching the length of the rods to about 0.1a(a is the lattice period) along z direction, the directional coupler with the working wavelength of 1 490 nm and 1 550 nm was designed. The length of the device was about 60 μm, which was much shorter than that without optimizing. The coupling period can be dramatically shorten by stretching the longitudinal length of the rods, which is of crucial value on the decreasing the volume of the device and the achievement of the denser wavelength division multiplexing.关键词：photonic crystal;directional coupler;wavelength division multiplex93|38|1更新时间：2020-08-12
- 摘要：The gold nanoparticles were prepared by the reduction of gold chloride with sodium citrate in aqueous solution and the gold-nanoparticles-doped DNA-CTMA complexes were prepared by ion-change method, and the 4-(9,9-diethyl-2-(pyridin-4-yl)-9H-fluoren-7-yl) pyridine (DPFP) was synthesized via a Suzuki coupling reaction. The gold-nanoparticles-doped DNA-CTMA-DPFP film samples were fabricated by spin-coating the mixed butanol solutions of gold-nanoparticles-doped DNA-CTMA complexes and DPFP. The optical spectra properties and surface enhanced Raman scattering (SERS) characteristics of the film samples were characterized by measuring their absorption spectra, fluorescence spectra, and Raman spectra, respectively. The experimental results show that the absorption of film samples in the range of 300～360 nm are derived mainly from the DPFP dye molecule, whereas the absorption ranging from 500 nm to 700 nm come from the local surface plasma resonance (LSPR) of gold nanoparticles, and the fluorescence spectra exhibits well-defined vibronic peaks at 370 nm (S10-S00 transition), 386 nm (S10-S01 transition), with a shoulder near 408 nm (S10-S02 transition). The Raman spectra of DPFP dye molecule in the film samples were excited by a laser with the wavelength 785 nm, and the SERS peak intensities of DPFP molecule gradually increase as the increases of gold nanoparticles doped into the DNA-CTMA complexes. Therefore, the gold-naoparticles-doped DNA-CTMA films are suitable as the SERS substrates of many dye molecules.关键词：gold nanoparticle;fluorene dye molecule;SERS143|38|2更新时间：2020-08-12
- 摘要：To promote the engineering applications of high power TEA CO2 lasers, the miniaturization and lightweight of the host structure was studied. A new type of host structure with annular flow channel replaced the original cylindrical structure. The way of finite element analysis was used to simulate the stress and deformation of the shell structure. Through the comparison between the two structures on the stiffness, stability and weight, the cassette shell with the ribs which reduced the thickness of shell from 7 mm to 4 mm replaced the shell without ribs. The maximum deformation was reduced nearly an order of magnitude which was from 1.11 mm to 0.126 mm. The developed shell's maximum error between measured deformation and the simulation results was only 1.58%.After measurement, comparing with the cylindrical host, the volume of the new annular flow channel host was reduced by 30% and the weight reduced by 40%. The airflow rate in the discharge zone increased from 84.8 m/s to 97 m/s. After the test of the optic under the same operating para-meters, it is showed that the repetition frequency of the new laser is improved from 400 Hz to 470 Hz and the average output power is improved from 6 800 W to 7 900 W.关键词：TEA CO2 laser;host structure;stress concentration;strain100|38|4更新时间：2020-08-12
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