最新刊期
卷 38 ， 期 8 ， 2017
- 摘要：A series of red phosphors NaGd0.95-x(WO4)2:0.05Eu3+,xBi3+(x=0, 0.02, 0.04, 0.06, 0.08)and NaGd0.95-y(WO4)2:0.05Eu3+,ySm3+(y=0, 0.01, 0.02, 0.03, 0.04)were synthesized via hydrothermal process. The structure, morphology and luminescent properties of the samples were characterized by X-ray diffraction, scanning electron microscope and fluorescence spectrophotometer, respectively. The results indicate that the crystal structure of NaGd(WO4)2 is almost not changed by doping a small amount of ions, and all samples are tetragonal scheelite-type pure phase. The particles are square plate in shape, relatively uniform and well dispersive. With the introduction of Bi3+ or Sm3+, the particle size increases from the original 4 μm to 5 μm and 6 μm, respectively. The series of phosphors can be effectively excited under near-UV (at 394 nm), and the strongest emission peak is located at 614 nm which corresponds to the 5D0→7F2 transition of Eu3+. In addition, doping with an appropriate amount of Bi3+ or Sm3+ can improve the luminescence intensity and red-light purity of NaGd0.95(WO4)2:0.05Eu3+ phosphors, especially for Sm3+.关键词：NaGd(WO4)2;red phosphor;hydrothermal method;Bi3+ and Sm3+;sensitized luminescence127|235|4更新时间：2020-08-12
- 摘要：Eu3+-activated Ca1.9 Eu0.1 NaMg2-x Znx(VO4)3 (0 ≤ x ≤ 1) were synthesized by solid-state reaction route, and their photoluminescence and thermal quenching properties were studied. The samples were verified through powder X-ray diffraction, and the target phase was identified with tiny impurity of EuVO4 in the obtained product. Excited by 355 nm, all the samples show the characteristic emissions from[VO4]3- group and Eu3+ ion. With the increment of x value, the intensity of either of the above mentioned emissions increases at first and then decreases, while a red-shifting excitation peak from 347 nm to 356 nm and a decreasing Stokes-shift can be observed. Stronger hybridization effect occurres between the Zn3d orbital and the O2p orbital resulted by the increasing x value which is supposed to be responsible for that phenomena. Furthermore, the x value corresponding to the observed intensity maximum for Eu3+ emission is different from the one for self-activated emission. Their highest difference is observed in the sample of x=1.0. It could be due to an apparently more serious thermal quenching of self-activated emission than that of Eu3+ ion emission. Then, a temperature-sensitive color of the emission is also observed in the samples excited by the near ultraviolet light.关键词：phosphor;alkaline earth vanadate;self-activated emission;Eu3+ ion;photoluminescence thermal quenching111|32|2更新时间：2020-08-12
- 摘要：By adopting three trioctylphosphine (TOP) assisted rapid injection growth method,and combining a composite material for fluorescent quantum dot micro-nano packaging, CdSe/CdS core-shell quantum dots luminescent microspheres (LMS) with thick shell(8.6 ML)were synthesized. It is an organic-synthesis method. The lattice structure, morphology composition and optical properties of the as-prepared, core-shell quantum dots and LMS were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), UV-Vis absorption, photo-luminescence spectrum (PL) and red-light compensation test, respectively. The obtained CdSe core has a cubic phase zinc blend structure. The diameters of LMS are about 45-75 μm with diamond rules of morphology, and the particles disperse in order. The method aforementioned can improve the quantum yield. The quantum yield is improved from 4% (CdSe core) to 48% (CdSe/CdS core-shell quantum-dots). Besides, the luminous power of exciton-states is enhanced, and the fluorescence intensity of CdSe/CdS core-shell quantum-dots is about 13 times larger than that of CdSe core. By applying the LMS and YAG:Ce3+ yellow phosphor combination, the white light-emitting diode (WLED) with high efficiency (148.29 lm/W) and high color rendering index (Ra is 90.1, R9 is 97.0) are obtained. The results indicate that the LMS have good compensation effect for the deep-red-light-band.关键词：LMS;white light-emitting diode (WLED);color rendering index;CdSe/CdS187|144|1更新时间：2020-08-12
- 摘要：Eu doped silicon oxycarbide (SiCxOy:Eu) films were fabricated by magnetron sputtering at a low temperature of 250℃. The excitation mechanism of Eu3+ photoluminescence (PL) from SiCxOy:Eu was investigated. The spectra of all the SiCxOy:Eu films contain two PL bands:the blue band originated from the host matrix and Eu3+ red PL band. With the increasing of the content of Eu from 0.19% to 2.27%, the red PL intensity is enhanced more than three times, while the blue PL intensity gradually decreases. The analysis results of Rama spectra and time-resolved PL show that the blue PL mainly originates from neutral oxygen vacancy (NOV) defect centers in the SiCxOy matrix. Combining with the PLE results, the enhanced red light emission is suggested from the increased concentration of Eu3+ ions and/or the energy transfer between the NOV defect centers and optically active Eu3+ ions.关键词：photoluminescence;europium dopant;silicon oxycarbide;energy transfer129|89|1更新时间：2020-08-12
- 摘要：By using the reverse microemulsion method and P2O5 carbonization method, the fluorescent carbon quantum dots were prepared using pyrolysis by-products tar as carbon precursor. The carbon dots prepared by reverse microemulsion method are regular spherical structures with uniform particle size of 4.3 nm and the crystal lattice spacing is 0.25 nm, corresponding to the (100) plane of graphite carbon. The carbon quantum dots prepared by P2O5 carbonization method are honeycomb-like with particle size of 6.8 nm and the crystal lattice spacing is 0.33 nm, corresponding to the (002) plane of graphite carbon. The yield of carbon quantum dots is 85.3% and 24.3%, respectively.关键词：biomass tar;reverse microemulsion method;P2O5 carbonization method;carbon quantum dots197|159|1更新时间：2020-08-12
- 摘要：To realize spectral beam splitting technology in the bioprocess of hydrogen production by photosynthetic bacteria (PSB), a luminous exothermic biomaterial based on lanthanum hexaboride (LaB6) and chitosan was fabricated. The absorption spectra and photothermal properties of biomaterial with different LaB6 particles were investigated in the visible spectrum. The results show that the biomaterial can transmit the light in the spectrum of 510-650 nm for PSB, and other light energy will convert to heat energy for PSB. In addition, the absorption and photothermal performance of LaB6 particles are significantly effected by the particle size. When the average hydraulic diameter of LaB6 particles in the biomaterial is 296 nm, the rate of temperature rise is 0.41℃/min over 12 min, which is 5.4 times of glass slide.关键词：photosynthetic bacteria;biomaterial;LaB6;photothermal conversion120|134|2更新时间：2020-08-12
- 摘要：In order to solve the biological toxicity of fluorescence resonance energy transfer (FRET) system based on quantum dots, non-toxic ZnS:Cu quantum dots and Rhodamine B were chosen to construct FRET system. ZnS:Cu nanocrystalline quantum dots with good morphology were successfully prepared by precipitation method. On this basis, the fluorescence spectra of ZnS:Cu quantum dots with different concentration of copper and fluorescence spectra of Rhodamine B were tested. Then, FRET system with ZnS:Cu quantum dots as donor and Rhodamine B as acceptor was successfully constructed by the surface modification. Experimental results indicate that the emission spectrum of ZnS:2%Cu matches the excitation spectrum of Rhodamine B most in 481 nm. So the optimum copper doping mole fraction for the construction of FRET system is 2%. The energy transfer efficiency of ZnS:Cu quantum dots as donor and Rhodamine B as acceptor is 25.8%. Further experimental results indicate that the concentration of Rhodamine B also can affect the energy transfer.关键词：ZnS:Cu;rhodamine B;fluorescence resonance energy transfer134|221|1更新时间：2020-08-12
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Preparation and Gas Sensing Characteristics of ZnO Nanowire Arrays Surface-decorated by Pd Particles
摘要：ZnO nanowire (NW) arrays were synthesized by chemical vapor deposition (CVD) method on SiO2/Si substrate. The Pd films with different sputtering time (0-150 s) were uniformly deposited on the surface of ZnO NWs and converted to Pd particles by annealing treatment at 800℃ in Ar gas, and then the gas sensing measurement was performed. The length of the NW is about 15 μm and the diameter is 100-500 nm. For ethanol gas, the optimal working temperature of all gas sensors is 280℃. The increase of the sputtering time (from 3 to 10 s) induces the increase of the number and size of Pd particles, and the response of gas sensor raises from 2.0 to 3.6. Further increase of the sputtering time (from 30 to 150 s) leads to significant increase of the size of Pd particles and the formation of the continuous film, resulting in the significant decrease of the response. All the sensors exhibit the best gas selectivity to H2 gas, and the better properties of the response and recovery time and the response stability are obtained. Finally, the influence mechanism of Pd particle surface decoration on the ZnO NW array gas sensors was discussed.关键词：gas sensing;ZnO nanowire arrays;Pd particle;surface decoration110|171|1更新时间：2020-08-12 - 摘要：The aptamers have been widely used in biomolecule recognition because of their advantages of synthesis, modification and immobilization. The sensing technology developed by surface plasmon resonance(SPR) has the advantages of non-labeling, no pretreatment, real-time monitoring. The sensors based on aptamer and SPR have important application values in biosensing techniques. The applications of biosensor based on aptamer-SPR are reviewed in this paper.关键词：aptamer;surface plasmon resonance;biosensor;detection;application209|376|3更新时间：2020-08-12
- 摘要：Growth and stability properties of rubrene thin films on silicon dioxide substrate were investigated by atomic force microscopy. At a low deposition rate and a low substrate temperature, the rubrene molecules have sufficient diffusion time for the horizontal growth of thin film, and the thin films with better continuity and uniformity can be obtained. However, at a fast evaporation rate and a high substrate temperature, the rubrene thin films change into vertical growth mode, and the dot islands are obtained. The rubrene thin films of horizontal growth show substability properties at annealing and ambient conditions. With the increase of annealing temperature and time under ambient conditions, the spontaneous mass transmission occurrs for the rubrene molecules. The vertical transfer occurrs and the thin films change into dot islands. The model of growth and substability properties of rubrene thin films on silicon dioxide substrate are obtained. The results imply that the force between rubrene molecules and silicon dioxide substrate is weaker than that among rubrene molecules.关键词：Rubrene;deposition rate;substrate temperature;annealing;stability149|267|2更新时间：2020-08-12
- 摘要：Heavily doping beryllium in the InGaAsN/GaAs QW during thermal annealing. An obvious XRD rocking curve peak shift of no-Be QW diffraction towards GaAs substrate peak before and after annealing was observed, while the shift for the Be-doped QW was much smaller than undoped QW.关键词：dilute nitride;molecular beam epitaxy;quantum well;strain relaxation;X-ray diffraction104|128|0更新时间：2020-08-12
- 摘要：ZnO film was commonly used as electron transporting layer(ETL) in inverted polymer solar cell (IPSC) due to its excellent performance. Here, rapid thermal annealing(RTA) was applied to treat the ZnO ETL, and IPSCs with the structure of ITO/ZnO/PTB7:PC71BM/MoO3/Ag were prepared. The ZnO films prepared under different annealing conditions were characterized by atomic force microscopy, scanning electron microscopy, X-ray diffraction,UV-Vis-NIR transmission and photoluminescence (PL) spectra. The power-conversion efficiency (PCE) of IPSC using RTA treated ZnO as electronic transporting layer (ETL) is 8.1%, which is 11.26% higher than that of IPSC with ETL treated by traditional thermal annealing. The ZnO films treated by RTA have good crystalline properties, large grain size and rough surface, which decrease the series resistor (Rs) and increase the short-circuit current density (Jsc), fill factor (FF) of IPEC.关键词：polymer solar cell;rapid thermal annealing (RTA);electron transporting layer;power conversion efficiency (PCE)120|127|2更新时间：2020-08-12
- 摘要：Red phosphorescent organic light emitting diodes were fabricated using R-4B phosphorescent dye. The device structure was ITO/MoO3 (30 nm)/NPB(40 nm)/TCTA (10 nm)/CBP:R-4B(8%) (30 nm)/electron transport layer (40 nm)/LiF(1 nm)/Al(150 nm). The electron transport layers were Alq3, Bphen:Alq3 (x%) and Bphen, respectively. The electroluminescent properties were studied by using different electron transport layers. The results show that the brightness and the current efficiency of the device using Bphen:Alq3 (x%) as electron transport layer is 3.5 times and 1.1-2.5 times respectively stronger than that of using Alq3 or Bphen as electron transport layer. Meanwhile, the efficiency roll-off of device became smooth. Using Bphen:Alq3 as electron transport layer can not only reduce the hopping distance when electrons transmit between LUMO levels, but also restrain the crystallization of Bphen, and as a result, the electron conductivity and efficiency roll-off of the device are improved.关键词：doping;electron transport layer;organic light emitting diode141|87|0更新时间：2020-08-12
- 摘要：In order to study the structure and properties of QLED based on hybrid quantum dots, QLED devices were prepared using red light quantum dots and green light quantum dots as the light-emitting layer, and their properties were characterized. The structure of the device fabricated was ITO/PEDOT:PSS/poly-TPD/hybrid QDs/ZnO/Al, in which three kinds of hybrid quantum dot light-emitting layer were adopted. The red light quantum dot layer was spin coated firstly in the solution 1, followed with spin-coating green light quantum dot layer. The solution 2 first spin-coated green light quantum point layer, red quantum dot layer was spin-coated after that. In the solution 3, red and green quantum dots were mixed with the proportion of 1:1 and was then spin-coated as the light-emitting layer. The experimental results show that the device prepared by the solution 1 has the largest current density, lowest luminous intensity and only exhibit red light. The device prepared by the solution 2 has the minimum current density, and has the spectra of both red and green light. The maximum current efficiency is 4.69 cd/A at the external bias of 8 V. The device prepared by the solution 3 also exhibits red and green light, the current density and the luminous intensity are lower than that of the device prepared by the solution 2. It can be concluded from the energy level that the device prepared by the solution 2 has a double energy trap, therefore, it is advantageous in trapping both holes and electrons to the red light quantum dot layer. It is achievable to further improve the device efficiency by adjusting the thickness of each functional layer to balance the carrier injection.关键词：quantum dot light emitting diode;double energy trap;carrier injection balance158|371|1更新时间：2020-08-12
- 摘要：Based on the three coupled wave equations of stimulated Brillouin scattering and under the condition of small-signal model, the time advancement and pulse distort of fast light in high nonlinear optical fiber were investigated. The results indicate that the time advancement linearly increases and pulse compression becomes larger with the increasing of the input signal power and the transmission distance in optical fiber. Under the same condition, the time advancement occurred in high nonlinear optical fiber is larger than that in single mode fibers, and the maximum advancement of 203 ns as well as small pulse distort are achieved in high nonlinear fiber at the signal power of 50 mW and the fiber length of 50 m. The efficiency of time advancement of fast light in high nonlinear fiber is significantly improved and the pulse deformation is obviously decreased. The research results provide reference for the implementation and application of fast light.关键词：nonlinear effect;stimulated Brillouin scattering;time advancement;pulse compression119|177|1更新时间：2020-08-12
- 摘要：In order to realize remote monitoring or measuring in the way of transmission mode for long period fiber grating (LPFG), the measurement device system based on a single end face coated with reflective film was designed. The sensing principle of LPFG with a single end face coated with reflective film was explained and analysed. The responses of the single end face system and the direct transmission mode system to environmental media with different refractive index were investigated by experiments. Firstly, 2×2 single-mode fiber coupler was used to connect spectrometer, light source and LPFG, respectively. Then, the reflective silver film was fabricated in the other end face of the optical fiber including LPFG. Finally, by measuring a series of environmental media with different refractive indices, the response spectra of LPFG were compared in the two cases of the direct transmission mode and the silver film coated single end face mode. When the wavelength demodulation is adopted, the resonance wavelength corresponding to the same medium is nearly same in the above two cases. When the power/peak demodulation is adopted, the optical loss gradually changed from -6.05 dB to -9.22 dB for the direct transmission mode, but from -8.03 dB to -11.33 dB for the silver film coated single end face mode with the increase of glycerin concentration in solutions. Compared with the direct transmission mode, the relative optical loss of LPFG based on the single end face mode increases significantly. The LPFG in the single end face mode has more sharp resonance peaks than that in the direct transmission mode, which makes the resonance wavelengths and the optical loss value being recognized more easily. The measurement device system based on the single end face coated with silver film not only retains the transmission sensing mode of LPFG, but also makes the operation of measuring environment medium more flexible and convenient. In particular, it has a unique advantage for the measurement of refractive index in long distance, deep liquid, and severe environment.关键词：optical fiber;long period fiber grating;refractive index;silver film;single end face122|188|3更新时间：2020-08-12
- 摘要：In order to meet the demand of high precision of absolute solar spectral irradiance(ASSI) measurement, ASSI measurement and its calibration monochromator were researched. The present situation of ASSI measurement was introduced, and the project of the solar calibration monochromator (SCM) and the solar spectrometer with integrating sphere (SSIS) was emphatically recommended. The SCM and SSIM for ASSI measurement were designed. The absolute calibration of SCM was performed by the space cryogenic absolute radiometer (SCAR), and the measurement data of SSIS was made traceable to the international system of units (SI). The spectral range of SCM covers 300-2 400 nm, the spectral resolution is 3-10 nm, and the uncertainty of solar homochromy power is 0.2%-0.5%. The spectral range of SSIS covers 300-2 500 nm, the spectral resolution is 1-8 nm, and the highest accuracy of ASSI measurement is 0.5%. The results show that the SSIS calibrated by SCAR and SCM can achieve high precision ASSI measurement data.关键词：monochromator;cryogenic radiometer;absolute measurement;space remote sensing127|215|2更新时间：2020-08-12
- 摘要：The effects of hydrostatic pressure on the three-dimensional fluorescence spectra (3DFS) of pure anthracene (10-6 mol·L-1) and its mixtures (anthracene-fluorene, anthracene-naphthalene, anthracene-phenanthrene, anthracene-acenaphthene, anthracene-fluoranthrene, and the concentration ratios are 1:1) were investigated in a pressure range of from 0.1 MPa to 60 MPa at room temperature. The variation of 3DFS under high pressure was revealed by analyzing the positions and intensities of fluorescence peaks with the increase of hydrostatic pressure. It is found that the fluorescence peak shifts are not detected, however, the changes of fluorescence intensities are observed (e.g. anthracene, the fluorescence intensity of peak of 250/382 nm reached its maximum when the pressure was increased to 60 MPa, and the intensity increases 13.6% compared with that of 0.1 MPa). Otherwise, the high pressure fluorescence properties of anthracene are changed profoundly with the addition of other PAHs (e.g. anthracene) is mingled with naphthalene, the fluorescence intensity of peak of 250/382 nm reaches its maximum when the pressure increases to 10 MPa, and the intensity increases 9.35% compared with that of 0.1 MPa.关键词：three-dimensional fluorescence spectra;emission-excitation matrix;hydrostatic pressure;polycyclic aromatic hydrocarbons (PAHs)103|169|1更新时间：2020-08-12
- 摘要：In order to obtain copper ion sensors, a bis-Schiff base containing an azoxy group was synthesized. The complexation effect of the compound on Cu2+ was studied, and the interference of 23 metal ions such as As3+, Mo6+, Mn2+, Zn2+, Fe3+, Pb2+, Al3+, Hg2+, Ni2+, Pt4+, Mg2+, Be2+, Sr2+, Cs+, Os4+, Cd2+, Se4+, Cr6+, Co2+, Rb+, Ba2+, V6+, Ca2+ was also studied in MeOH-H2O by UV-Vis spectroscopy. Job-plot method was used to study the ratio of the Cu2+ complex with the compound. The cooperation mechanism was studied by infrared spectrometry, and the "off-on" nature of the compound with copper ion was studied in EDTA. The results indicate that the bis-Schiff base has a large conjugated system, the structure is novel and stable. The bis-Schiff base shows a highly selective response to Cu2+. A clear color change from colorless to yellow is observed upon the addition of Cu2+ to the solution of the receptor in MeOH by naked-eyes and a single selectivity colorimetric recognition. The Job-plot shows that the bis-Schiff base coordinates with Cu2+ to form 1:1 stable luminescent complex. The UV absorbance of the system shows a good linear relationship with Cu2+ concentration within 1.32-13.0 μmol·L-1, and the detection limit is 2.6×10-7 mol·L-1. The sensing of Cu2+ by this sensor is found to be reversible with the Cu2+ induced color being lost upon the addition of EDTA. The process of titrating Compound 1 with Cu2+ is reversible, and Compound 1 can be used as an off-on switch chemosensor. The complexation mechanism of Compound 1 and Cu2+ was studied by IR spectroscopy, and the binding sites of compound 1 and Cu2+ were identified.关键词：bis-Schiff base;azoxy;copper ion;colorimetric recognition107|85|1更新时间：2020-08-12
- 摘要：A method based on white LED compensated with monochromatic LEDs was proposed to realize the spectrum matching of solar spectrum in the visible range. The market of high-power monochromatic LEDs was researched and the model of joint-density-of-state according to the characteristics of monochromatic LED spectrum was used as the mathematical model. A database was established with the model of joint-density-of-state. Different kinds of monochromatic LEDs combination were optimized to compensate with the white LED by solving non-negative least square solution of overdetermined equation. The reproduction of solar spectrum was achieved. The methods of white LED compensation and multiple monochromatic LEDs spectral assembly were compared and the fitting effect of different LED combination matching solar spectrum was analyzed. The results show that the method of white LED compensated with monochromatic LEDs optimizes the simulated solar spectrum with the fitting correlation index of 90.74%, better than the method of monochromatic LEDs spectral assembly. When the number of LED types decrease, the former has better effect in simulating solar spectrum. The experimental data can be instructive to realize the different degree of solar-like lighting by selecting suitable LEDs.关键词：white LED;monochromatic LED;solar spectrum matching;least square method;correlation index172|128|6更新时间：2020-08-12
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