最新刊期
卷 40 ， 期 12 ， 2019
- 摘要：Near infrared spectroscopy and imaging technology had been applied in fields such as food analysis, early diagnosis of cancer, and brain science. However, this technology was still suffered from lacking of broad band near infrared (NIR) light source. To solve the problem, phosphor converted broad band NIR LED (pc-LED) developed into a promising solution. This review summarized recent progress on the decisive material of NIR pc-LED:Cr3+ doped broad band NIR phosphors. Applications that demanding broad band NIR source, technology of current broad band NIR source, and luminescence property of Cr3+ were introduced. Some important topics for Cr3+ doped broad band NIR phosphors, such as efficiency, band width, electron-phonon coupling, and application, were also discussed. This review will help readers to understand recent progress, problems, and future of Cr3+ doped broad band NIR phosphors.关键词：LED;near infrared light;phosphor;Cr3+;broad band1472|1700|30更新时间：2020-08-12
Invited Paper
- 摘要：Mo2N/TiN composite thin films were prepared by ammonia reduction nitridation method using titanium tetrachloride and molybdenum pentachloride as materials. The composition, morphology and surface enhanced Raman spectroscopy of the composite films were studied through XRD, XPS, SEM, UV-Vis and Raman testing. The results indicated that the TiN and Mo2N coexisted in the composite film. With the increase of molybdenum pentachloride content, there was an obvious resonance absorption peak in the range of 400-600 nm, and the absorption peak intensity and peak width increased. The surface enhanced Raman spectroscopy properties of Mo2N/TiN composite films were studied using Rhodamine 6G as probe molecule. When the addition amount of the molybdenum pentachloride was 6%, the Raman enhancement effect of the composite films was the best, and the detection limit was 10-5 mol/L. Raman enhancement factor was 0.31×103. Meanwhile the surface enhanced Raman performance decreased only 20.76% after it was stored in air for 6 months. At the same time, the composite films had high temperature stability, and they still had surface enhanced Raman characteristics after annealing at 500℃, therefore, they have the potential of reuse as SERS substrate.关键词：molybdenum nitride;titanium nitride;composite film;surface enhanced Raman spectroscopy(SERS)204|562|2更新时间：2020-08-12
- 摘要：A series of activators Tb3+, Sm3+ and Tb3+/Sm3+ ions doped Ca9Al(PO4)7 phosphors were synthesized by high temperature solid-state method. The characteristics of phosphor were recorded by X-ray diffraction, luminescence and fluorescent decay curves. Under 380 nm excitation,the 5D4-7F6-3 of Tb3+ emission lines and 4G5/2-6H5/2-9/2 of Sm3+ orange emission lines can be observed from Ca9Al(PO4)7:Tb3+,Sm3+. When increased Sm3+ contents, the orange-red emission intensity of Sm3+ can be enhanced by the efficient energy transfer from Tb3+ to Sm3+ ion, and the electric dipole-dipole interaction is responsible for the energy transfer. The best quantum efficiency of Ca9Al(PO4)7:Tb3+,Sm3+ is 50.6%. The results indicate that it may be the potential application to ultraviolet-pumped white light emitting diodes.关键词：luminescence;phosphor;energy transfer;Ca9Al(PO4)7:Tb3+;Sm3+175|222|2更新时间：2020-08-12
- 摘要：Lu2O3(Y2O3):Yb3+/Er3+/Gd3+ phosphors were synthesized using a sol-gel method.Upconversion(UC) luminescence and temperature-sensing properties were investigated. Under 980 nm excitation, bright green, red, and weak ultraviolet emissions were observed. The optimal Gd3+ doping concentrations in Lu2O3(Y2O3) was 10%. The energy transfer processes from Er3+ to Gd3+ ions has been investigated and discussed. By utilizing the fluorescence intensity ratio (FIR) technique, the temperature sensing behaviors of the optimal sample are investigated based on the thermally coupled levels of 2H11/2 and 4S3/2 of Er3+ ions from 313 K to 573 K. The maximal sensitivity was gained to be 0.005 91 K-1 for Y2O3:1%Er3+/1%Yb3+/10%Gd3+.关键词：sol-gel method;fluorescence intensity ratio;sensitivity172|195|3更新时间：2020-08-12
- 摘要：Yb3+ and Ho3+ codoped hexagonal GdInO3 phosphor has been synthesized by hydrothermal process and further heat treatment. The crystal structure and phase purity were checked by means of powder X-ray diffraction (PXRD), and the refinement results showed that pure phase GdInO3:Yb3+/Ho3+phosphors were obtained. The morphology of the synthesized materials was characterized by SEM and TEM. The upconversion (UC) luminescence properties of the phosphor were investigated. Green emission at 539 nm (5S2/5F4→5I8) and red emission at 665 nm (5F5→5I8) of Ho3+ were observed upon 980 nm laser excitation. Moreover, it has been found that tuneable emission characteristics from green to yellow were obtained via the Ho3+ concentration modulation. The tunable emission is due to the cross-relaxation process (5F4/5S2+5I7→5F5+5I6). The GdInO3:Yb3+/Ho3+ can be a good candidate for upconversion material in lighting and display fields.关键词：hydrothermal;rare-earth;perovskite;phosphor;upconversion170|208|2更新时间：2020-08-12
- 摘要：In order to study the variation of anosilicate phase composition and luminescence properties with the ternary alkaline ion ratio, high-efficiency phosphors are preferred. The internal mechanism of luminescence properties in single-phase and mixed-phase regions is also discussed and component-structure-luminescence properties are established. (Mg1-x-yBaxSry)1.95SiO4:0.05Eu phosphors were synthesized by high temperature solid-state reaction, a total of 44 samples. By the analysis of binary and ternary powders' phase constitutions and the luminescent spectra, the phases and the ultraviolet excitation luminescence CIE values were obtained. The experimental results showed that the phases of (Mg1-x-yBaxSry)1.95SiO4:0.05Eu is gradually changed with compositions, Ba2SiO4-phase region is formed on the Ba-rich corner(the maximum amount of Sr is 35%, and Mg is 30%). The lattices of Ba2SiO4-phase powder decrease and the crystallines increase as the Sr2+ and Mg2+ content increasing. (Mg1-x-yBaxSry)1.95SiO4:0.05Eu phosphors also have a gradually changing in photoluminescent color and intensity under the ultraviolet excitation. Ba2SiO4-phase powders are green phosphors and the intensity increases with Sr2+ or Mg2+ substitution. High resolution emission spectra indicate that Sr2+ or Mg2+ substitution promotes Eu2+ in taking place of Ba2+(I)(the relative higher luminescent efficiency site).The binary series of Mg2SiO4-Sr2SiO4 matrix powders activated by Eu ion are red phosphors. The other mixture-phase phosphors would gradually change from green to red as decreasing of Ba content (Eu ion trends to be +3 for coordination space gradually decreaseses). For (Mg1-x-yBaxSry)1.95SiO4:0.05Eu series, relationship both the structure and luminescent properties changes with composition. Profiting from the essence of the phase diagram, a ternary color image could be created, and used to screen the candidates. It should be an efficient and systematic approach to make the phosphor discovering(optimized green and red phosphor sample points are:((Mg0.3Ba0.65Sr0.05)1.95SiO4:0.05Eu and (Mg0.65Sr0.35)1.95SiO4:0.05Eu).关键词：alkaline earth silicate;europium ion;phase diagram;luminescent;CIE135|92|0更新时间：2020-08-12
- 摘要：A novel near-infrared luminescent material Mg2-xSnO4:xCr3+ was synthesized by high temperature solid phase method. The structure of the sample was characterized using X-ray powder diffractometer. It was proved that the obtained phosphor had a single spinel structure, and the addition of doping ions did not significantly change the crystal structure. The luminescent properties of the samples were investigated using fluorescence spectroscopy and fluorescence decay spectroscopy. When excited at 470 nm, the phosphor exhibits a sharp emission at 700 nm and a strong broad band emission centered at 750 nm, which belong to the 2E→4A2 and 4T2(4F)→4A2 transitions of Cr3+respectively. The effects of Cr3+ doping concentrations on the luminescence properties of the samples were investigated. It was found that the luminescence intensity of the samples increased with the increase of Cr3+ concentration and reached its maximum at x=0.02. Then luminescence intensity quenching occurred and the quenching mechanism is the electric dipole-electric dipole interaction. The fluorescence lifetime of the sample decreases with the increase of Cr3+ doping concentration, which proves that there is energy transfer between Cr3+ ions. The Mg2-xSnO4:xCr3+ phosphors also exhibit near-infrared long-lasting luminescence properties.关键词：Mg2SnO4;near infrared luminescence;fluorescent material;optical properties;afterglow304|273|5更新时间：2020-08-12
Synthesis and Properties of Materials
- 摘要：To analyze the optical-electrical-thermal characteristics of white LEDs, effects of temperature and current on the spectral power distribution of the white LED were tested under the controllable heatsink temperature and current. On the basis, prediction models for spectral optical power and blue-white ratio (the ratio between blue optical power and white optical power) of the white LED were proposed. Correlation analysis proved that the blue-white ratio was highly correlated with the correlated color temperature (CCT) as well as circadian action factor (CAF). Moreover, linear relationships both exist between blue-white ratio and CCT, and between blue-white ratio and CAF. It indicates the possibility which qualitatively predicting color temperature drift and non-visual biological effects of the white spectrum from changing spectral power distribution. Experimental results show that, the maximum prediction errors of spectral optical power, blue-white ratio, CCT and CAF of the white LED were within 4.22%, 1.54%, 1.31% and 2.15%, respectively. Meanwhile, the spectral blue-white ratio can be used as an effective method to predict CCT and CAF of the spectrum, and thus to evaluate the spectral optical properties and non-visual biological effects.关键词：white LEDs;optical power prediction;color temperature drift;circadian action factor;non-visual biological effects221|910|4更新时间：2020-08-12
- 摘要：A LD side-pumped high-energy, high-beam-quality, electro-optic Q-switched all-solid-state Nd:YAG laser with thermoelectric cooler is developed. The size of the crystal in the oscillator is φ7 mm×100 mm and the Nd atomic ratio is 1.1%. The maximum peak power of pumping LDs is 15 kW. At the repetition rate of 10 Hz, the oscillation output with the maximum pulse energy of 350 mJ is obtained with the pulse width of 9.7 ns, the beam quality M2 of horizontal and vertical directions is 3.3 and 3.8, respectively. The MOPA structure is used to improve the final output power. The dimension of the Nd:YAG crystal in the first amplifier is φ7.5 mm×134 mm, when the pumping current is 80 A and the width of pumping pulse is 200 μs. A 700 mJ, 10 ns laser pulse is obtained with the repetition frequency 10 Hz. The dimension of the Nd:YAG crystal in the second amplifier is φ8 mm×100 mm and the pumping current is 80 A. The maximum output pulse energy is up to 1 085 mJ with the pulse width of 10 ns. The energy instability is less than 3%, the beam quality M2 of the horizontal and vertical directions is 3.9 and 4.8, respectively. The miniaturization and water-free of high beam quality Nd:YAG laser at Joule level are realized.关键词：pulse laser;LD side pump;MOPA;electro-optic Q switched249|433|4更新时间：2020-08-12
- 摘要：For convenient and accurate adjustment of ultra-low color temperature of 8-bit LED backlit LCD, the fill color RGB value was set through the Adobe Photoshop, display color blocks on LED backlit LCD, combined with self-made blue light absorption film of mobile phone screen, achieving ultra-low color temperature adjustment. 1931 CIE-XYZ standard chromaticity system color coordinate Z value, color tolerance, main wavelength, color purity, peak wavelength, centroid wavelength, half peak width, color rendering index Ra of LED backlit LCD, were studied by spectral analysis. We realized 8 bit LED backlit LCD 1 000 K ultra-low color temperature adjustment. The average relative error of the 10 measured 6 500-1 000 K color temperatures and the target color temperature is 0.349%, the average absolute error is 7.1 K, which can guarantee the white balance. According to the spectral analysis, after adding the self-made blue light absorption film of mobile phone screen, the centroid wavelength will decrease by 15 nm on average at the same color temperature. When the color temperature is less than 4 100 K, the half-peak width of the same color temperature is about 4 nm smaller. The other six parameters have little influence. The method and conclusion are valuable for optimizing the effect of anti-blue light film and the research of LCD.关键词：liquid crystal display;three primary colors;color temperature;spectral analysis142|475|0更新时间：2020-08-12
- 摘要：This paper proposes a method of white light mixed for red/green/blue/warm-white (R/G/B/WW) light emitting diode (LED) based on pulse width modulation (PWM). According to the principle of linear superposition of the relative spectral power distribution (SPD) of multi-color white LED, the proposed model adopts 1931 CIE-XYZ tristimulus to determine the relationship between the color coordinate and the rate of contribution for each channel of the LED clusters. When the color rendering performance is optimized, the functional relationship between luminous flux and duty cycles of the mixed light is established. And the experimental verification is carried out with R/G/B/WW LED clusters. The experimental results show that R/G/B/WW LED model can realize that the color rendering index Ra is larger than 95 and its maximum relative error is 1.35%, the correlation color temperature (CCT), the luminous flux and the luminous efficiency change in the range of 3 000~7 000 K, 200~1 000 lm, 170~240 lm/W, respectively.关键词：optical device;pulse width modulation;light-emitting diode;high color rendering index234|244|2更新时间：2020-08-12
Device Fabrication and Physics
- 摘要：In this paper, a chitosan derivative(CS-g-CA) was synthesized by using citric acid and chitosan as main raw materials, N-hydroxysuccinimide(NHS) and N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride(EDC) as coupling agents. Then, the chitosan derivative polymer dot fluorescent material P(CS-g-CA) Ds was synthesized by hydrothermal method using CS-g-CA and the doping reagent N-(2-hydroxyethyl)-ethylenediamine. The P(CS-g-CA)Ds was characterized by fluorescence, ultraviolet spectroscopy(UV), transmission electron microscopy, photoluminescence spectra.The quantum yield and fluorescence lifetime of the test P(CS-g-CA)Ds were 54.7% and 13.12 ns, respectively, indicating that the polymer carbon dots have good fluorescence properties. When P(CS-g-CA)Ds was applied to metal ion detection, it was found that P(CS-g-CA)Ds had good selectivity to Pd2+ with a detection limit of 63.3 nmol/L. The fluorescence quenching mechanism of Pd2+ on P(CS-g-CA)Ds was studied by UV spectroscopy, fluorescence lifetime and quenching constant at different temperatures. The results show that the quenching mechanism is static quenching.关键词：chitosan;polymer carbon dots;fluorescent material;ion detection;Pd2+188|169|0更新时间：2020-08-12
- 摘要：Using the stannous chloride as raw materials, we synthesized a SnO2 quantum dots by the means of hydrothermal method in this paper. The synthesis conditions such as pH, temperature, as well as time were optimized, and the FT-IR, XRD, Malvern Zetasizer Nano ZS90, FL-4600 fluorescence spectrophotometer etc. were utilized for the physicochemical and optical properties characterization of SnO2 quantum dots. The experimental result shows that the size of SnO2 quantum dots is about 5 nm, when excited with 310 nm light, the maximum emission peak of SnO2 quantum dots locats at 415 nm. In the presence of Fe3+, the fluorescence of SnO2 quantum dots is quenched, while the Fe2+ has no affection on the fluorescence of SnO2. Utilizing the reduction of ascorbic acid (AA), the Fe3+ ions can be reduced to Fe2+, resulting in the fluorescence restore efficiently. When the concentration of AA is 500 μmol·L-1, the fluorescence recovery can reach to 95.88%. Based on this, we constructed a novel off-on fluorescence probe based on SnO2 quantum dots for the sensitive detection of AA.关键词：tin oxide quantum dots;fluorescent probes;AA detection156|229|0更新时间：2020-08-12
- 摘要：This paper was aiming to explore the feasibility of the combined model of hyperspectra on soil heavy metal content. Taking the reclaimed soil in Gulin, Sichuan Province as the research object, the samples were collected and the contents of heavy metals (Cd, Cr, Ni, As and Hg) and spectral information were measured. The soil spectrum was preprocessed to explore the response band; PLS, ANN and RF were used to construct a single estimation model, and entropy method was used for better model combination. The results showed that the correlation between heavy metal content and spectrum was improved by four kinds of spectral pretreatment techniques. The single prediction model MSC-RF had the best effect and could predict the heavy metal content to the maximum extent. Compared with the single prediction model, the combined prediction model constructed by the entropy value method has an improved effect, and the verification set R2 reaches a maximum of 0.91. It was showed that the combined model could make use of sample information of multiple single models to a large extent, reduce the influence of random factors in a single model, enhance the stability of the model, and play a better role in the prediction of heavy metal content of soil in abandoned mining land.关键词：mining wastelands;soil heavy metals;hyperspectral;entropy method;combination model164|235|4更新时间：2020-08-12
- 摘要：The sugar content of red grapes is an important index to measure its internal quality. The conventional methods based on biochemistry to test the sugar content are all destructive. This article proposed a method using high spectrum technology for sugar content test which does not break the fruit at all. The spectral and graphical information is collected and extracted from 260 samples. PLSR model was set up by the usage of preprocessing method like SNV and S-G, which is aiming to find out the fittest one. We adopted six algorithms including GA, CARS and IRIV from one-time dimension-reducting algorithm and CARS-SPA, IRIV-SPA and GA-SPA from combined dimension-reducting algorithm respectively, to extract the characteristic variable from the spectral information. 19 characteristic parameters were obtained from the texture information of images by gray-level co-occurrence matrix and the color information respectively by RGB model. After reducing the dimensions of image information with PCA algorithm, we built the linear predictive model PLSR and non-linear predictive model LSSVM, which were based on the dimension-reduced spectral information, image information and the combination of the formers separately, then compare the efficiency of models. The results show that, when we modeled with spectral information merely, the IRIV-SPA was able to extract the characteristic wavelength of the spectrum information of red grape's sugar content; comparely, the model built with information of images only did not work well, even though the PCA that reduced the dimensions effectively increased the performance of model's prediction but limitedly. We built the PLSR model and LSSVM model with both spectral wave-range characteristics by IRIV-SPA and image information dimension-reduced by PCA. The correlation coefficient of optimal PLSR model's calibration set and prediction set is 0.943 and 0.941 respectively while 0.954 and 0.952 for LSSVM model. The performance of model of LSSVM was better than PLSR, but the former one took more time for operation. The relatively greater promotion on accuracy of both models based on the combination of two classifications of characteristics indicated that the combination of spectral information and image information was not just able to increase the operating speed and simplify the model but effectively promote the performance of the prediction for red grape's sugar content. Thus a new method for the detection of red globe grape sugar content was found.关键词：red globe grape;hyperspectral imaging;sugar content;information fusion;nondestructive testing159|250|5更新时间：2020-08-12
Luminescence Applications and Interdisciplinary Fields
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