最新刊期
卷 38 ， 期 12 ， 2017
- 摘要：Two fluorescent groups of quinoline and dansylamide were introduced into ligand L1 together, and a trinuclear zinc metal-organic compound H-1 as a ratiometric fluorescent probe was self-assembled by L1 and zinc ion, and the sensitive recognition of γ-glutamyl-cysteinyl-glycine (GSH) was realized by H-1. The recognition process was studied by UV-Vis, fluorescence spectra, 1H NMR and ESI-MS. UV-Vis adsorption titration results show that the addition of GSH to the solution of H-1 causes a significant absorbance decrease at 425 nm and an obvious absorbance increase at 320 nm. The isobestic point is 355 nm. The equilibrium constant lgK of 4.03 ±0.11 is obtained with the absorbance value at 320 nm. This indicates that 1:1 stoichiometric host-guest complexation of H-1 for GSH is formed. The fluorescence spectra show that the addition of GSH to the solution of H-1 causes an obvious dansyl-based fluorescence decrease at 513 nm upon excitation at 340 nm with a significant red-shift, and an increase of quinoline-based fluorescence at 396 nm. The ratio of dansyl-based fluorescence to quinoline-based fluorescence can be used to detect GSH and the detection limit is up to 2.5×10-6 mol·L-1.关键词：glutathione (GSH);ratiometric fluorescent probe;trinuclear zinc metal-organic compound;recognition177|276|0更新时间：2020-08-12
- 摘要：In order to obtain carbon dots with high quantum yield, a simple two-step solvothermal method was used to prepare fluorescent N-doped carbon dots with citric acid as carbon source and three isomers of phenylenediamine as nitrogen source. The carbon dots were characterized by Transmission electron microscopy (TEM), ultraviolet-visible spectrophotometry (UV-Vis), fluorescence spectrophotometry, Fourier transform infrared spectra (FTIR), X-ray photoelectron spectroscopy (XPS), followed by studying the cytotoxicity and in-vitro bioimaging. The results show that three kinds of high quantum yield carbon dots (Y=52%, 60.4% and 53.2%) possessing uniform size and excellent dispersibility have been successfully prepared, and the average size is 4.5, 5.3, 5.2 nm. The prepared carbon dots with hydroxyl, carboxyl, amine and other groups on the surface can emit bright blue fluorescence under the excitation of ultraviolet light, holding favorable optical stability at the same time. In addition, the cell imaging experiments indicate that the three kinds of carbon dots have good biocompatibility, capable of rapidly entering cells and successfully applied to fluorescence imaging of cells.关键词：carbon dots;high quantum yield;in-vitro bioimaging248|188|5更新时间：2020-08-12
- 摘要：A novel two-photon fluorescence dye 4,4'-((1Z,1'Z)-(9-ethyl-9H-carbazole-3,6-diyl)bis(ethene-2,1-diyl))dibenzonitrile was synthesized, and the linear absorption and fluorescent spectra of the dye in different solvents were investigated. The results indicate that the dye has a intricate solvent effect existing in UV-Vis absorption spectra, and the quantum yields and two-photon active cross-sections in DMSO are 86.02%, 12.56 GM, respectively. About the images, the dye exhibites excellent cell membrane permeability and optical properties. These data show that the compound is a promising candidate for two-photon fluorescence labels.关键词：two-photon fluorescence dye;UV-Vis absorption;quantum yields;active cross-sections;biological imaging142|459|1更新时间：2020-08-12
- 摘要：The NaY(MoO4)2:Er3+ phosphors derived at different calcination temperatures were prepared by molten salt method and the crystal structure and microscopic morphology were characterized by means of X-ray diffraction(XRD) and field emission scanning electron microscopy (FE-SEM). The Stokes fluorescence emission spectra of nanocrystals derived at different calcination temperatures have been measured. It can be found that the emission intensity ratio of 2H11/2-4I15/2 to 4S3/2-4I15/2 transitions from NaY(MoO4)2:Er3+ increases with the decrease of the calcination temperature. Furthermore, the temperature sensing properties of NaY(MoO4)2:Er3+ phosphors were studied based on the emission intensities from two thermally coupled 2H11/2 and 4S3/2 levels of Er3+. The results show that the temperature sensing sensitivity of the sample calcinated at 600℃ is somewhat higher than that of the sample calcinated at 900℃in a relatively wide range of sensing temperature (303-573 K). The sensing sensitivity increases with the decreasing of the calcination temperature, and a relative high sensitivity of 1.36×10-2 K-1 is obtained for the sample calcinated at 600℃, which is about 76.6% higher than that of the sample obtained at 900℃. Finally, the physical mechanism for the calcination temperature-dependence of temperature sensing sensitivity was explained and predicted.关键词：molten salt method;NaY(MoO4)2:Er3+ phosphors;temperature sensing149|207|0更新时间：2020-08-12
- 摘要：UVC (220-280 nm) up-conversion(UC) emission was achieved for the first time under the sunlight. To test UC UVC germicidal efficacy of Pr3+ doped Y2SiO5 phosphors, the verdigris pseudomonad were extracted from soil and used for the experiments. The bacteria were stained by Syto9/PI. Experiment results show that the mortality rate of bacteria adheres to UC phosphor increases markedly under sunlight radiation. It indicates that UC UVC materials can effectively kill bacterium under the sunlight.关键词：Y2SiO5;up-conversion;verdigris pseudomonad;Syto9/PI143|226|1更新时间：2020-08-12
- 摘要：The mechanism of photoluminescence (PL) quenched and lifetime enhanced by semiconductor nanoparticles (SNPs)-metal nanoparticles (MNPs) couple were investigated and the experimental results have been described and analyzed by the conventional Föster resonance energy transfer (FRET). The plasmonically coupled SNPs have demonstrated the PL quenched obviously and lifetime enhanced from 17.7 ns to 30.8 ns, near to 2 times. The hybrid colloidal CsPbBr3 perovskite SNPs/Pt MNPs (S-M) structures exhibit novel optical properties due to the synergetic interaction between the individual components. In hybrid S-M nanostructures, colloidal chemistry incorporates SNP and MNP into a single unit resulting in the formation of plexciton (or excimon) which has now been established in a series of hybrid structures. The experimental results of femtosecond transient absorption (TA) spectroscopy based on the time-resolved pump-probe confirm the transformation from excitons to plexcitons. It was found that the experimental data can't be well described by the theory based on conventional FRET. To modify and improve the conventional FRET is needed.关键词：hybrid CsPbBr3 perovskite/Pt;energy transfer;exciton-plasmon couple;lifetime enhancement176|290|2更新时间：2020-08-12
- 摘要：The ultrafast nonlinear absorption response of GaN and AlxGa1-xN films was studied by employing conventional femto-second Z-scan measurements. In the Z-scan, GaN films exhibit typical two-photon absorption property and with a two-photon absorption coefficient of 3.5 cm/GW. Simultaneously, the two-photon absorption coefficient decreases with the increase of the excitation intensity. GaN films possess excellent nonlinear optical property which is dominated by two-or multi-photon absorption. The Z-scan measurement was further used for AlxGa1-xN films with different Al element content. It is found that the two-photon absorption coefficient of AlxGa1-xN films closely dependent on the mole fraction of Al element. The two-photon absorption coefficient decreases from 18 cm/GW to 5.6 cm/GW with the increase of Al mole fraction from 0 to 0.42. Considering the conventional semiconductor nonlinear absorption theory, it is believed that the observed nonlinear absorption originates from the two-photon absorption dominant nonlinear response. The experimental results are in good agreement with the Sheik-Bahae theoretical prediction for two-photon absorption coefficient.关键词：AlxGa1-xN films;two-photon absorption;band-gap engineering132|342|0更新时间：2020-08-12
- 摘要：To study the spectra of Eu 4f76p3/2ns (n=7, 8) autoionizing states, the isolated-core excitation (ICE) technique was utilized, while the impact of laser polarization on the spectra was studied for the first time. The atom was excited from the ground state 4f76s2 via the first excited 4f76s6p states to the 4f76sns Rydberg states by the first two lasers, which were further excited to the 4f76p3/27s or 4f76p3/28s autoionizing states with the 4f76s+→4f76p3/2+ resonance transition by the third laser. The detailed interpretation to the complex spectra of the 4f76p3/2ns (n=7, 8) autoionizing states was given, from which the spectroscopic information, such as the level energy and line width of the autoionization peak, can be obtained. Furthermore, the configuration interaction among different autoionization series converging to different ionization limits was also observed. Finally, the values of the total angular momentum J of some autoionizing states were identified with different laser polarization combinations.关键词：Eu atom;4f76p3/2ns autoionizing states;spectra;isolated-core excitation;laser polarization118|76|0更新时间：2020-08-12
- 摘要：The charge density, energy band structure, density of states and project density of states of graphene oxide nanoribbons were investigated using the first principle calculations based on density functional theory. The results indicate that the graphene oxide nanoribbons are an indirect band gap semiconductor with an energy gap of 0.375 eV. The charge density is transferred among C, O and H atoms. The project density of states show that the localization and hybridization between C-2s, 2p, O-2p, H-1s electronic states are induced in the conduction band and valence band. The localization is induced by O-2p electronic states at Fermi level. It plays a major role in improving the semiconductor luminescence effect of graphene oxide nanoribbons.关键词：graphene oxide nanoribbons;energy band;project density of states;first principle calculations227|699|2更新时间：2020-08-12
- 摘要：In-Sn-Zn oxide thin-film transistors were deposited at different nitrogen flow rates on P-Si <100> substrate by RF magnetron sputtering. The influence of nitrogen on the structure, optical and electrical properties and stabilities of ITZO TFTs was studied. The results show that nitrogen has no obvious effect on the structure of ITZO films and all thin films are amorphous. The average transmittance of all ITZO films approach or exceed 90% in the visible region and the optical band gaps are 3.28-3.32 eV. When the nitrogen flow rates increase to 4 mL/min during the sputter deposition, the ITZO TFTs with low interface state density(~4.3×1011 cm-2) show excellent electrical properties, the sub-threshold swing is 0.39 V/dec and on/off ratio is 106 operated with the field-effect mobility(μFE) of 18.72 cm2/(V·s). Moreover, the TFTs show better stability than others in the positive gate bias stress test. Overall, the suitable addition of nitrogen can improve the electrical performance and the stability of the ITZO TFTs by the passivation of oxygen vacancies and the drop of interface state density.关键词：ITZO TFTs;RF magnetron sputtering;nitrogen doping;interface state density133|132|1更新时间：2020-08-12
- 摘要：The photoluminescence quantum efficiency evolution of CH3NH3PbI3 films was studied in this paper. During the light soaking the photoluminescence quantum efficiency of CH3NH3PbI3 films increases first, then decreases gradually. The photoluminescence dynamics measurement shows that the carrier recombination lifetime changes synchronously with that of photoluminescence quantum efficiency. According to the above experimental phenomena, we propose that the light soaking induces two processes of opposite direction to CH3NH3PbI3 films. One process would increase the photoluminescence quantum efficiency of CH3NH3PbI3 film, and the other one would reduce its photoluminescence quantum efficiency. Both processes determine the evolution of photoluminescence quantum efficiency of CH3NH3PbI3 films together.关键词：light soaking;CH3NH3PbI3;photoluminescence quantum efficiency;defect;passivation106|313|1更新时间：2020-08-12
- 摘要：High efficient green phosphorescent organic light-emitting diodes (OLEDs) were fabricated based on semiconductor heterojunctions of C60 and CuPc as the anode modified layer. Compared with the reference device based on MoO3 as the anode modified layer, the maximum current efficiency and EQE for C60(5 nm)/CuPc(25 nm) planar heterojunction modified device are improved by 12% and 11%, reaching up to 60 cd/A and 16.8%, respectively; and the values for CuPc:C60(50%, 30 nm) bulk heterojunction based device are increased by 26% and 27%, arriving at 67 cd/A and 19.3%, respectively. On one hand, the superior device efficiency based on heterojunction modified layer can be attributed to efficient dissociation and hole injection of accumulated charges generated in the heterojunction interfaces driven by the external electrical field. On the other hand, the higher efficiency is also attributed to the photovoltaic effect of heterojunction which can utilize the green photon to produce photon-generated carriers. Due to the more efficient charge accumulation and more proper carrier transport property, more balanced recombination of carriers and better photovoltaic effect, the bulk heterojunction modified device owns the higher efficiency comparing with the planar heterojunction modified device. The study demonstrates that the organic semiconductor heterojunction can become a kind of superior anode modified layer.关键词：organic semiconductor heterojunction;anode modified layer;efficiency;phosphorescent organic light-emitting diodes205|138|0更新时间：2020-08-12
- 摘要：PBDT-TT-F:PCBM based heterojunction red photodetectors were fabricated by the experimental method combined with spin coating process and vapor deposition process. The effects of the mixing degree and thickness of the active layer, the annealing temperature and other factors on the photoelectric properties of the device were studied. The experimental results show that the performance of the device is the best with the mixing mass ratio of PBDT-TT-F:PCBM of 1:1.5, the thickness of 150 nm, the annealing temperature of 100℃, and the annealing time of 15 min, respectively. The photocurrent density of the diode is 0.85 mA/cm2, and the light response is 128 mA/W.关键词：organic detectors;red light;active layer;photoelectric characteristics130|124|3更新时间：2020-08-12
- 摘要：An unintentionally doped AlSb/InAs quantum well (QW) structure and a Si-δ doped quantum well structure on GaAs (001) substrates were grown by molecular beam epitaxy (MBE). The dependence of sheet electron density and electron mobility on the measurement temperature were investigated. It is found that electron mobility as high as 25 000 cm2·V-1·s-1 has been achieved for 300 K in the Si-δ doped quantum well structure. The Hall devices with high sensitivity and good temperature stability were fabricated based on the Si-δ doped AlSb/InAs quantum well structures. Their sensitivity is markedly superior to Hall devices of an unintentionally doped AlSb/InAs quantum well.关键词：Hall device;quantum well;δ-doping;molecular beam epitaxy147|115|0更新时间：2020-08-12
- 摘要：Base on multiple single emitters using spatial beam combining as well as fiber coupling techniques, a high-power and high-brightness fiber-coupled laser-diode module with 9 single semiconductor laser emitters at 915 nm inside was fabricated. It was demonstrated both by ZEMAX software simulation and experiment. The module can produce more than 110 W output power from an optical fiber with core diameter of 105 μm and numerical aperture (NA) of 0.22 with equalizing brightness of 8.64 MW/(cm2·sr). The compactness, higher efficiency, and lower cost production of the diode are available through this technique, and much wider applications of fiber-coupled laser-diodes are anticipated.关键词：laser coupling;laser beam shaping;laser beam combining;diode lasers163|119|0更新时间：2020-08-12
- 摘要：The electrostriction coefficient can be accurately measured by using small length variation based on inverse piezoelectric effect. The conventional optical measuring method based on direct detection of light intensity distribution to obtain small length variation is restricted by light source power stability and environmental perturbation, and can not reach high measuring accuracy. This paper uses the combination of multi-beam laser heterodyne technique with sinusoidal modulation technique to load small length variation to the heterodyne signal frequency. By researching on the theoretical models of heterodyne signal for measuring small length variation, and the relationship between heterodyne signal frequency and electrostriction coefficient, the direct intensity detection can be replaced by heterodyne signal frequency detection, the effects of light source power stability and environmental perturbation can be removed. Many values of small length variation can be got by using the frequency demodulation simultaneously. Processing these values by weighted-average, can get length variation accurately, and eventually get value of electrostriction coefficient of piezoelectric material by the calculation. The measuring accuracy of electrostriction coefficient can be further improved. Based on this, the theoretical simulation research on electrostriction coefficient of testing sample can be acted, the obtained results show that the relative measurement error of this method is just 0.28%. The measuring accuracy is improved one order of magnitude compared with existing technique.关键词：electrostriction coefficient;laser heterodyne;sinusoidal modulation;Doppler effect;piezoelectric material266|145|1更新时间：2020-08-12
- 摘要：Based on the equivalent medium theory, an square aperture nano-hemisphere structure with bottom surface fill-factor of 100% and spherical vector height of 320 nm was designed and put into use in the course of experiment as it sought to make GaN-based LED more efficient. Guided by the finite-difference time-domain method(FDTD), a simulation research on how the parameters of structure influenced the light extraction efficiency performance, such as the spherical vector height, the bottom surface fill-factor was schemed to be conducted in the experiment. The study provided the evidence that the optical light extraction efficiency could be achieved on the occasion that the square aperture nano-hemisphere array with a radius of 320 nm and a bottom surface fill-factor 100% p-GaN was etched and presented on the surface of LED. Such technologies as electron beam exposure combined with thermal reflow and ICP etching should be applied and come into service for building square aperture nano-hemisphere arrays. In strict accordance with calculation results, under the working current of 20 mA and 150 mA, the luminous efficiency of the LED with the nano structure is 4.67 times and that of the reference sample is less than 4.59 times, which shows that square aperture nano-hemisphere array promises to help make the light extraction efficiency of LED better, according to the electroluminescence test.关键词：LED;finite-difference time-domain method;nano-hemisphere;light extraction efficiency;electroluminescence129|244|2更新时间：2020-08-12
- 摘要：To realize the characters of a dual-band filter that selectively transmit light of wavelengths of 0.83-0.87 μm but cut off the wavelengths of 0.5-0.68 μm and 0.73-0.79 μm on a 45° incident angle on K9 substrate, a type of F-P bandpass filter was chosen to be the initial structure which effectively reduce the number of the thin film compared with the routine design concept. The high index material of titanium oxide (TiO2) and the low index material of silicon oxide (SiO2) were used during the course. The thickness of 23 layers was 2.278 μm. The electron beam physical vapor deposition (EBPVD) was used to fabricate the coatings. The transmittance of the sample was measured by using the spectrophotometer. The average cutoff depth is 12.57% and 20.39% corresponded to the band from 0.5 μm to 0.68 μm and the band from 0.73 μm to 0.79 μm respectively from the test result. The average transmittance is up to 91.35% for the pass band from 0.83 μm to 0.87 μm. It appears almost the same with the designing result that the figure of transmittance shifts to the short wavelength by 10 nm. Beyond this, the edge filter cuts off in dual-band and gets the high transmittance in pass band. In the environmental tests, the coatings match well with each other which is remarkably stable. So, the dual-band cut-off edge filter can be applied in extreme cases.关键词：optical thin film;electron beam physical vapor deposition(EBPVD);filter262|213|3更新时间：2020-08-12
- 摘要：Under the physiological condition of pH 7.4, using ethidium bromide (EB) as the fluorescent probe, the interaction mechanism between coriolis (Cor) and calf thymus DNA was studied by UV-Vis absorption spectroscopy, resonance scattering spectroscopy combined with salt effect and DNA melting point. Cor can quench the fluorescence of EB-DNA system through a static process. The subtractive effect of the characteristic absorption peak occurrs after Cor interacts with DNA. The interaction leads to the enhancement of Cor resonance at 481 nm and a new resonance scattering peak at 330 nm. The salt effect has a little influence on the interaction between Cor and DNA. The interaction leads to the increase of the Tm of DNA by 5.5℃. It is deduced that the main way of the interaction between Cor and DNA is intercalation, and a supramolecular system is formed between them. The binding constant (KA) between Cor and DNA is 5.82×103 L/mol (298 K) and 2.47×104 L/mol (310 K). The interaction between Cor and DNA is entropy-driven spontaneous, endothermic. Hydrophobic forces are the main non-covalent mode of action.关键词：corilagin;calf thymus DNA;spectra method;intercalation;reaction mechanism111|247|1更新时间：2020-08-12
- 摘要：Liquid-crystal lenses are new devices for free 3D display, its photoelectric properties are controlled by electric field. The accurate design and optimization method of lens parameters were presented in this paper. Based on the optical software ZEMAX and the focal length zoom method, the parameters of LCDs were designed and optimized. Then, the aberration of liquid crystal lens and image quality were evaluated. it is proved that the optimized liquid crystal lens aberration decreases evidently. The dispersion spot root mean square radius (RMS) value decreases from 248.118 μm to 62.192 μm with 3.5° view and the optical modulation transfer function MTF is improved. The experimental results show that the brightness and clarity of the diffractive lens array are significantly improved.关键词：liquidcrystal lens;modulation transfer function(MTF);optical design;image evaluation185|351|3更新时间：2020-08-12
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