最新刊期
卷 36 ， 期 11 ， 2015
- 摘要：The luminescent liquid crystals (LLCs) with aggregation-induced enhanced emission can solve the conflicts between fluorescence quenching caused by the aggregation and the requirement of aggregation or self-organization for LCs. A novel LLC, (2Z, 2'Z)-2, 2'-(1, 4-phenylene)bis(3-(4-hexyloxy)phenyl)acrylonitrile (PHPA) was designed and synthesized. The aggregation luminescent properties, solvation effect, thermodynamic properties and emitting anisotropy of PHPA were investigated. The results demonstrate that PHPA has aggregation-induced emission phenomenon and LC phases, and the aligned thin film can emit anisotropic luminescence. It can greatly improve the display technology with a simple device design and substantially increase the device brightness, contrast, efficiency, when the luminescent liquid crystal material is used in LCD.关键词：aggregation-induced emission;luminescent liquid crystals;luminescent anisotropic186|308|8更新时间：2020-08-12
- 摘要：To develop ZnO-based deep ultraviolet (UV) detectors, high-quality ZnO and BexZn1-xO films were grown on c-plane of sapphire substrates using plasma-assisted molecular beam epitaxy (PAMBE). X-ray photoelectron spectroscopy (XPS) tests showed that the mole fractions of Be in BexZn1-xO alloys followed by 1.8%, 4.9%, 8.0%, 15.3%, respectively. Prototypes of ZnO ultraviolet detectors with the metal-semiconductor-metal (MSM) structure were fabricated and tested, which showed a large on/off ratio and high responsivity, as well as the demonstration of blue-shift tuning of responsivity for BexZn1-xO-based detectors with Be doping. The cut-off response wavelength of Be0.153Zn0.847O detectors is 366 nm, moreover, the device has good signal-to-noise up to 2-3 orders of magnitude. These achievements should provide valuable insights and experiences for the ZnO-based materials and devices. Moreover, oxygen plasma surface treatment was studied to probe the influence on dark current. By appropriate surface treatment, the dark current of ZnO detector can be reduced by 4 orders of magnitude.关键词：ZnO single crystal;BexZn1-xO alloy;ultraviolet detector;surface treatment;MBE122|175|0更新时间：2020-08-12
- 摘要：C12A7 :x%Nd3+ powders with unique nanocaged structure were synthesized by self-propagating combustion method. Upon 808 nm excitation, we can observe three peaks at 887, 1 069, 1 340 nm attributed to the transition 4F3/2→4IJ/2(J=9, 11, 13) of Nd3+, respectively. When Nd3+ mole fraction is 0.5%, the intense infrared luminescence can be obtained and no impurity phase is observed. After the annealing in H2 ambient, the encaged OH- and H- concentrations and the grain size of C12A7 increase and the cages are distorted. The improvement of the crystallinity and the decrease of the non-radiative transition rate can enhance the near-infrared luminescence after the annealing in air. Based on the temperature-dependent emission spectra, the high thermal activation energies are obtained, indicating that C12A7 :x%Nd3+ have potential applications in infrared laser.关键词：C12A7;Nd3+;encaged anion;infrared luminescence108|211|1更新时间：2020-08-12
- 摘要：ScVO4 :Eu3+, Bi3+, Al3+ phosphors were synthesized by solid-state reaction at 1 000 ℃ for 6 h. The samples were characterized by X-ray diffraction, FESEM, emission and excitation spectra. Under 315 nm excitation, strong salmon can be observed, which result from the emission band in 590~ 620 nm and the maximum emission peak in 615 nm. The incorporation of a small amount of Al3+ can distinctly enhance the luminescence of the ScVO4 :Eu3+, Bi3+ phosphors, while the excess amounts of Al3+ can make its luminescence weaker. The intensity of (Sc0.81Eu0.05Bi0.10 Al0.04)VO4 phosphor is the strongest, improved 30 times than undoped (Sc0.85Eu0.05Bi0.10)VO4 phosphor.关键词：ScVO4;white LED;phosphors99|124|3更新时间：2020-08-12
- 摘要：InAs/GaInSb superlattice material was grown on (001)GaAs substrates by molecular beam epitaxy (MBE), adjusting the growth temperature and Ⅴ/Ⅲ beam ratio. The results show that the growth temperature is in the range of 385 ℃ and 395 ℃, the Ⅴ/Ⅲ beam ratio is from 5.7 :1 to 8.7 :1. RHEED situ observations to the GaAs layer (4×2), GaSb layer (1×3) and InAs layer (1×2) show clarity reconstructed diffraction fringes, the quality of superlattice structure is better, and with increasing temperature, the carrier concentration and mobility of the material are increased.关键词：InAs/GaInSb;superlattice film;molecular beam epitaxy100|387|1更新时间：2020-08-12
- 摘要：Cu-doped quantum dots (QDs) were used as color converting materials for preparing efficient white light-emitting diodes (LEDs). The Cu-doped QDs synthesized by chemical method showed composition-tunable emission from green to deep red and large Stokes shifts. By using the combination of green light-emitting ZnInS :Cu QDs and red emitting ZnCdS :Cu QDs with blue GaN chips, a high color rendering white LED was fabricated. The resulting three-band RGB QD-white LED exhibits high performance with luminous efficacy of 71 lm/W, color rendering index up to 94, CIE-coordinates of (0.352 4, 0.365 1), and color temperature of 4 788 K. Based on the changes in the photoluminescence lifetimes of Cu-doped QDs, it is found that the energy transfer process from green ZnInS :Cu QDs to red ZnCdS :Cu QDs can be negligible, because the red QDs had no absorption at green band. These results suggest that Cu-doped QDs are promising for solid state lighting.关键词：quantum dots;nanocrystals;Cu-dopedquantum dots;white LEDs;energy transfer118|195|1更新时间：2020-08-12
- 摘要：Hexagonal-phase NaYF4 :Yb, Er/Ho/Tm up-conversion nanocrystals were synthesized using ricinoleic acid (RA) as an sufficient and user-friendly surfactant. The strategy is to form small solid-state crystal nuclei at a lower temperature and then make the nuclei further grow and ripen at a higher temperature. The experiment results show that the structure of NaYF4 :Yb, Er/Ho/Tm nanocrystal is hexagonal-phase with the diameter of 45 nm. The nanocrystals show strong luminescence under the excitation of a 980 nm laser with the average power about 1 W. When the nanocrystals are dispersed in the mixed solution of water and dichloromethane, we can only see a strong green bright beam in water, which demonstrates the hydrophilic characteristic of RA-NaYF4 nanocrystals. The fluorescence property of NaYF4 :Yb, Er/Ho/Tm nanocrystals has no significant change in acidic medium or alkaline.关键词：up-conversion nanoparticles;fluorescence;water-solubility;stability125|60|1更新时间：2020-08-12
- 摘要：Based on the gold nanorods modified by 11-mercaptopropanic acid (MUA) as the skeleton, the low molecular weight polyethylenimine PEI was conjugated to the surface of GNRs/MUA to form GNRs/MUA/PEI nanocomplexes. Firstly, surface modification of gold nanorods was carried out by using MUA to reduce the toxicity of gold nanorods caused by CTAB surfactants, and then further modified by low molecular weight PEI. The large surface area of gold nanorods allows them to carry more genes, which can simultaneously reduce the toxicity of cationic polymer and improve the transfection efficiency of the whole system. GNRs/MUA/PEI were characterized by transmission electron microscopy (TEM), UV-Vis absorption spectra, and Zeta potential. The results show that MUA and PEI are conjugated to GNRs successfully which cause charge reversal on the surface of GNRs, and the optical properties of GNRs are well preserved. In vitro cytotoxic effects of GNRs/MUA/PEI (1.8 kDa) are quantified by MTT assay, and the results suggest that the cell viability is above 75% at the concentration of 300 μg/mL, much higher than the commercialized PEI(25 kDa).关键词：gold nanorods;polyethylenimine;nonviral vectors;cytotoxicity121|387|4更新时间：2020-08-12
- 摘要：Sm3+ doped SnNb2O6 powders were synthesized by molten-salt growth method. The structure and morphology of SnNb2O6 :Sm3+ were characterized by X-ray diffractometer and scanning electron microscope. The photoluminescent properties were studied by the excitation, emission spectra and fluorescence lifetimes. The results reveal that the obtain samples are monoclinic SnNb2O6 powders. Under 407 nm excitation, strong red-orange luminescence can be observed, and the strongest emission peak is located at 599 nm, corresponding to 4G5/2→6H7/2 transition of Sm3+.关键词：molten-salt growth method;SnNb2O6: Sm3+;photoluminesce113|97|2更新时间：2020-08-12
- 摘要：A stepwise hot-injection method was proposed to synthesize CuInS2/ZnS (CIS/ZnS) core/shell quantum dots. Based on CIS quantum dots, the emission bands of the prepared CIS/ZnS quantum dots can be tuned from 570 to 650 nm by varying Cu/In ratio. Compared to the low quantum yields of CIS quantum dots, the quantum yields of CIS/ZnS core/shell quantum dots can reach 78%. The white LEDs with warm tone were successfully obtained via spin-coating CIS/ZnS quantum dots on the yellow phosphor YAG :Ce3+. The experimental results indicate that the white LEDs possess high luminous efficiency of 244.58 lm/W under 10 mA current density. As a result of joining CIS/ZnS quantum dots, the prepared white LEDs display higher color rendering index (CRI) of about 82.7 and warm white light with a correlated CIE parameters of (0.340 6, 0.369 0).关键词：CuInS2/ZnS;core/shell quantum dots;tunable;warm white light103|142|3更新时间：2020-08-12
- 摘要：The influence of cracking selenium on the structure and device parameters of Cu(In1-xGax)-Se2 (CIGS) thin films was investigated. The activity of cracked selenium can be controlled by moderating the temperature of thermal cracking system employed in our self-designed selenization furnace. The HC-Se atmosphere can enhance the Ga concentration on the film surface and increase the band-gap energy of the CIGS film surface. In addition, HC-Se atmosphere can alleviate the "phase separation". Consequently, Voc value of the solar cell increases about 34.6%. The device conversion efficiency using the novel thermal-cracking system increases by about 45.5% from 6.02% to 8.76%.关键词：CIGS;thermal-cracking selenium;open-circuit voltage102|121|0更新时间：2020-08-12
- 摘要：The low-reflectivity Ag/Ge/Ag anode obtained by inserting germanium into sliver is used to fabricate the blue top-emitting organic light-emitting devices. Top-emitting blue emission can be achieved in the device with 100 nm organic layers due to the high phase change on reflection of the anode. The low reflectivity of the anode is helpful to weaken the microcavity existing in the devices, resulting in the angle-stable blue emission. When Ge thickness is 20 nm, the performance of the device is the best. The maximum luminance and current efficiency of the device are 3 612 cd/m2 and 5.4 cd/A, respectively, and its chromaticity coordinates only shift (0.007, 0.006) with the view angle from 0° to 60°.关键词：organic light-emitting device;top-emitting;blue133|273|2更新时间：2020-08-12
- 摘要：The sandwich films composed of aluminum ions doped zinc oxide (AZO)/silver(Ag)/AZO films were prepared on polyimide (PI) and glass substrates by RF magnetron sputtering using the powder AZO target and the solid Ag target at room temperature. The effect of the thicknesses of AZO layers on the structure, optical and electrical properties of the sandwich films was investigated. The results show that the as-deposited films are polycrystalline on both PI and glass substrates. The changes of the electrical properties of the sandwich films are not obvious, and the positions of the highest transmittance shift towards the long wavelength region with the increasing of AZO thickness. When the thicknesses of the films are 30 nm of AZO and 14 nm of Ag, the sheet resistances are as low as 2.6 Ω/□ and 4.6 Ω/□ on glass and PI substrates, respectively. The transmittances of the films at 550 nm are 85% on glass and 70% on PI substrates.关键词：powder target;organic substrate;TCO multilayer film;magnetron sputtering103|202|0更新时间：2020-08-12
- 摘要：In order to improve the efficiency of organic light emitting diodes (OLEDs) working at high current density, a LiF layer was inserted between emiiting layer (EML) and electron transporting layer (ETL) of a C545T :Alq3 based OLED. The external quantum efficiency (EQE) of the device increases with the increasing of the current density. When the current density is 600 mA/cm2, the maximum value of EQE is the biggest of 4.79%, seven times of the reference OLED.关键词：OLEDs;external quantum efficiency;current density;exciton113|252|3更新时间：2020-08-12
- 摘要：Cu doped SnS thin films were grown on the glass substrates by pulsed laser deposition. The targets were pressed by the mixture of SnS and Cu2S powder (Cu and Sn molar ratios were 0%, 2.5%, 5%, 7.5%, and 10%, respectively). The effects of Cu doping content on the microstructural, morphological, optical and electrical properties of SnS thin films were studied by X-ray diffraction (XRD), laser Raman spectrometry, atomic force microscopy (AFM), ultraviolet-visible-near infrared spectrophotometer (UV-Vis-NIR), and Keithley 4200-SCS semiconductor parameter analyzer. The results show that the films grow preferentially oriented in (111) plane, and SnS :5%Cu film has the excellent crystalline and Raman characteristic peaks. With the increasing of Cu doping content, the average particle sizes of the films increase. The absorption coefficient of the film in the visible region is the order of 105 cm-1 for different Cu doping content. The direct band gap of SnS :5%Cu film is 2.23 eV, and the ratio of photo-conductivity to dark-conductivity is 2.59. Finally, p-SnS :Cu/n-ZnS heterojuction device was fabricated on the glass substrate. The device exhibits good rectifying behaviors in dark and under illumination, and weak photovoltaic properties.关键词：SnS thin film;pulsed laser deposition;Cu-doping;heterojuction device100|177|2更新时间：2020-08-12
- 摘要：TFT device with In-Ga-Zn-O (IGZO) film as the active layer deposited by pulse DC sputtering was fabricated. An Al2O3 film which was also deposited by sputtering was sandwiched between the active layer and an insulating layer. The Al2O3 acted as a negative charge layer for threshold voltage modulation (Vth). It raised the Vth from -3.8 V to -0.3 V, enhancing the formation of a depletion mode device. The application of Al2O3 as a negative layer can effectively control Vth around 0 V and enhance the stability of the device. Improved device characteristics such as: on/off current ratio (Ion/Ioff)>109, sub-threshold slope(SS) of 0.2 V/dec, Vth of -0.3 V, and mobility (μ) of 9.2 cm2/(V·s) were therefore achieved.关键词：a-IGZO TFT;MS sputtering;negative charge layer;flat band potential;threshold voltage138|472|1更新时间：2020-08-12
- 摘要：A design scheme of laser protection system based on digital micro-mirror device (DMD) was proposed to reduce the damage of intense laser to optoelectronic imaging equipment. The working principle of the system, the model selection of DMD and CCD, the projection optical path and the design of optical conversion system were introduced in detail. The image pixels were tuned by using the phase-shifting Mohr method. The simulation results show that the system can successfully identify pixel coordinates and radiuses of the laser spot center points in different spot radiuses and light intensities, and achieve micro-mirror control of the corresponding regions of spots. The laser light intensity can be attenuated by over 70%.关键词：DMD module;protection system against laser radiation;phase-shifting Moire method89|147|3更新时间：2020-08-12
- 摘要：Micro-nano hierarchical ZnO structures with superhydrophobic surfaces were synthesized by chemical vapor deposition. The contact angle of the water droplet on the sample surface was 150.7°. The sample structure of micro-column array with nanoneedles on top was confirmed by SEM. By using the AR-G2 Rheometer with step-by-step measurement mode, the relationship between torque and shear rate was obtained by varying the shear rates and spacing. Smooth silicon surface with silane on top and 40% glycerol were used as comparison. The slip length of the surface was 46.8 μm when the shear rate was 20 s-1. This indicates that the surface of micro-nano hierarchical ZnO structures is beneficial to increasing the drag properties of the liquid.关键词：micro-nano multi-scalestructures;ZnO;drag reduction;slip length101|148|0更新时间：2020-08-12
- 摘要：Based on the UV fluorescence phenomena of oil and its products, a multispectral imaging system was constructed. This system was composed of 3 UV excitation light sources, 8 optics filters and a CCD camera. Using this system, multi-spectral images of 6 kinds of oil were collected. The mean of 24 color features of effective light spots was used as the feature set. Then, a novel method called maximize the joint entropy of independent component analysis (ICA) was proposed for K-mean cluster and SVM recognition. It is proved that this method is better than traditional ICA for feature optimized, and the identification rate is 92.3%. This result has positive significance for oil detection.关键词：UV excitation light;multi-spectral imaging;joint entropy of independent component analysis;oil identification102|211|5更新时间：2020-08-12
- 摘要：Because of the excellent properties and wide applications of cinnamamide medicines in clinic, three m-hydroxycinnamic acid derivatives were designed and synthetised by the reaction of m-hydroxybenzoic acid with different amino acids, respectively. Their structures were characterized by mass spectrometry, infrared spectroscopy, and nuclear magnetic resonance. The interaction mechanism of derivatives and human serum albumin (HSA) were investigated by AutoDock molecular docking, fluorescence spectroscopy and UV-visible absorption spectroscopy. The results of molecular docking represent that derivatives exist in the hydrophobic pocket of subdomainⅡA(site Ⅰ) of HSA. Hydrogen bonds and van der Waals' forces are main acting forces and hydrophobic force is just the secondary consideration. The spectra experiment results indicate that the derivatives can form complexes with HSA respectively and strongly quench the intrinsic fluorescence of HSA through static quenching at different temperatures. Meanwhile, the secondary structure of HSA is influenced. The change in enthalpy (ΔH) and entropy (ΔS) suggest that hydrogen bonds and van der Waals forces are main acting forces. The molecular docking data are consistent with experimental results.关键词：cinnamamide derivatives;spectroscopic methodology;molecular docking;human serum albumin (HSA)107|188|5更新时间：2020-08-12
- Address：No.3888 Dong Nanhu Road, Changchun, Jilin, China Postal code：130033
- Tel：0431-86176862 Email：fgxbt@126.com
- Technical support is provided by Beijing Founder electronics co., LTD 吉ICP备11002662号-17
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0