最新刊期
卷 35 ， 期 4 ， 2014
- 摘要：By incorporating suitable amount of H dopants and lowering the Al contents, the conflicts between low resistivity and high transmission in transparent conducting films have been successfully solved. The reduced resistivity of ZnO:Al films by hydrogen doping is attributed to the increased carrier density and carrier mobility. Hydrogen behaves as a shallow donor in ZnO and can provide plenty of electrons. Most importantly, it can increase the carrier mobility effectively by lowering the potential barrier between ZnO grains due to the passivation of O- defects around grain boundaries. The carrier mobility can also be increased due to the less impurity scattering induced by the lowering of Al dopants in ZnO films. With hydrogen doping, low resistivity (6.3×10-4 Ω·cm) ZnO:Al samples with only 1/10 of Al contents compared to conventional AZO films can be got. The optical transmittance in near infrared region(1 200 nm) increases from 64% to 90% by comparing samples without and with H-doping is shown. This kind of high conductivity and high transmittance ZnO thin film will be excellent transparent conducting oxide candidate for various types of thin-film solar cells to improve the efficiency of the device.关键词：H/Al co-doped ZnO;free carriers absorpion;magnetron sputtering;thin film solar cells81|99|1更新时间：2020-08-12
- 摘要：A series of nitrogen-doped zinc oxide (ZnO:N) thin films were grown on c-plane sapphire substrate by plasma-assisted molecular beam epitaxy. Due to the large number of donor defects, the samples grown in the continuous zinc-rich atmosphere showed n-type conductivity. In order to suppress the compensation effect caused by donor defects, by periodically supplying oxygen during the growth and then alternating the growth atmosphere in the growth process, the conflict between nitrogen doping level and intrinsic defects was relaxed partly. Compared to the case without supplying oxygen, the crystal quality of the thin films was improved. And the photoluminescence measurements showed that the oxygen vacancy and the zinc interstitial defects in the thin films were suppressed significantly. The samples showed a high repeatability of p-type conductivity. The carrier concentration of the samples grown by alternating the growth atmosphere can reach 1016 cm-3. This may be an effective method to realize the p-type doped ZnO.关键词：ZnO;p-type;oxygen supplementation124|99|2更新时间：2020-08-12
- 摘要：Ag nanowires and ZnO quantum dots were fabricated by chemical methods. The surface morphologies, structures and optical properties were investigated. It is found that both Ag nanowires and ZnO quantum dots exhibit single crystal structure with average diameters of 160 nm and 5 nm, respectively. The enhanced ultraviolet photoluminscence was observed from ZnO quantum dots after mixed with Ag nanowires. The enhancement ratio is 30-fold for emission at 345 nm and 12-fold for that at 383 nm. These enhancement emission positions coincide with the localized surface plasmon resonant absorption peaks of Ag nanowires, which indicate that there are two localized surface plasmon resonant modes in Ag nanowires. This work may give a new approach to design ZnO based nano light-emitting devices.关键词：ZnO quantum dots;Ag nanowires;localized surface plasmon173|311|2更新时间：2020-08-12
- 摘要：Ba5(PO4)3Cl:Eu2+ phosphors were synthesized by a high temperature solid state reaction with Eu2O3, NH4H2PO4, BaCl2·2H2O, and BaCO3 as the raw materials. The crystal structure and luminescent properties of the samples were analyzed by the X-ray diffraction and the fluorescence spectrophotometer. The results show that Ba5(PO4)3Cl:Eu2+ phosphors synthesized are pure, the excitation spectrum contains a broad band in a range of 245~425 nm, and the emission band locats in 400~500 nm, indicating Ba5(PO4)3Cl:Eu2+is a blue phosphor under near UV excitation. Eu2+ concentration affects the luminescent intensity of Ba5(PO4)3Cl:Eu2+ phosphor synthesized seriously. The emission intensity firstly increases and then decreases as Eu2+ content increases. The emission intensity reaches the maximum when the doped Eu2+ concentration is 3%.关键词：Ba5(PO4)3Cl：Eu2+;LED;luminescent property;blue phosphors136|153|1更新时间：2020-08-12
- 摘要：Tb3+ doped Bi2O3-B2O3 glasses were prepared by melting technique, and the relationship of optical basicity,luminescence properties and structure were investigated by excitation, emission and Raman spectra. Energy level structures of Tb3+, Bi3+ and Bi2+ ions were plotted for the excitation and energy transfer routes. The results show that Tb3+ doped Bi2O3-B2O3 glasses consist of [BO3], [BiO3], [BO4],and [BiO6] together as basic structural groups, and its structure turn looses as the optical basicity increasing from 0.63 to 0.93. Based on energy matching condition, 571 nm emission ascribed to 2P3/2(2)→2P1/2 transition of Bi2+ reduces from Bi3+ ions at high optical basicity of glasses, which decreases the transition of Bi3+→Tb3+. The luminescent properties of Tb3+ doped Bi2O3-B2O3 glasses are quite sensitive to optical basicity, the luminescence color turns to white from yellow-green with the optical basicity increasing.关键词：optical basicity;quenching;photoluminescence;energy transfer;Bi2O3-B2O3138|180|4更新时间：2020-08-12
- 摘要：Tb3+ doped borate, silicate and phosphate glasses and glass matrixes were prepared by high temperature melting technology. According to the UV-Vis transmission spectra, the experiment oscillator strengths of Tb3+ from 7F6 to 5D3 and 5D4 were calculated, and the luminescent properties of Tb3+ in different glass matrixes were explained. The results show that the 542 nm and 585 nm emissions of Tb3+ doped in phosphate glass have split into two peaks because of the poor symmetry. In borate and silicate glasses, the particles in 5D3 energy level of Tb3+ have been emptied and moved to 5D3 energy level because of the cross relaxation, so the emissions from 5D3 energy level (413, 436 nm) are not obvious. In phosphate glass, 5D3 energy level of Tb3+ has much fewer particles and no cross relaxation, so the emission from 5D3 energy level is the strongest. The characteristic emission peaks of Tb3+ from 5D4 energy level are 489, 542, 585 and 620 nm. In different glass matrixes, the order of their intensities from largest to smallest is borate, silicate and phosphate glass, which is consistent with the order of experiment oscillator strengths from 7F6 to 5D4.关键词：glass matrix;Tb3+;luminescence glass;oscillator strength127|125|1更新时间：2020-08-12
- 摘要：Sr0.97Si2N2O2:0.03Eu2+ phosphors were prepared by conventional high temperature solid-state reaction using Si3N4, SrCO3, and Eu2O3 as the raw materials. Excited by near-ultraviolet, the phosphors emit bright yellowish-green light and the peak of the emission spectra is at 533 nm. The crystalline phase formations of the phosphors with different fluxes(NH4F, NH4Cl, Li2CO3, H3BO3) were analyzed by X-ray diffraction (XRD). The effects of the fluxes on the morphology and luminescent properties of the phosphors were also investigated by scanning electron microscope (SEM) and fluorescence spectrometer, respectively. With the introduction of the fluxes, the agglomeration of the phosphors is relieved significantly, the crystallinity is increased, and the emission intensity is enhanced. For all the fluxes, NH4Cl has the greatest effect on the emission intensity of the phosphors.关键词：flux;Sr0.97Si2N2O2：0.03Eu2+;emission peak;luminescent properties89|73|4更新时间：2020-08-12
- 摘要：Ytterbium(Ⅲ),erbium(Ⅲ) co-doped sodium yttrium fluoride (NaYF4:Yb3+,Er3+) powder were prepared by microemulsion method. CTAB(Cetyltrimethyl ammonium bromide), n-butyl alcohol, n-octane and water were selected as the microemulsion system. The influence of NaF/Y3+ ratio, reaction temperature, reaction time, pH value, aging time, and heat treatment on phase formation, luminous efficiency and the particle size were studied. The results indicate that α-NaYF4:Yb3+,Er3+ samples can be obtained at 140 ℃ for 24 h with the optimal pH=5~6, and β-NaYF4:Yb3+,Er3+ samples can be obtained at 160 ℃ for 60 h with the optimal pH=1~4. The particle sizes of α-NaYF4:Yb3+,Er3+ and β-NaYF4:Yb3+,Er3+ are 200 nm and 1 μm, respectively. Excited by 980 nm LD, the samples emit bright green light peaking at 521, 529, 541, 549 nm, and 541 nm is the strongest.关键词：up-conversion luminescence;microemulsion method;NaYF4：Yb3+;Er3+;cubic;hexagonal101|128|0更新时间：2020-08-12
- 摘要：Mercaptosuccinic acid capped CdSe quantum dots were prepared in aqueous solution by using SeO2 as selenium source and NaBH4 as reductant. Then, the CdSe quantum dots bentonite luminescent material was prepared by mixing the CdSe quantum dots solution and organic bentonite under stirring. The obtained sample was characterized by photoluminescence spectra, scanning electron microscopy and X-ray diffraction. The spectra analysis results disclosed that the illuminant color of quantum dots bentonite composites was similar to the corresponding quantum dots solution. The energy-dispersive X-ray spectra demonstrated that Cd and Se elements presented in the composites. X-ray diffraction measurements indicated that the (111), (220) and (331) diffraction peak of CdSe appeared in quantum dots bentonite composites, and the (001) diffraction peak at 2θ=4.3° in the raw bentonite. These results suggest that the preparation of CdSe quantum dots bentonite composites do not change the structures of quantum dots and bentonite.关键词：quantum dots;composite materials;optical properties;luminescence124|132|0更新时间：2020-08-12
- 摘要：A linear copolymer (P(MMA-co-TPY)) containing ligands was prepared by the copolymerizing terpyridine monomer and methyl methyl acrylic monomer. Then the copolymer reacted with IrⅢ-chloro-bridged intermediate reaction, a polymeric material (P(MMA-co-TPYIr)) containing cyclometalated iridium complex was eventually obtained. Ring metal iridium complexes containing polymer P(MMA-co-TPYIr). The material was characterized by Fourier transform infrared spectra (FTIR), its optical properties and oxygen sensor performance were studied by ultraviolet-visible spectrometer, fluorescence spectrometer. The results show that the cyclometalated iridium complex groups have been covalently connected to the polymer chain, the luminescence wavelength is 638 nm in solid state which belonging to pure red light emission, and the quantum efficiency of 0.035. The material shows good oxygen sensor performance especially in DMF, the luminous intensity ratio is 6 in pure nitrogen and pure oxygen atmosphere. Its oxygen detection limit could reach 0.34%.关键词：cyclometalated iridium complex;polymethylmethacrylate;terpyridine;oxygen sensor111|236|0更新时间：2020-08-12
- 摘要：Green up-conversion luminescence material CaF2:xYb3+,yEr3+ (x=0.1~0.8, y=0.01~0.08) nanoparticles were synthesized by the hydrothermal method. The crystal structure, morphology and up-conversion spectra of the samples were characterized using X-ray powder diffractometer, transmission electron microscope and fluorescence spectrophotometer with single-wavelength diode laser of 980 nm. The samples are cubic phase and spherical shape with an average size of 12 nm. The influence of Yb3+ and Er3+ concentration on the up-conversion luminescence of the CaF2:xYb3+,yEr3+ (x=0.1~0.8, y=0.01~0.08) nanoparticles were systematically investigated and discussed. It is found that the optimum mole fraction of the sensitizer Yb3+ is 20% and the activator Er3+ is 6%. At this point, the ratio of the green and red light intensity is the largest.关键词：hydrothermal;rare-earth ion;up-conversion luminescence;nanoparticle162|82|1更新时间：2020-08-12
- 摘要：Chalcogenide glass microspheres were fabricated by high temperature melting floating glass powder method. The glass composition was 0.9%Er2S3(mass fraction):75%GeS2-15%Ga2S3-10%CsI(mole fraction). A quartz fiber taper with a 2.31 μm waist diameter was drew at fuse and used to couple a 119 μm diameter chalcogenide microsphere with a 980 nm LD pumping source. Fluorescence spectra with apparent resonance peaks were observed near 1.54 μm(Er3+:4I13/2→4I15/2). The difference of microsphere and bulk glass fluorescent spectrum was analyzed and the locations and separations of those resonance peaks were calculated using the Mie scatter theory. It is found that the theoretical results match the experimental results well, and the minimum error is only 0.05%. At last, we discussed the relationship of pump power and microsphere fluorescent peak gap, and removed the influence of pump power having on fluorescent peak gap.关键词：Er3+ doped chalcogenide glass;microsphere;fiber taper coupling;morphology of resonance112|106|4更新时间：2020-08-12
- 摘要：The micro plates, nano wires, micro tetrapods and micro spheres of ZnO were fabricated on the internal surface of quartz boat and the surface of single crystal silicon by chemical vapor deposition method, and the corresponding gas sensors were made. The following testing results from scanning electron microscope, the gas sensor testing instrument were obtained. The as grown ZnO with nano/micro structures have a different size from 200 nm to 100 μm. The optimized working currents range of these sensors are 120 ~ 130 mA. The gas sensor fabricated by micro tetrapods of ZnO exhibits the best sensitivity property and the corresponding sensitivity is up to 127. The highest content of VO defect exists in micro tetrapods of ZnO. Combining the gas sensor testing with PL spectra results, we attribute the most important factor affecting the gas sensor property to the content of VO defect in these materials.关键词：ZnO;chemical vapor deposition;gas sensing property;defect content104|210|2更新时间：2020-08-12
- 摘要：The total dose irradiation experiments were conducted on commercial triodes and MOS transistors. The impacts of different radiation temperature on the radiation effect were compared when the other conditions were identical. For the same total dose, the base current and current gain of the triode, and the threshold voltage of the MOS transistor exist a big discrepancy according to the different radiation temperature. When the total dose is 100 krad(Si) and the radiation temperature is 25, 70, 100 ℃, the current gain reduction of the NPN triode is 71, 89, 113,and the threshold voltage degradation of the NMOS transistor is 3.53, 2.8, 2.82 V, respectively.关键词：total dose effect;MOS transistor;triode;different temperature irradiation105|389|2更新时间：2020-08-12
- 摘要：Poly(3-hexylthiophene) based organic field effect transistors with poly(vinyl alcohol) gate dielectrics were fabricated by solution process. The effects of PVA gate dielectrics concentration on the performance of the devices were investigated. The experimental results show that the device with PVA mass fraction of 8% displays the best performance, which the field-effect mobility is up to 0.31 cm2·V-1·s-1 and the threshold voltage is as low as -6 V. Furthermore, the reason for the performance improvement of the devices was analyzed. It indicates that the appropriate PVA concentration is extremely important for the solution-processed OFETs.关键词：organic field effect transistors;gate dielectrics;concentration;PVA;P3HT107|108|0更新时间：2020-08-12
- 摘要：Two kinds of atmospheric argon plasma jet were generated by hollow needle to plate discharge. The velocity of discharge propagation was measured by two photomultipliers (PMT) and the length of the discharge was recorded by an ICCD camera. It was found that the velocity and the length were different during different voltage phase. In the positive discharge, the length and the velocity were 0.8 cm and (3.1±0.2)×106 cm/s, respectively. While in the negative discharge, they were 1.6 cm and (2.2±0.1)×107 cm/s, respectively. However, the two discharges propagated along the same direction. Moreover, the distribution of excitation temperature was obtained. The results show that the electric field plays an important role in propagating of plasma jet.关键词：discharge propagation velocity;electron excitation temperature;plasma jet;hollow-needle to plate discharge111|163|6更新时间：2020-08-12
- 摘要：We present a simple efficient green phosphorescent device based on the direct charge-recombination mechanism in heavy doping Ir(ppy)3. The 4,4',4"-Tris(carbazol-9-yl)triphenylamine (TCTA) and bis (4,6-difluorophenyl-pyridine)(picolinate) iridium(Ⅲ) (FIrpic) are selected as doping materials that doped into emitting layer respectively. The maximum current efficiency values of 43.1 cd/A and 51 cd/A are demonstrated in these devices, which increased by 50% and 79%, respectively. The results reveal a practical way to fabricate highly efficient bilayer organic devices.关键词：Ir(PPY)3;direct charge-recombination;hole-transfer;OLED110|228|2更新时间：2020-08-12
- 摘要：Graphene is an ideal material for the preparation of high performance conductive film because of its unique electrical properties, excellent mechanical ductility and good chemical stability. This paper presents the preparation of a double-layered graphene/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) conductive film, in which the PEDOT:PSS film was fabricated by using spray-coating technique. The surface morphology, optical and electrical properties of the double-layered conductive films were investigated. PEDOT:PSS can not only reduce the surface resistance of the graphene films, but also smooth the film surface. Flexible organic light-emitting diodes based on the double-layered film were fabricated, and the current efficiency increased with the voltage and reached its maximum of 0.9 cd/A when the voltage was 12 V. The device luminance did not show obvious degradation after 100 times bending with a radius of curvature of 10 mm. The hybrid films hold promise for the practical application of FOLEDs.关键词：graphene;PEDOT：PSS;spray-coating;FOLEDs168|107|9更新时间：2020-08-12
- 摘要：Using the plane wave expansion method, the band structure of two-dimensional photonic crystal was calculated under E polarization and H polarization. The influence of Ge-based tetragonal lattice photonic crystal filling ratio and the lattice structure on the maximum photonic band gap were analyzed. When Ge cylinders are placed in the air background, the TE band and TM band generate and the maximum complete band gap appears in the range of r/a=0.19~0.47, the maximum photonic band gap width can reach 0.064(normalized frequency). When air holes are placed in the Ge background, the TE and TM band also generate, and the maximum complete band gap appears in the range of r/a=0.46~0.49, the maximum photonic band gap width can reach 0.051(normalized frequency). Meanwhile, in both of the cylinder and air holes structure, along with the rising of r/a, the band gap width increases at first, and then decreases.关键词：plane wave expansion;TE mode;TM mode;complete band gap93|138|3更新时间：2020-08-12
- 摘要：The nonlinear refractive index and nonlinear coefficient of the fiber can be enhanced by doping GeO2 into the fiber core. A special photonic crystal fiber for generating optical solitons is designed via the finite element method. Its bandwidth is 1.45 μm around the anomalous dispersion regime. The optical solitons with any wavelength can be generated easily in this fiber at low pump power. The numerical results show that the highest average pump power used to obtain the fundamental soliton is 0.001 695 W when the pump pulse width TFWHM is 300 fs, and it is only 0.042 38 W used to obtain the fifth-order solitons.关键词：nonlinear optics;optics soliton;finite element method;various wavelength;low pump power105|207|0更新时间：2020-08-12
- 摘要：In order to eliminate the Moiré phenomenon in LED display screen of digital camera, the mechanism and the characteristics of Moiré phenomenon were analyzed. A method of eliminating the Moiré phenomenon of high-density LED display screen which uses multiple optical scattering films was proposed. The Moiré phenomenon elimination device was simulated by using optical simulation program. Moreover, the key parameters of the Moiré phenomenon elimination device were optimized. A verification experimentation was demonstrated on a P2.5 mm high-density LED display screen sample box using the optimized Moiré phenomenon elimination device. The experimental results coincided with the theoretical analysis. The optimized device can greatly reduce the contrast of the Moiré phenomenon of LED display screen. Therefore, it can be proved that the method we proposed to eliminate the Moiré phenomenon of high-density LED display screen is effective.93|166|1更新时间：2020-08-12
- 摘要：Based on the catalyzed oxidation of horseradish peroxidase (HRP) to the hydrogen peroxide and luminol system, a novel p-phenol derivative, 4-(1,2,4-triazol-1-yl)phenol (TP) was studied to enhance the chemiluminescence. With HRP labeled cardiac troponin Ⅰ (cTn Ⅰ) monoclonal antibody, a simple, sensitive, and rapid enzyme chemiluminescence immunoassay method enhanced by TP for the determination of cTn Ⅰ in human serum samples had been developed by "sandwich type" immune response.The experimental results show that there is a very good linear correlation between the enhanced enzymatic chemiluminescence intensity and the amount of cTn Ⅰ in the range of 1.2 ~ 24 ng/mL (R= 0.99), and the coefficient of variation (n=8) is 4.7%. The proposed enhanced enzymatic chemiluminescence immunoassay method had been used successfully for the determination of cTn Ⅰ in human serum.关键词：enzymatic chemiluminescence;enhancer;immunoassay;cardiac troponinⅠ108|120|2更新时间：2020-08-12
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