Advanced Materials Research Vols. 750-752

Abstract: A novel nonlinear optical active triazine dye 2-(4-methyl-4-amino-azobenzene )-4-sodium sulfanilate-6-chloro-1,3,5-triazine was synthesized by condensation reaction and characterized by FTIR, ¹HNMR, respectively. Their nonlinear optical properties were investigated using 5 ns pulse at 532 nm, which showed excellent nonlinear optical property.

Abstract: It can increase the utilization rate of light energy and improve the reflection properties of materials by adding order of micro lens array on the material surface microstructure. The models to predict the change of material reflection properties with microstructure radius, height and arrangement was been established based on the optical design software Light Tools. By adding high refractive index TiO₂ into the diffuse material with microstructure, the reflection properties of materials can been improved again. The results of the diffuse material molding test showed that the microstructure and its composite material had good reflection performance, reflection and diffuse reflection ratio could reach 93% and 93%, and the illumination uniformity could reach 63%.

Abstract: The graphite intercalation compound with large exfoliated volume was prepared by chemical oxidation method. The experimental parameters on the exfoliated volume were discussed in detail. It was found that the optimum preparing conditions went as follows: the mass ratio of graphite flakes:C₂H₅COOH:FeCl₃:CrO₃=1:2.8:0.3:0.2, the reaction temperature and time were 30 °C and 40 minutes, respectively. The exfoliated volume of GIC reached up to 575 mL·g¹ in the conditions. The composition, structure and properties of the graphite intercalation compound were characterized and analyzed by SEM, TG, DSC, VSM techniques. The millimeter wave (MMW) attenuation performances of GIC were investigated by MMW radar measurement device. The results showed that the MMW attenuation properties of FeCl₃-GIC are batter than H₂SO₄-GIC because of its magnetic absorption for millimeter wave.

Abstract: The 40ZnO-30SiO₂-20B₂O₃-10Na₂O:Sm³⁺ glass was prepared by high-temperature melting method. The structure and composition of the glass matrix was investigated by Infrared spectrum (IR). The absorption, excitation and emission spectra of the samples were tested, and the results showed that the glass can emit orange shade under light excitation. The emission peaks at 565nm, 604nm and 650nm wavelength were corresponding to the ⁴G_5/2⁶H_5/2, ⁴G_5/2⁶H_7/2 and ⁴G_5/2⁶H_9/2 transition emission of Sm³⁺, while the ⁴G_5/2⁶H_7/2 transition emission was the strongest. So the best Sm³⁺-doping molar concentration was 0.4%. The spectroscopic properties indicated that 40ZnO-30SiO₂-20B₂O₃-10Na₂O: Sm³⁺ was expected to become a new conversion material.

Abstract: The magnetic phase transition and magnetic entropy change of melt-spun LaFe_11.6Si_1.4B_x (x=0.0, 0.3, 0.5, 0.7) ribbons were investigated by measuring the magnetization as the function of temperature. Comparing with LaFe_11.6Si_1.4, the NaZn₁₃-type structure of LaFe_11.6Si_1.4B_x did not change after introducing B atoms, while the amount of α-Fe phase in the ribbons significantly decreased. The Curie temperature slightly changes after the addition of B. The LaFe_11.6Si_1.4B_x (x=0.3, 0.5) exhibits first-order magnetic transition and large magnetic entropy change as observed in LaFe_11.6Si_1.4 compound.

Abstract: Four types of graphene nanosheets (GNs) with different graphene layer number were employed to fabricate counter electrode for dyesensitized solar cells (DSCs), with emphasis on understanding the influence of graphene layer number on the properties of the counter electrode and the device. The results show that with the graphene layer number of the GNs increases from 3 to 8, both efficiency and fill factor of the GNs based DSCs firstly climb and reach a peak at 6 of graphene layer number, and then decline with further increasing. Electrochemical impedance spectroscopy (EIS) reveals that when the graphene layer number of the GNs increases from 3 to 6, the decreased sheet resistance of the electrode and the strengthened capability of electrolyte diffusion in the electrode result in the improvement of the photovoltaic performances of the DSCs. However, when the graphene layer number further ascends to 8, the weakened capabilities of both catalytic activity of the electrode for the reduction and electrolyte diffusion in the electrode lead to the poor photovoltaic performances of the device.

Abstract: Temperature dependence of photoluminescence (PL) and time resolved photoluminescence (TRPL) were obtained by two experimental systems. The relative intensity and peak position of PL show S-shift variation with increasing temperature, which may result from temperature induce carriers redistribution. Fast decay time and slow decay time were fitted by double exponential function from decay curves of TRPL at different emission energy, and the decreasing trend of both fast decay and slow decay time with increasing photon energy is attributed to various channels of recombination in shallow and deep localized states.

Abstract: La-doped (Bi_1-xLa_x)₂Ti₂O₇ (BLTO) thin films with different La contents have been grown by CSD method. All the XRD patterns of the samples showed that the films were polycrystalline films. The intensities of the peaks decreased with the increasing of La contents. The general trend of the changes of leakage current was decreased with the increasing of x. The case of dielectric constant as a function of La content is complicated. The rule of change of the dielectric constant is different with different la contents. In view of dielectric constant and dielectric loss, we think that the film of x=0.2 has relative low leakage current and high dielectric constant, which is considered to be adequate for a DRAM.

Abstract: The energy band structure of InAs/GaSb superlattice can be tailored by changing the thickness of InAs or GaSb layer thickness. Different superlattice as InAs/GaSb (4ML/8ML, 8ML/8ML and 16ML/7ML) for cut-off wavelengths from short to long IR wavelength were designed and deposited on GaSb substrates by melocular beam epitaxy system. The lattice mismatch was below 1000ppm under the careful Ga_1-xIn_x- type interface control. The responsitivity revealed the band structure in InAs/GaSb superlattice can be tailored and the cutoff wavelength was from 2.5μm to 11μm. The current-voltage relation and the differential resistance in infrared photodiode were also measured and studied.

Abstract: The magneto-optical Kerr effect (MOKE) for both Heusler type alloys (AuMnSb and AuMnSn) were studied using the full-potential linearized augmented plane-wave (FP-LAPW) method, based on the density functional theory implemented in the WIEN2k code. The differences with previous calculations on the Kerr spectra have been found explicitly. At proper Lorentzian such as δ = 0.4 eV, the calculated Kerr angle of AuMnSn reaches its maxima +0.3° near 0.6 eV and-0.5° at 5.2 eV, respectively while the MOKE spectra of AuMnSb exhibit less prominent Peaks (+0.5° at 0.3 eV, -1.9° at 0.9 eV, -1.0° at 2.4 eV and-2.0° at 5.3 eV). The results on the spectra in this work showed quite a lot differences with all previous all-electron calculations. It is concluded that the contribution from Sb (or Sn) site to the magneto-optical kerr effect is quite crucial in Heuslar alloys.