全固态电致变色器件工艺技术研究

提出一种新型结构与材料的全固态电致变色器件,及其氢化技术和制作工艺。在实验室中研制出2cm×2cm可重复转换、性能优良的电致变色器件,为大面积电致变色器件连续自动生产线的研制作了必要的技术准备。     

Anhydrous proton conductivity of acid doped vinyltriazole-based polymers

Poly(1,2,4-vinyltriazole) (PVTr) and poly(1,2,4-vinyltriazole-co-5-vinyltetrazole-co-acrylonitrile) (P(VTr-VT-AN)) were prepared by normal free radical polymerization and click chemistry, respectively. The structure of the polymers was characterized by FTIR spectra, H NMR spectrum and elemental analysis. Compared with polybenzimidazole (PBI) which is one of the most widely studied anhydrous proton conducting polymers, the solubility of vinyltriazole-based polymers is improved significantly. They are soluble in a lot of polar solvents. The glass-transition temperatures of such kind of polymers are between 70 and 85 °C, thus indirectly indicating the improvement of fabricating properties. In phosphoric acid doped membranes, the higher the basicity of the vinyltriazole-based polymers is, the higher the proton conductivity is. The temperature dependence of the proton conductivity of the acid doped membranes can always be fitted by a simple Arrhenius equation. Transmittance of phosphoric acid doped vinyltriazole-based polymers is above 80% in the range of visual spectra and changes a little with the different structure and basicity of the copolymers.     

A Novel Bandpass Filter Made of the Microstrip with Cantor Substrates

In this paper, the microstrip line with fractal Cantor distributing substrates is investigated. Transmission matrix method is used to calculate the transmittance and reflectance. Comparing with periodic distributing substrates, the microstrip line with fractal Cantor distribution shows sharp resonances inside band gap. The resonances in somewhere split and form more peaks with increase of the number of generation. Based on the microstrip line with Cantor substrates, a novel bandpass filter is proposed. The filter has 8.8 % 3dB bandwidth and two transmission zeros, 0.27dB insertion loss. The effect of width of microstrip line and thickness of substrate on the filter properties are discussed too.     

Hybrid ZnO NR/graphene structures as advanced optoelectronic devices with high transmittance

A hybrid structure (HS) made of one-dimensional ZnO nanorods (NRs) and a two-dimensional synthesized graphene sheet was successfully constructed in this study. The uniform ZnO NRs were obtained by hydrothermal method and grown on a graphene surface that had been transferred to a polyethylene terephthalate substrate. The HS exhibited high transmittance (approximately 75%) over the visible wavelength range, even after cyclic bending with a small radius of curvature. Raman spectroscopy and Hall measurement were carried out to verify the chemical composition and electrical properties of the structure. Stable electrical conductance of the ZnO NR/graphene HS was achieved, and increase in carrier mobility decreased the resistance of the ZnO-with-graphene sheet in comparison with bare ZnO NRs.     

Effect of yttrium solubility on the structural and optical properties of Bi1.5−xYxZn0.92Nb1.5O6.92 pyrochlore ceramics

In this article, the yttrium solubility effects on the structural, dielectric and optical properties of the Bi_1.5?xY_xZn_0.92Nb_1.5O_6.92 (Y–BZN) solid solutions are investigated. The yttrium content (x) was varied in the range of 0.04–0.6. The scanning electron microscopy and energy dispersion analysis have shown that the single phase of the yttrium doped pyrochlore is possible up to yttrium content of 0.06. At x=0.07 YNbO₄ minor phase appears and at x=0.08 YNbO₄ and ZnO dominates in the Y–BZN. Due to the very rare amount and the random distribution of the minor phases in the pyrochlore, the X-ray diffraction technique was not able to detect these minor phases at low yttrium doping levels. While the nonstoichiometric phase evaluated at x=0.07 displayed no role on the relative density, the dielectric constant, dielectric loss, the temperature coefficient of dielectric constant, the absorbance and the energy band gap are observed to be sharply altered. The energy band gap of the pure BZN widened from 3.30 eV to 3.60 eV when the BZN was doped with Y content of 0.04. It then sharply shrunk to 2.75 eV for Y content of 0.07.     

Joining transparent spinel ceramics using refractive index–matched glass

Ceramic joining by glass is a promising method of the preparation of large transparent ceramics from small blocks. The chemical composition of glass was optimised to match the coefficient of thermal expansion and refractive index of transparent magnesium aluminate (MgAl₂O₄) ceramics. A two-step joining method was developed to join MgAl₂O₄ ceramics with a reduced number of bubbles in the joint, and the thermal properties of the optimised glass were evaluated to determine the joining temperature. Two transparent MgAl₂O₄ blocks were joined by a glass layer that was approximately 20 µm thick. The joint area could not be distinguished with a naked eye. The transmittance of the joined body vertical to or parallel through the glass layer was approximately the same as that of the ceramics. The average three-point bending strength of the joint reached 202 ± 33 MPa, which was 64% that of the ceramic body.     

Lightwave irradiation-assisted low-temperature solution synthesis of indium-tin-oxide transparent conductive films

Transparent conductive oxide (TCO) films have important applications in many areas. Unfortunately, TCOs are usually fabricated using vacuum and high-temperature methods, preventing them from applications in low-cost flexible devices. In this paper, facile low-temperature sol-gel method is described that can be used to fabricate high-quality TCO films. This study uses lightwave (LW) irradiation (at ～280 °C) with indium-tin-oxide (ITO) as a typical example. Both structure and key properties of ITO films are investigated for different LW irradiation conditions. ITO can be formed via LW irradiation after a period as short as 5 min. Furthermore, it is found that LW irradiation can promote the formation of M ? O framework, effectively remove Cl impurities, and facilitate the elimination of hydroxyl oxygen defects - even at temperatures as low as ～280 °C. The optimal ITO films show excellent electronic properties, including low sheet-resistance (14.5 Ω·sq^?1) and high conductivity (1.7 × 10³ S cm^?1). Moreover, ITO films also show high transmittance (above 87%). Overall, our ITO films have a figure of merit (FOM) of 1.72 × 10^?2 Ω^?1, which is comparable to (or higher than) those of previous ITO films that were produced using conventional vacuum and high-temperature methods. Our LW irradiation method provides facile and effective approach to produce high-performance TCO films at remarkably low cost. This means these films could be used in affordable flexible large-area devices.     

THz激光F-P片旋转透过率研究

在不同角度下测量THz激光透过率对于材料性质研究及THz参数测量具有重要意义。本文在实验上研究了旋转F-P片的THz激光透过率,分别在不同角度下测量了硅片和锗片的THz激光透过率,测量角度范围0.175-2.967 rad,旋转步长0.175rad,得到的THz激光透过率具有一定的周期性,实验验证了旋转F-P片测量THz激光透过率在测量THz激光波长等应用的可行性。     

Vacuum sintering of highly transparent La1.28Yb1.28Zr2O7.84 ceramic using nanosized raw powders

Highly transparent La_1.28Yb_1.28Zr₂O_7.84 ceramic was prepared by vacuum sintering using nanosized raw powders, which were synthesized by a simple solution combustion method using rare earth nitrate as the raw materials. The as-burnt powders were calcined at 1200?℃ and then ball-milled for 24?h with resultant particle size of about 60?nm. The two phases, cubic pyrochlore and defective fluorite, are uniformly distributed in the ceramic. La_1.28Yb_1.28Zr₂O_7.84 transparent ceramic with the maximum in-line transmittance of 83.9% was successfully prepared at 1850?℃ for 6?h in a vacuum furnace.     

The effects of whitening and dust accumulation on the microclimate and canopy behaviour of rose plants (Rosa hybrida) in a greenhouse in Zimbabwe

The effects of whitening and of dust accumulation on the optical properties of materials in use as greenhouse covers in Zimbabwe were investigated. The effect of whitening was investigated in a greenhouse by measuring the transmittances for total solar, photosynthetically active radiation (PAR) and thermal radiation before and after painting the cover with lime-based whitewash paint, as used for shading in Zimbabwe. In addition, to evaluate the effect of dust, the transmittances for total solar, PAR and thermal radiation of a plastic sample were measured when dirty, due to exposure to the environment for 6 months, and again after cleaning. Whitening reduced the transmission coefficients for PAR, total solar and thermal radiation of the greenhouse cover from 0.75 to 0.53; 0.74 to 0.55 and 0.45 to 0.43, respectively. Dust and dirt accumulation due to 6 months exposure to the environment reduced the transmittances for all wavebands of the plastic sample (relative to their initial values) by 16%, 15% and 13%, respectively. To investigate the effect of these changes in the optical properties on greenhouse microclimate and canopy behaviour, the measured changes in transmittances were used in the Gembloux Dynamic Greenhouse Climate Model (GDGCM). The model showed that whitening of the greenhouse roof led to significant reductions in the maximum air temperature, vapour pressure deficit, canopy-to-air temperature difference and transpiration rate, while the canopy stomatal resistance was not significantly affected. These reductions, together with a decrease in the crop water stress index, indicate that the crop was less stressed after whitening. The model showed similar, but smaller, changes to all the microclimate and canopy parameters due to the accumulation of dust on the greenhouse roof.