VO_2-WO_3复合薄膜的制备及其热致变色-电致变色性能研究

智能玻璃是目前建筑节能重点研究方向。本研究将自制氧化钒纳米粉体均匀分散到钨溶胶体系,取上清液旋涂于ITO基板,经干燥、退火后制得VO_2(M)-非晶WO_3复合薄膜。实验结果表明,所制备的VO_2(M)-非晶WO_3复合薄膜兼具热致变色和电致变色性能,通电后薄膜表现典型的电致变色特征,可见光和近红外光透过率明显下降。退火过程中,部分W掺杂到VO_2中,使薄膜的热致相变温度降低10°C左右。复合薄膜在双响应条件下,其可见光透过率为32.6%、调控效率为18.8%。     

Effects of NIR annealing on the characteristics of al-doped ZnO thin films prepared by RF sputtering

Aluminum-doped zinc oxide (AZO) thin films have been deposited on glass substrates by employing radio frequency (RF) sputtering method for transparent conducting oxide applications. For the RF sputtering process, a ZnO:Al₂O₃ (2 wt.%) target was employed. In this paper, the effects of near infrared ray (NIR) annealing technique on the structural, optical, and electrical properties of the AZO thin films have been researched. Experimental results showed that NIR annealing affected the microstructure, electrical resistance, and optical transmittance of the AZO thin films. X-ray diffraction analysis revealed that all films have a hexagonal wurtzite crystal structure with the preferentially c-axis oriented normal to the substrate surface. Optical transmittance spectra of the AZO thin films exhibited transmittance higher than about 80% within the visible wavelength region, and the optical direct bandgap (E_g) of the AZO films was increased with increasing the NIR energy efficiency.     

Synthesis of hydrophobic W18O49 nanorods for constructing UV/NIR-shielding and self-cleaning film

Nanomaterials with ultraviolet/near-infrared (UV/NIR) shielding property have great potential for developing energy-saving windows. In this work, we report low-cost W₁₈O₄₉ nanorods as UV/NIR shielding material. W₁₈O₄₉ nanorods with the length of ~20 or ~60 nm were prepared by simple solvothermal method, and they exhibited strong size-dependent absorption in the UV/NIR region. By mixing W₁₈O₄₉ nanorods with polydimethylsiloxane (PDMS), W₁₈O₄₉@PDMS films were constructed and they could shield 55.58% of UV and 75.89% of NIR light while transmit 58.03% of visible light. A sealed box with W₁₈O₄₉@PDMS-coated glass as the window exhibited a minimal temperature elevation (△T = 9.2 °C) compared to those coated with pure glass (△T = 18.2 °C) or ITO glass (△T = 12.1 °C), under the irradiation of solar light (0.6 W cm⁻²). Additionally, the films had a contact angle of 122 ± 2°, showing self-cleaning ability. Therefore, W₁₈O₄₉@PDMS films can act as cost-efficient UV/NIR-shielding and self-cleaning film.     

Substrate temperature-dependent physical properties of nanocrystalline zirconium titanate thin films

Nanocrystalline zirconium titanate thin films were deposited by direct current magnetron reactive sputtering on to glass substrates at room temperature and at different substrate temperatures of 423, 473, 523, and 573 K under high vacuum conditions. The deposited films have been characterized to study the physical properties of the films as a function of substrate temperature. Though the film exhibited amorphous characteristics at room temperature the higher temperatures resulted in the evolution of crystallites in the films. The crystallinity increased with temperature from 423 K onwards and the film deposited at 523 K exhibited a high crystallite size of 22 nm. The SEM images of the films revealed the improvement in the crystallinity from 423 to 523 K with dense columnar structure normal to the substrate. Further higher treatment deteriorated the film properties. The films showed a good transmittance of above 80%. A high optical transmittance of 91% and a high packing density of 96% have been observed for the film deposited at 523 K. The thickness of the films remained consistent at ~230 nm (±6 nm). It is noticed that an increase in the substrate temperature enhanced the structural, optical, and electrical properties of the films up to 523 K.     

Near-infrared-shielding energy-saving borosilicate glass-ceramic window materials based on doping of defective tantalum tungsten oxide (Ta0.3W0.7O2.85) nanocrystals

NIR-shielding window materials were fabricated by direct embedding of Ta_0.3W_0.7O_2.85 nanocrystals in bulk borosilicate glass-ceramics during a facile melt-quenching process. Optical and thermal performance of the prepared windows can be adjusted by varying the concentration of H₂WO₄ and Ta₂O₅ in the starting materials. The optimized window fabricated from raw materials containing 4.5 mol% H₂WO₄ and 0.3 mol% Ta₂O₅ exhibited high visible light transmittance 74.4% and strong NIR-shielding ability ΔT = 68.9%. Its thermal insulation performance is much better than soda lime glass or ITO glass, and its visible light transmission is higher than cesium-tungsten-bronze-based film coated glass. The distribution of Ta_0.3W_0.7O_2.85 functional nanocrystals in the glass matrix was confirmed by sample characterization using XRD, Raman, XPS, HRTEM and EDS. The NIR-shielding property has been attributed to local surface plasmon resonance due to oxygen vacancies in the Ta_0.3W_0.7O_2.85 nanocrystals. This study sheds a light on fabricating energy-saving windows with a tunable NIR-shielding performance.     

Development of anchored oligothiophenes on substrates for the application to the tunable transparent conductive films

Bis(triethoxysilyl)-substituted oligothiophene with a moderate π-conjugation length was newly synthesized and polymerized to give a polysilsesquioxane network having oligothiophene units dispersed homogeneously without phase separation. The polymer was fixed on glass or ITO substrate by spin-coating and annealing. The resulting film exhibited a high mechanical strength due to the covalent bonding with the substrates, and was electrochemically stable even after 300 redox cycles in electrolyte solution. Chemical oxidation of the polymer films yielded electrically conductive and almost transparent films.     

Greatly improved NIR shielding performance of CuS nanocrystals by gallium doping for energy efficient window

In this work, gallium doped copper sulfide (Ga-doped CuS) nanocrystals were prepared using a solvothermal method. The effects of Ga doping on the crystal structures, chemical composition, morphology, optical properties and thermal performance of copper sulfide (CuS) were investigated. The Ga-doped CuS nanocrystals had a hexagonal structure comparable to that of pure CuS. The Cu⁺/Cu²⁺ ratio first decreased and then increased with increasing Ga³⁺ doping. Both CuS and Ga-doped CuS exhibited nanoplate and nanorod morphologies. The visible transmittance of the Ga-doped CuS films was in the range of 61–77.1%. Importantly, the near-infrared (NIR) shielding performance of the films can be tuned by adjusting the concentration of the Ga dopant. The NIR shielding value of the optimal Ga-doped CuS film was 72.4%, which was approximately 1.5 times as high as that of the pure CuS film. This can be ascribed to the enhanced plasmonic NIR absorption that resulted from an increase in the hole concentration after doping with Ga³⁺ ions. In the thermal performance test, the Ga-doped CuS film lowered the interior temperature of the heat box by 9.1 °C. Therefore, the integration of good visible transmittance and high NIR shielding performance make the Ga-doped CuS nanocrystals a promising candidate for energy-efficient window coatings.     

Influence of Ag mid-layer in the optical and thermal properties of ZnO/Ag/ZnO thin films on the glass used in Buildings as insulating glass unit (IGU)

The low-emissivity (low-E) coatings are multiple ultra thin layers on glass used for producing spectrally selective glazing. The use of low-E glazing in building windows makes it possible limit the radiative heat transfer without reducing the visible transmittance perceptibly and accordingly alter the necessary natural lighting in low energy buildings. In this study, we investigate ZnO/Ag/ZnO thin films deposited on glass substrate via RF and DC sputtering by ZnO and Ag targets respectively, in various deposition time of Ag layer. We tried to diminish the NIR transmittance by using a feasible and affordable method with a low number of ultra thin layers and by reducing the cost of the vacuum.Presented results are related to electrical, optical and thermal properties for tri-layers based on sandwiched Ag by ZnO in deposition time of 10–45?s at room temperature.     

Preparation and characterization of PVC/CsxWO3 composite film with excellent near-infrared light shielding and high visible light transmission

Near-infrared (NIR) shielding is essential not only in the building and automobile glass films but also in achieving energy conservation. However, effectively shielding NIR and maintaining high transmittance in the visible light region have been great challenges in the past decade. Recently, hexagonal cesium tungsten bronze (Cs_xWO₃) nanoparticles have been widely studied due to the excellent transparency in the visible light region and strong heat-shielding ability in the NIR region. Herein, a design concept of transparent polyvinyl chloride (PVC)/Cs_xWO₃ composite film, as a heat insulation material for glasses, was proposed. To achieve this purpose, the PVC/Cs_xWO₃ composite film was prepared by incorporating Cs_xWO₃ slurry with better dispersion than traditional Cs_xWO₃ nanoparticles powder into a transparent PVC matrix. By the UV-Vis-NIR spectrophotometer characterization, the PVC/Cs_xWO₃ composite film containing 2.1 phr Cs_xWO₃ slurry displays high blocking of NIR (78%) and high transmittance of visible light (76%). In order to further understand the actual heat insulation effect from the PVC/Cs_xWO₃ composite films, the indoor sunlight simulation test and outdoor cooling experiment with solar illumination variations were carried out, which both showed heat insulation that is superior to the antimony tin oxide and indium tin oxide thin films prepared in our previous work. In addition, the mechanical property of PVC/Cs_xWO₃ composite films shows almost no change with the increase of Cs_xWO₃ slurry. The PVC/Cs_xWO₃ composite films simultaneously achieve excellent shielding of NIR and high transmittance of visible light, which makes it an ideal material to alleviate the current building energy consumption issues.     

Extracting the Optical Parameters of the Fabricated (Al/Bare Borosilicate Crown Glass,BK-7/Ag) Multiple Layers

Significant effort has been devoted in this work to convert bare glass substrate with high transmittance, into reflective layers to know its suitability for modern applications. The glass substrate has been carefully chosen for its durability, high permeability, and ability to withstand any external stresses as a result of the accumulation of layers that reduce its permeability to convert it with the thin films coated on it into reflective materials. In parallel, the thin layer to be coated on the substrate is selected from films that can withstand external influences and their great optical properties, not to mention that they are cheap and can produce highly reflective surfaces. The optical measurements (transmittance and reflectance spectra) have been performed in the UV, Vis and NIR regions of the spectrum, that is, in the range between 300 and 1200 nm. Such measurements have been made for the bare glass substrate, the glass substrate with the Al (top side), and the glass substrate with Ag on it (bottom side), and then the optical measurements have been made for the three layers. The corresponding optical parameters of each layer have been calculated and ultimately a reflective layer with high electrical conductivity and excellent optical properties has been obtained that can be adapted for different application purposes.

     

Controlled thin layer coating of carbon nanotube-polymer composites for UV-visible light protection

A highly dispersed solution of multi-wall carbon nanotubes (MWCNT) and counterpart polymers was prepared in aqueous solution. A thin layer coating was deposited on glass substrates by using the layer-by-layer (LBL) method. A negative charged dispersion solution of MWCNT was obtained by oxidizing the MWCNT by immersion in nitric acid. Counterpart polymers, poly(diallydimethylammonium chloride) (PDDA) and poly(acrylic acid) (PAA), were used as base materials. The zeta potential measurements of the MWCNT solution showed the strongest potential at pH 4 and strong polyanionic surfaces at pH 5. A home-made automatic LBL machine was used to coat the polycationic/anionic materials on glass substrates. The substrate was coated homogeneously by the LBL method and the transmittance from the range of ultraviolet (UV) to visible light was manipulated in the coating process. This simple technique might be effectively utilized for fabrication of micro-sensing and energy harvesting devices, and UV light protection.     

Effect of oxygen flow ratio on crystallization and structural characteristics of gallium oxide thin films

Beta-gallium oxide (β-Ga₂O₃) thin films were prepared on a MgO (100) substrate under different oxygen flow ratios via magnetron sputtering. X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and UV–visible near-infrared (UV–vis–NIR) analyses were conducted to study how the oxygen flow ratio affected the crystalline quality and the surface topography of the films. Microstructure analysis revealed a clear out-of-plane orientation of β-Ga₂O₃ (100) || MgO (100). The film deposited under an oxygen flow ratio of 1% presented the optimal single-crystalline structure, while excess oxygen was confirmed to negatively impact the crystallization characteristics of the films. SEM measurements indicated that the increase in the oxygen flow ratio reduced the grain size and RMS roughness. The average transmittance of the β-Ga₂O₃ films in the visible range exceeded 83%, with a broad luminescence band exhibited at approximately 485 nm in the photoluminescence (PL) spectra.     

热处理温度对铁镍合金膜层微观结构和镀膜玻璃性能的影响

为了研究不同热处理温度下铁镍合金薄膜的形貌结构以及镀膜玻璃的性能,本文采用真空电子束加热蒸发镀膜技术在玻璃基片上镀铁镍合金薄膜,通过多晶X射线衍射(XRD)和场发射扫描电子显微镜(FESEM)分析结构,测试镀膜玻璃的光学性能、电磁性能以及电磁屏蔽性能。结果表明:随着热处理温度的升高,薄膜的结晶性能变好,逐渐析出体心立方晶相,在(110)方向具有择优取向,当热处理温度过高时薄膜中出现孔隙;热处理温度对镀膜玻璃雾度的影响小于1%,但镀膜玻璃的可见光透过率、表面方块电阻和相对磁导率会随热处理温度变化呈现一定规律变化;铁镍合金镀膜玻璃在30 MHz以下的低频电磁波频段内的屏蔽效能大于30 dB,在14 kHz时最高达到55 dB,是一种低频电磁屏蔽的优选材料。     

Enhanced conductance properties of UV laser/RTA annealed Al-doped ZnO thin films

Thin films comprising 0.5 mol% aluminum-doped zinc oxide (AZO) were prepared on glass substrates by a spin-coating method for transparent conducting oxide (TCO) applications. UV laser was selected for the annealing of AZO thin films, due to the well matched energy bandgap between UV laser and AZO films. After the rapid thermal annealing (RTA) process, post UV laser annealing was carried out by varying the scan speed of the laser beam, and the effects of laser annealing on the structural, morphological, electrical, and optical properties were analyzed. The results indicated that UV laser annealing based on various scan speeds affects the microstructure, sheet resistance, and optical transmittance of the AZO thin films, compared with those of the only RTA processed thin films. X-ray diffraction (XRD) analysis showed that all films that preferentially grew normally on the substrate had a (002) peak. The optical transmittance spectra of the laser/RTA annealed AZO thin films exhibited greater than 83% transmittance in the visible region. Also, the sheet resistance (1.61 kΩ/sq) indicated that optimized UV laser annealing after the RTA process improves film conductance.     

Electrochemical study of TEOS,TEOS/MPTS,MPTS/MMA and TEOS/MPTS/MMA films on tin coated steel in 3.5% NaCl solution

This work compares the anticorrosion features of siloxane layers as eco-friendly alternatives for chromium passivation process on industrials tin coated steel and unravels the influence of each component of the film. The films were prepared with synergistic blends of siloxanes as tetraethyl orthosilane (TEOS), 3-methacryloxy-propyl-trimethoxysilane (MPTS) and methyl methacrylate (MMA). To assess the influence of each component, five different films were prepared: TEOS-based, MPTS-based, TEOS/MPTS, MPTS/MMA and TEOS/MPTS/MMA. The corrosion resistance of the coatings was evaluated by means of open circuit potential, anodic polarization curves and electrochemical impedance spectroscopy measurements, and the anticorrosion properties discussed based on electrical equivalent circuit fitting. Coated surfaces were analyzed using atomic force microscopy and the coatings’ thicknesses were evaluated by means of glow discharge optical emission spectroscopy. The results plainly showed the efficiency of the anticorrosion properties of the film in a 3.5 wt.% NaCl solution and have clearly revealed the improvement of the protective properties of the coating when the MPTS was added to the formulations, pointing this component as the main responsible for the coating anticorrosion action. The addition of MMA to the formulation led to formation of coatings with low long term anticorrosion protection, which was ascribed to the low thickness.     

Deposition and characterization of AZO thin films on flexible glass substrates using DC magnetron sputtering technique

Al-doped zinc oxide (AZO) thin films were deposited onto flexible ultra-thin glass substrates by using a direct current (DC) magnetron sputtering process. The effects of sputtering power, working pressure and substrate temperature on the morphology and optoelectronic performances of AZO films were investigated. The optimal sputtering power, working pressure and substrate temperature for AZO film were determined to be 100 W, 0.9 Pa and 150 ℃, respectively. Further increasing or decreasing the sputtering power, working pressure and substrate temperature degrades the quality of AZO films. XRD patterns show all as-sputtered AZO thin films are preferred to grow along <0002> direction. Moreover, the largest grain size, which depicts the best microstructure of AZO films, matches with the smallest stress value. It can be seen from SEM images that the surface is smooth and dense. The smallest value of the resistivity is 1.784×10⁻³ Ω cm and the average transmittance of all AZO films in the visible range is about 80%. The X-ray photoelectron spectroscopy spectra show that the amount of Al element in the AZO film is very small.     

Preparation and characterization of UV‐curable organic/inorganic hybrid composites for NIR cutoff and antistatic coatings

In this study, UV‐curable organic/inorganic hybrid composite coatings with near infrared (NIR) cutoff and antistatic properties were prepared by high‐shear mixing of two kinds of polymer matrices and coated on plastic and glass substrates by the doctor‐blade method. This study also investigated the morphology, stability, optical properties, electrical resistivity, and durability of the UV‐cured composite coats. It was found that the composite coatings were very stable under centrifugation. Moreover, the films with transmittance of above 80% in a visible light region (400–800 nm) and of ～ 40% to 50% in the NIR region (1000–1600 nm) showed low haze of 6.9%, electrical resistivity of around 2.3 × 10⁷ Ω/square. Thus, excellent adhesion, scratch, and weathering durability can be produced on polycarbonate substrate at room temperature. The experimental results reveal that UV‐curable organic/inorganic hybrid composites can be used effectively to fabricate films with NIR cutoff as well as antistatic properties, indicating a high potential for practical application in architectural, automotives, and optoelectronics. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation of epoxy-silica-acrylate hybrid coatings

Summary An organic-inorganic epoxy-silica-acrylate hybrid coating had been prepared by radical solution copolymerization and sol-gel process. The room curing reaction of the hybrid coating was discussed, and its structure, optical properties and thermal stability were studied. The hybrid coatings have multiple functional groups, and the inorganic phase and organic phase are linked by the chemical bonding. When tetraethylorthosilicate (TEOS) mass fraction were 10% and 20%, hybrid coatings had inorganic particle mean sizes of 36 nm and 45 nm, respectively, together with their homogeneously distribution within the polymeric matrix. With increasing of TEOS content, the transmittance in the visible region and the yellow index (YI) of the hybrid coatings after UV irradiation decrease, while the absorbency at 300–400 nm, the onset decomposition temperature and maximum weight loss temperature increase.     

Effect of substrate temperature on the properties of TiO2 nanoceramic films

TiO₂ nanoceramic films were deposited on glasses by rf magnetron sputtering. This method provides more advantages in controlling the microstructure and composition of the films. TiO preferentially formed and the deposited films tended to become nonstoichiometric by increasing substrate temperature. The morphologies and hydrophilic properties of TiO₂ films were significantly affected by the substrate temperature. The nonlinear refractive index of the TiO₂ film on the glass substrate measured by Moiré deflectometry was of the order of 10^?8 cm² W^?1. Smaller grain size, higher optical energy gap, visible transmission and linear refractive index, and lower stress-optical coefficient were obtained at lower substrate temperature.     

硅铝溶胶改性甲基硅树脂耐划伤薄膜

以甲基三甲氧基硅烷(MTMS)的水解缩聚产物作为主要成膜物质,正硅酸乙酯(TEOS)水解缩聚产物硅溶胶及异丙醇铝制备的勃姆石溶胶作为无机增强物,通过共缩聚反应在聚碳酸酯(PC)板表面制备硅铝胶改性甲基硅树脂耐磨薄膜;采用TG/DTA、FTIR、UV-VIS、金相显微镜及铅笔硬度测试方法对薄膜的结构及性能进行表征。研究结果表明,甲基硅树脂、硅胶、铝胶通过共缩聚反应在PC板表面形成带有机基团的无机交联网络结构,基本骨架由Si-O-Si,Si-O-Al,Al-O-Al组成;添加铝胶后,提高了薄膜的耐热性能以及薄膜硬度;薄膜对PC片的可见光透过率有一定的增透作用;铝胶的掺杂使薄膜表面不平整。