Papers by Keyword: Transmittance

Abstract: In this paper, ZnO thin films were prepared on ITO conductive glass by direct current magnetron sputtering and the Cu electrodes were evaporated on ZnO/ITO by electric beam evaporation to get transparent Cu/ZnO/ITO resistive random access memory. The crystal structure and surface morphology were investigated by X-ray diffraction and atomic force microscopy, respectively. The transmittance spectra of ZnO/ITO in the visible region were measured by UV-VIS spectroscopy. The resistive switching characteristics of the fabricated devices were investigated by the voltage sweeping method, which showed that the transparent Cu/ZnO/ITO device had good resistive switching characteristics.

Abstract: When installing concentrator photovoltaic (CPV) systems in desert areas, we must consider the impact of sandstorms on the Fresnel lens in CPV modules. CPV systems are much more sensitive to sandstorms than flat-panel PV systems because they can only use the direct beam component of sunlight. In this study, the transmittance of a PMMA substrate after sandblasting was evaluated and the influence of sandblasting on the output of a CPV system was assessed. The transmittance of PMMA decreased with an increase in the momentum of blown sand. The conversion efficiency of a CPV module was determined by equivalent circuit calculation. The conversion efficiency decreased with increasing momentum. The coefficient of degradation was 0.17 point per unit momentum.

Abstract: ZnO thin films have successfully been deposited using DC magnetron sputtering at room temperature by means of plasma power variation. XRD results show that films were grown at a plasma power of 30 W and 40 W are polycrystalline, while at 20 W is considered as amorphous. The optical bandgap of films are shrinkage by increasing the plasma power. The broadest transmittance range is belongs to ZnO film growth at plasma power of 40 W. The electrical conductivity of ZnO films increase from 4.02x10^-7 (Ωcm)^-1 to 8.92x10^-7 (Ωcm)^-1 once the plasma power is increased. Based on the electrical and optical properties of the films it clearly be seen that ZnO film grown at plasma power of 40 W has highest transmittance and lower electrical resistivity therefore it appropriate for transparent conductive oxide (TCO).

Abstract: In order to fabricate the SiO₂ thin film using dimethyl silicone oil and ozone on protective covering glass for solar panels, the hydrophilicity and the transmittance of the film was investigated. We fabricated the film at different temperatures of 150°C, 175°C, 200°C, 225°C and 250°C on the glass substrates. The hydrophilicity of the film fabricated at 150°C showed very good hydrophilicity (water contact angle: ~8°), and transmittance was improved compared to the non-coated glass.

Abstract: Optical and photothermal properties of MWCNT-H₂O nanofluids were investigated in the present work. The transmittance of nanofluids over solar spectrum (250 to 2500nm) was measured by the UV-Vis-NIR spectrophotometer based on integrating sphere principle. The photothermal properties of nanofluids were studied expose to the solar radiation. The experimental results show that the transmittance of MWCNT-H₂O nanofluids is much less than that of deionized water, and decreases with increasing nanoparticle mass fraction. The highest temperature and heat gain of MWCNT-H₂O nanofluids (0.02wt%) can increased up to 31.87% and 54.14% compared with deionized water, respectively. From the results it can be concluded that MWCNT-H₂O nanofluids is suitable for direct absorption solar thermal energy systems.

Abstract: Surface plasmon polariton (SPP) waves exhibit local characteristics that can break diffraction limits; for this reason, the production of subwavelength optoelectronic device has been the focus of current studies. To determine the importance of surface plasmon wave applications, we aim to investigate whether or not the theoretical dispersion obtained in the plasma and metal (Drude model) exhibits the same expression, satisfy the relationship of SPPs by controlling the electron density of the plasma and the frequency of the incident electromagnetic wave, and derive the system performance parameters and plasma density parameters by changing the grating geometry and dielectric constant of the surrounding medium by using the grating structure based on surface plasmon propagation characteristics associated with sensor research. The simulation results of then design structure showed that transmission bandwidth rapidly decreases and transmission peak gradually decreases as metal dielectric thickness decreases. An SPP sensor can effectively eliminate light instability in the two wavelengths of light intensity difference to obtain anti-interference and improve the range of the measuring instrument by using two fiber-grating structure filters. Therefore, studies on surface plasmon devices for integrated application are of promotional importance.

Abstract: In this article, Cu-H₂O, Co-H₂O, MWCNT-H₂O nanofluids were prepared through two-step method. The transmittance of nanofluids over solar spectrum (250 to 2500nm) was measured by the UV-Vis-NIR spectrophotometer based on integrating sphere principle. The factors of various particle size, mass fraction and optical path influencing transmittance of nanofluids were investigated. The experimental results show that the transmittance of the three nanofluids is much less than that of deionized water. The transmittance decreased with the nanoparticle size and mass fraction increasing, but increased with the optical path length reducing. With the same mass fraction, the transmittance of MWCNT-H₂O nanofluids is the minimum. The transmittance of Co-H₂O nanofluids is higher than that of Cu-H₂O nanofluids within 250~775nm wavelength range, while inverse in 775~1370nm wavelength range. It indicates that different particle has diverse light absorption properties in different wavelength range.

Abstract: The anti-reflective SiO₂ film on glass was prepared by sol-gel process and dip-coating method.The effect of drawing speed on properties of the SiO₂ film was studied. The transmittance was tested by light spectrum transmittance testing system,the thickness and refractive index of SiO₂ film was tested by spectroscopic ellipsometer. With increasing of the drawing speed from 100mm/min to 300 mm/min, the average of transmittance increment at first increased and then decreased, which reached the maximum 4.24% at the speed 150mm/min. The relations among transmittance, thickness (d) and refractive index (n) of the SiO₂ film was dicussed.

Abstract: Atomic layer deposition (ALD) is a precision growth technique that is able to deposit either amorphous or epitaxial layer on a wide range of substrates. Multilayer thin films have been widely studied because their properties are different from those of bulk materials constituents owing to the two-dimensional films and high density of interfaces. Multilayer nanostructured thin films were fabricated on silicon and glass substrates by ALD. The optical and electrical of multilayer ZnO/TiO₂/ZnO films were investigated. The microstructure compositions and surface morphology of these multilayer films were analyzed by X-ray diffraction (XRD), Atomic force microscope (AFM) and Scanning electron microscope (SEM). The optical properties were characterized using photoluminescence (PL) and UV-VIS spectroscopy. XRD patterns confirmed that ZnO with wutrtize crystal structure and TiO₂ with anatase structure were presented. The degree of crystallinity of multilayer thin films has been improved through the deposition of ZnO. The intensity of UV luminescence of the multilayer has increased as compared to the single layer TiO₂ and bilayer ZnO/TiO₂. The multilayer ZnO/TiO₂/ZnO has high transmittance (above 80%) in visible region. All the result suggested that the use of multilayer thin films effectively enhanced the quality of films crystallinity and optical properties as compared to single layer ZnO and bilayer ZnO/TiO₂.

Abstract: Based on the experimental results of transmittance, particle swarm optimization (PSO) algorithm was adopted to establish inverse research model to calculate the refractive index and absorption index of nanofluids, we used the inverse calculation model to calculate the refractive index and absorption index of water and aqueous nanofluids, comparing inverse calculation results with experimental results, it turned out that inverse calculation model can accurately calculate the refractive index and absorption index of nanofluids.