Papers by Keyword: Transmittance

Abstract: Aluminum-doped NiO thin films were generated on glass substrates by dip coating at different temperatures (400 to 500 °C) using 0.05 M of the precursor nickel acetate. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to investigate the structural and morphological aspects of the films. UV-visible spectroscopy was utilized to assess the optical properties of the films, and the energy band gap was confirmed to be 3.42,3.6, and 3.8 eV for as-prepared and thin films, respectively. Photoluminescence (PL) measurements were used to investigate electronic faults. The XRD lines of the transferred Al-doped NiO were strengthened due to the fact the film's temperature content increased due to the improved crystalline structure. This research article focuses on the optical properties and morphologies of thin films which have been deposited. Crystalline proportions of the thin films that were deposited were determined using the Debye-Scherer formula. The outcomes were computed after taking measurements of absorbance (A), transmittance and Band Gap.

Abstract: Among the numerous metal oxide semiconductors, zinc oxide (ZnO) is one of the most widely used materials in various fields due to its non-toxic nature, tunable electric and optical properties, and good thermal and chemical stability. This research aims to study the tuning of optical, electrical, and surface properties of ZnO film treated with dielectric barrier discharge (DBD) plasma produced at atmospheric pressure. The result revealed a significant decrease in its optical band gap, but there was an increase in conductivity. The results of contact angle measurement clearly showed the change of surface nature from hydrophobic to hydrophilic for DBD-treated ZnO film.

Abstract: Multilayer antireflection coatings have been modeled in visible and infrared regions (1-5 μm) bands to increase the transmittance of glass and silicon substrates. The transmittance was studied using different semiconductor materials with different thickness ( single, double and three) layers to determine the best design that depends on the manufacture of antireflection coatings at low costs and few layers of coatings to reduce the stress generated by the increased number of layers. MgF₂ and TiO₂ materials are used in the visible region (300-1000 nm) at the central wavelength (500 nm). The transmittance of MgF₂ single–layer with a quarter waves optical thickness is reached (98.61%) and the transmittance value is (98.74%) for arrangement (. The transmittance of the infrared spectrum for antireflection coating materials depends on the thickness and temperature of these materials because of scattering and absorption in such materials. LaF₃, ZrO₂, ZnSe, and CdTe materials are used in the infrared region at a design wavelength (3000 nm). The maximum value of transmittance is around (99.99%) for the best design that consisting of three layers with quarter wavelength thickness. Keywords: Antireflection Coatings, Multilayers, Semiconductor, Transmittance

Abstract: Bruggeman's symmetric effective-medium model of vanadium oxide is introduced, in which the transmittance was studied because of its importance in the subject of smart windows, it was studied from ( 5 nm-1000 nm) for each of the regions of the electromagnetic spectrum, the ultraviolet and visible region, and the near and medium sub-regions of the infrared and the results showed that the importance of studying the transmittance of vanadium oxide as a good candidate For this kind of industries. Our results showed that the small sizes of the material guarantee an almost constant and high transmittance to the visible region; this is due to the agreement of the direction of the dipoles in the material with the direction of the internal electric field, which leads to an increase in the value of the refractive index. The refractive index represents the gain in the permittivity of the material presented by Bruggeman's model. For the other regions where the transmittance is not desirable, it can be controlled by the film’s size of the transmittance on the one hand and the wavelength on the other hand.

Abstract: Y₂Ti₂O₇ transparent ceramic was fabricated by reactive sintering using spark plasma sintering at 1673 K for 2.7 ks. The sintered body exhibited a cubic pyrochlore structure and uniform microstructure with an average grain size of 2.9 μm. The transmittance reached 73% at a wavelength of 2000 nm after annealing at 1023 K for 21.6 ks.

Abstract: Micro-structured optical film is one of the micro-optical elements and has a great market demand. This article studies the microstructured optical film formed by UV imprinting: The influence of embossing pressure on microstructure replication accuracy was explored. The larger the pressure, the better the material filling. When the pressure is 5N, the microstructure replication is complete; The relationship between the radiation intensity and warpage deformation was explored, and the decrease in the intensity of the UV light source can effectively reduce the warpage deformation; The influence of the material formula on the optical properties of the product was explored. When the oligomer content was 55%, the film had a high light transmittance. At the same time, the prepared film was subjected to an apparent inspection with good microstructure replication accuracy.Microstructured optical elements are widely used in optical fields such as semiconductors, lasers, beam shaping ^[1-2] and solar energy ^[3-5] due to their unique advantages such as small size and high performance. As a key component in many industries, it has a high market demand rate. However, the microstructure forming process is complicated, the manufacturing cost is high, and the accuracy is difficult to guarantee, which has restricted its development. With the advancement of science and technology and the increase in market demand, more and more researchers and enterprises have put their eyes on the research of preparing micro-structured optical elements.At present, the commonly used microstructures are mainly icrolens array ^[6-8], and the processing methods include micro-imprinting ^[9-10], etching ^[11], electron beam direct writing, and micro-injection ^[12], etc. This article studies the UV-curing embossing process in micro-embossing. This processing method has the advantages of fast molding, high efficiency, and environmental protection. And this process is conducive to mass production and has a broad market application prospect.In this paper, the forming process and material formulation of microstructured optical film prepared by light-cured micro-imprinting were investigated, and the microstructure morphology of the preparation was analyzed apparently.

Abstract: In this paper, we report on synthesis of graphene film on Cu foil by cold wall CVD and successfully transferred to a photovoltaic cell. The obtained sample was covered with an ultra-thin layer of Ni, of about 4 nm, using a sputtering technique. The optical and electrical properties of graphene/Ni-based films showed superior performance (transmittance =65%, sheet resistance=250 Ω/sq; EQE=40%) compared to films made of ITO/nickel, described in literature, of greater thickness.

Abstract: Tandem Solar Cells with Silicon as one of its constituents have flat surfaces (surfaces without texturing). That is why flat surfaces Solar cells have got quite importance. But the issue with the flat surfaces is the high reflection loss (flat) and poor light trapping (no-texturing) in the cells. So, some scattering film, other than direct texturing, that is polydimethylsiloxane (PDMS) polymer with the texture is used. The optimized PDMS film here is the random pyramidal film because random pyramidal PDMS films have a drop of 56.6% in reflectance used on polished Silicon while iso-textured and inverted pyramids have 51.55% and 48.47% respectively. This PDMS film with random textures when applied to 2-terminal monolithic perovskite/Silicon tandem, its external quantum efficiency shows an increase of 1.12mA/cm² in the short-circuit current and reflection loss reduces by 4.1 mA/cm².

Abstract: A simple on-site transmittance measurement setup that is easy to move and install is proposed in this study. It is especially suitable for those cases when laboratory instruments are not applicable. Ordinarily, witness samples are measured since the uniformity is good enough inside the thin film coator and the size of the sample is proper for the facilities to measure. When the spot size of the measuring instrument is too large for the filter or the size of the test sample is too large to fit into the instrument. The proposed setup is shown to work well for this measurement. An application for this setup is also presented. The test target was a stripe filter, which has five band-pass thin films and nominal dimensions of 120 x 3.6 mm each film. Distance between neighboring films is 3.85 mm. The width of each film is so narrow and the size the stripe filter is large such that the traditional method for spectral transmittance is not applicable. The proposed measurement setup consists of a light source, integration sphere and spectrophotometer. The setup was installed inside a dark room. It shows that the setup can provide as accurate results as those data measured by an accreditated instrument. The difference between the present setup and accreditated instrument was found within 7% for high radiance. When the radiance of the incident light is low the accuracy decreases, which can be compensated by stronger light source. In addition, since the measurement spot size is estimated as 1.5 x 2.1 mm it can provide local transmittance data along the stripe thin film rather than a single data represented by the witness sample.

Abstract: An investigation has been done to study the influence of the Fe and Al doping concentration on the optical properties of zinc oxide thin films. A spray pyrolysis system was used to obtain ZnO:M films doped with Iron and Aluminum, using zinc acetate dihydrate, hydrated iron chlorate and hydrated aluminum chlorate, respectively. The temperature and the concentration were fixed at 450°C and 0.1mol/L, respectively. Our thin films deposed on glass substrate. UV-VIS spectrophotometer has been used for the layers characterization. The optical transmittance spectra showed that the 2% Al dopand improves the optical transmittance in the visible that the Fe dopand. Zinc oxide thin films is the n type semiconductor with direct optical band gap varied between 3.219-3.346eV for obtain the films in photovoltaic application. But the urbach energy of ZnO thin films undoped and doped by Iron and Aluminum is varied between 101– 202 meV.