Solid State Phenomena Vol. 293

Abstract: The aim of study was to produce a nanocomposite polymer fibrous thin films, with the participation of the reinforcing phase in the form of TiO2/Bi2O3/SiO2 nanoparticles with a matrix of polyacrylonitrile (PAN), made by electrospinning of solution and investigation of optical and eletrical properties of obtained nanomaterials. To determination of structore of used ceramic nanoparticles the X-ray diffraction analysis (XRD) was carrying out. The morphology of the obtained polymeric and composite fibrous mats and dispersion of nanoparticles in their volume was examined using scanning electron microscopy (SEM). All the physical properties of which were: the dielectric constant, and refractive index were tested and plotted against the concentration by weight of the used reinforcing phase which was as follows: 0%, 4%, 8%, 12% for each type of nanoparticles. The optical and electrical constants of obtained thin folms was performed on the basis of UV-Vis spectra of absorbance as a function of the wavelength. Using two metods: the method proposed by the author and the recorded absorbance spectra and spectroscopic ellipsometry determined the refractive index n, real n' and imaginary k part of the refractive index as a function of the wavelength, complex dielectric permeability , real and imaginary part r and i of the dielectric permeability as a function of the wavelength of the polimeric and composite fibrous thin films.

Abstract: Today, one of the most popular nanomaterials are thin nanofibrous layers, which are used in many fields of industry, eg electronics, optics, filtration and the textile industry. They can be produced by various methods, such as drawing, template synthesis, molecular self-assembly or phase separation method, but the most common method is electrospinning from a solution or melts. Electrospinning is gaining more and more interest due to its versatility, simplicity and economy as well as the possibility of producing fibers from various types of polymeric, ceramic and metalic materials. Nanofibrous layers produced by this method are characterized by high quality and the desired physicochemical properties.

Abstract: The aim of this work is to present the influences of composition of the material and manufacturing technology conditions of the organic photovoltaics devices (OPv) with the organic and hybrid bulk heterojunction on the active layers properties and cells performance. The layers were produced by using small molecular compounds: the metal-phthalocyanine (MePc) and perylene derivatives (PTCDA) and the titanium dioxide (TiO₂) nanoparticles. Two kinds of metal phthalocyanines (NiPc, TiOPc) were used as donor material and pperylenetetracarboxylic dianhydride (PTCDA) as an acceptor. The used manufacturing technique allowed to employ thin layers of materials in a fast deposition process. Bulk heterojunction was created by simultaneously applying the MePc:PTCDA materials during the evaporation of the components mixture.The research was based on the estimate of composition of bulk heterojunction, the examination of the surface morphology of the used layers and optical properties studies of the heterojunction and its implementation to photovoltaic architecture. The produced photovoltaic cells parameters were determined on the basis of current - voltage characteristics.The researches of structure of obtained layers were conducted by using scanning electron microscope (SEM) and transmission electron microscopy (TEM). The quantitative determination of surface topography by determining RMS and Ra coefficients were performed by atomic force microscopy (AFM). In order to determine the optical properties of the films the UV-Visible spectroscope have been utilized. Current - voltage characteristics were employed to determine the basic photovoltaic parameters using a dedicated device.The paper describes the influence of the individual components sharing the bulk heterojunction on its structure, optical properties and morphology of surface. In addition it allows for linking active layers properties with the parameters of the photovoltaic cells. The obtained results suggest the possibility of developing the utilized materials and technology in the further works on photovoltaic structures.

Abstract: In this paper are presented both the fill factor of 0.75 and an efficiency approaching 14.64 % of solar cell, which were achieved, despite the non-optimized process. A new Cu-based additive of pastes were applied for formation of front contact on silicon solar cells. Front contact were screen-printed using commercial silver paste containing the CuXX additive prepared at laboratory. It is the world's first copper based paste appropriate for high-temperature production processes of front contact of the solar cell.

Abstract: In this paper, the possibility of replacing liquid electrolyte in a dye sensitized solar cells with a thin film of conductive polymer material was investigated. Liquid electrolyte in the construction of dye sensitized solar cells leaks and evaporates and leads to corrosion of the electrode, which lowers the conversion efficiency of solar radiation to electricity. The research focuses on the appropriate doping of the PVDF-HFP polymer by potassium iodide to improve its electrical conductivity and the development of thin film deposition technology for use in solar cells. Changes in PVDF-HFP surface morphology were researched through increasing of the potassium iodide content measured by scanning electron microscope. The increased content of potassium iodide also led to increased electrical conductivity measured by the Keithley meter. In order to test the suitability of developed materials for application in the construction of photovoltaic cells, a series of dye-sensitized solar cells ITO/TiO2/dye/active layer/Al were prepared. The active layer is made from pure PVDF-HFP and doped with potassium iodide. As a reference solar cell, a standard dye sensitized solar cell with a liquid electrolyte and a counter electrode was also made. Keywords PVDF-HFP; Polyelectrolyte; Dye-sensitized solar cells

Abstract: The use of thin films in optoelectronic and photovoltaic devices is aimed at improving the physical properties of the substrate material. The modification of the surface of the silicon substrate is thus one of the greatest challenges in research on photovoltaic materials, in order to achieve even greater efficiency or better adapt their properties depending on the application. The technologies of applying layers vary depending on the effect to be obtained and the material from which the layer is formed. In practice, the most common method is chemical vapor deposition and physical vapor deposition, and the most commonly applied optical materials are SiO₂, TiO₂ and Si₃N₄.This paper presents the results of investigations on morphology and optical properties of the prepared aluminium oxide thin films. Thin films were prepared with use of sol-gel spin coating method. Surface morphology studies were carried out using an atomic force microscope. To characterize the surface of the thin films, 3D images and histograms of the frequency of individual inequalities were made. In order to characterize the optical properties of Al₂O₃ thin films, the reflectance and light transmission tests were performed using a spectrophotometer. Optical constants were determined using a spectroscopic ellipsometer. Results and their analysis show that the sol-gel method allows the deposition of homogenous thin films of Al₂O₃ with the desired geometric characteristics and good optical properties. Uniform, continuous thin layers with a roughness not exceeding a few nanometres were deposited. Their deposition enabled to reduce the reflection of light from the polished substrate below 15% in a wide range (425-800nm) while maintaining high transparencies (over 90%). The obtained results causes that mentioned thin films are good potential material for optics, optoelectronics and photovoltaics.

Abstract: The article presents the results of research on tribological properties and corrosion resistance of hybrid and individual coatings embedded with the ALD (Atomic Layer Deposition) and PVD (Physical Vapour Deposition) technique on aluminum alloy substrates. Al-Si-Cu alloys coated with hybrid ALD+PVD coatings show significantly higher abrasion resistance compared to uncoated samples. In particular, the TiO₂+WC hybrid coating has the highest abrasion resistance. The highest resistance to corrosion is demonstrated by the sample with the TiO₂ type ALD coating. As a result of coating, the surface roughness of the tested samples increases, which is related to the occurrence of morphological heterogeneity in the form of solidified drops.The innovative approach of combining several technologies, while simultaneously selecting proper materials and parameters can significantly affect the future and functionality of products obtained. The technique of combining the hybrid coating technology still requires a lot of researches, the results of which can change the meaning and use of new innovative products. Keyword: PVD, ALD, hybrid coatings, TEM, corrosion resistance,

Abstract: This paper presents application examples of atomic layer deposition method (ALD) adopted for production of multifunctional thin films for various usage such as passive, antireflection and transparent conductive films. First part of this paper introduces the mechanism of ALD process, in the rest of it, aluminum oxide (as passive and antireflection) and zinc oxide (as antireflection and transparent conductive) ALD thin films are presented. In the literature one can find reports on the use of the Al₂O₃ layer as passivating and ZnO layers as a transparent conductive oxide in diodes, polymeric and dye sensitized solar cells. In this article, the ALD layers were tested for their use in silicon solar cells, using their good electrical and optical properties. For examination of prepared thin films characteristics, following research methods were used: scanning electron microscope, atomic force microscope, X-ray diffractometer, ellipsometer, UV/VIS spectrometer and resistance measurements. By depositing a layer thickness of about 80 nm, the short-circuit current on the surface of the solar cell was increased three times while reducing the reflection of light. In turn, by changing the deposition temperature of the ZnO thin film, you can control its electrical properties while maintaining high transparency. The obtained results showed that the ALD method provide the ability to produce a high quality multifunctional thin films with the required properties.

Abstract: Low friction thin layers are an excellent alternative for conventional coatings. They provide increased life of the elements, to which they were applied, due to enhancing the hardness or chemical and electrochemical resistance. They help to avoid the cracks, oxidation, as well as possible structural changes during the element's work. However, they primarily improve tribological properties by increasing wear resistance and reducing the friction. This also applies to components operating under variable conditions such as load, speed, temperature. The presented article analyzes the properties of various low-friction thin layers deposited by vacuum methods on the steel substrates. DLC, TiC, MoS2, CrCN thin layers were chosen, as they achieve the lowest possible coefficient of friction. In the framework of this work the measurements of adhesion of the investigated layers to the substrate as well as the friction coefficient, chemical analysis, microstructure and topographic analysis of the low-friction layers were carried out.