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  • Author: M. Czerniak-Reczulska x
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M. Czerniak-Reczulska, A. Niedzielska and A. Jędrzejczak

Abstract

Graphene is a two-dimensional material with honeycomb structure. Its unique mechanical, physical electrical and optical properties makes it an important industrially and economically material in the coming years. One of the application areas for graphene is the photovoltaic industry. Studies have shown that doped graphene can change one absorbed photon of a few electrons, which in practice means an increase in efficiency of solar panels. In addition, graphene has a low coefficient of light absorption 2.3% which indicates that is an almost completely transparent material. In fact, it means that solar cells based on graphene can significantly expand the absorbed spectrum wavelengths of electromagnetic radiation. Graphene additionally is a material with a very high tensile strength so it can be successfully used on the silicon, flexible and organic substrates as well. So far, significant effort has been devoted to using graphene for improving the overall performance of photovoltaic devices. It has been reported that graphene can play diverse, but positive roles such as an electrode, an active layer, an interfacial layer and an electron acceptor in photovoltaic cells. Research on solar cells containing in its structure graphene however, are still at laboratory scale. This is due to both lack the ability to produce large-sized graphene and reproducibility of its parameters

Open access

A. Niedzielska, P. Skwierczyński, M. Czerniak-Reczulska and W. Szymański

Abstract

Hydroksyapatite (HAp) as the coating, is produced using different methods of deposition, among others: laser ablation method, sol-gel, electrophoresis, thermal sputtering or magnetron spraying with the usage of high frequency. Attempts to benefit from such a wide spectrum of existing methods are related to the fact that this material possesses many advantages. We have to distinguish, among others, proper biological properties, i.e. both - high bio-tolerance and high osteo-inductivity [1,2]. However, it is worth mentioning that the material also presents disadvantages, i.e. it indicates too quick resorption within the biological environment, depending on its obtained form. In case when HAp is in the amorphous form, it undergoes a very rapid process of dissolving in the tissue environment. [3] In order to prevent the above, it is important to produce the coatings with a regulative level of cristallinity. In the presented research the hydroxyapatite coating produced using RF PACVD MS plasma method (Radio Frequency Plasma Assisted Chemical Vapor Deposition Magnetron Sputtering) possesses the above mentioned amorphous form. Nevertheless, due to the usage of ‘bubbler’, allowing for delivery of hydroxyl groups into the operating chamber, it was possible to receive the Hap coatings in a crystalline form. Changing the operating pressure (the amount of bonds - OH), during sputtering, it was checked what is the influence of that parameter on the physicochemical properties of obtained coatings. Scanning electron microscopy (SEM) was used for the founding research as well as the Roentgen Apparatus Analyser (EDS). The Phase composition of a created coating was researched using the Roentgen diffract-meter (XRD). The measures of thickness were conducted using contact-profilometry. Nano-indentation technique was used to assess the mechanical properties. Obtained results of research encourage for further researches related to the influence of hydroxyl groups on the physicochemical properties of hydroxyapatat coatings.