| Abstract [eng] |
Polyamide 6 is a polymer molecule which has the following characteristics: great mechanical properties, abrasion, long term heat resistance and others [1]. These days one of the choices for substrate to make photovoltaic cells is polyamides due to their mechanical flexibility, low-cost, etc. [2]. These polymers can be coated with a variety of semiconductor materials. One of those substances are cadmium chalcogenides (CdX, X=Te,Se S). This family of compounds can be included in manufacture of light emitting diodes, solar cells, transistors [3]. Cadmium telluride (CdTe) is one the most important semiconductor material due to its optimum band gap, high absorption coefficient, n-type, p-type conductivity [4]. Most often CdTe is mixed with cadmium sulphide (CdS) owing to the same reasons: optimum band gap, p-n junction, great sunlight absorption [5]. However, great properties of binary semiconductor are highly dependent on the structural, optical, compositional ant other properties [4]. This experiment reviews the structural properties of CdTe-CdS mixture. Polyamide 6 films used in this study were 500 μm thick, with the density of 1.13 g/cm3 and the size of it was 15×70 mm. Prior to the experiments, part of the PA films was boiled in distilled water for 2 h (Sample 1, S1) while the other part films was treated in concentrated acetic acid at 20 °C for 0.5 h (Sample 2, S2). After that they were dried using a filter paper and kept in a desiccator over anhydrous CaCl2. The salts of potassium telluropentathionate (K2TeS4O61.5H2O), were prepared according to published procedure [6]. In the first stage, PA 6 films were chalcogenized from 1 to 5 h at 20 °C using an acidified (0.2 moldm–3 HCl) 0.1 moldm–3 solution of K2TeS4O6. In the second stage, PA samples were treated with the 0.1 moldm–3 solution of cadmium acetate, (Cd(CH3COO)2·2H2O), for 10 min at the temperatures of 70, 80, 90 °C. After preparation of both parts of samples, they were analysed by XRD technique on the Bruker D8 Advance diffractometer. PA 6 films were scanned over the range 2θ = 3–70° at a scanning speed of 1° min-1 using a coupled two theta/theta scan type. This analysis determined structural characterization of the obtained materials. Results obtained by XRD analysis indicated the composition and size of the crystals which formed the PA 6 films. The samples contain these compounds and elements: hexagonal cadmium telluride, orthorhombic cadmium sulphide, monoclinic sulphur and tellurium. The crystal material size is quite similar to each other, and it is mostly dependent on the preparation method. However, results show that in the S1 samples crystals sizes would increase consistently when increasing the chalcogenization time and the temperature of cadmium acetate. Meanwhile in the S2 samples crystals sizes were not consistent. It creates presumption that part of PA 6 surface was exposed to acetic acid and the layers of materials were covered unevenly. XRD analysis showed that both S1 and S2 samples layers contain similar size crystals, nevertheless the biggest crystals were obtained on the surface of the S1 sample which was chalcogenized 1 hour and treated with 90 °C cadmium acetate solution. |
