Near stoichiometric and stoichiometric CuIn(1−x)Al(x)Se2 (CIAS) thin films have been prepared by chemical bath deposition (CBD) technique. X-ray diffraction (XRD) and energy dispersive x-ray analysis (EDAX) spectra have been employed to confirm the structure and composition of the prepared films. SEM analysis of near-stoichiometric and stoichiometric CIAS thin films enabled us to estimate the grain size, to identify the growth mechanism and also to visualize the surface morphology. Transmittance spectra have been employed to determine the type of transition and other optical parameters such as absorption coefficient, extinction coefficient, dielectric constant, refractive index, Sellmeier parameters and bandgap which are reported in this paper in detail.
Cadmium oxide (CdO) thin films were grown on glass substrates by chemical bath deposition (CBD) method for different deposition times using cadmium acetate as cationic precursor. The structural and optical characterization was carried out using XRD, TEM, and UV-Vis spectrophotometer measurements. Structural analyses with XRD confirmed cubic structure of the CdO. Average particle size estimated from Rietveld refinement method of XRD pattern corresponded well with TEM measurement. The optical band gap varied between 2.35 eV to 2.48 eV with deposition time and an increase in optical band gap with decreasing film thickness was observed. The AC electrical conduction behavior of the CdO film was investigated as a function of temperature as well as frequency. The conductivity measurements indicated localized conduction and hopping of carriers between localized states. The value of real part of dielectric constant was found to decrease with frequency and increase with temperature. The Nyquist plots at different temperatures showed the existence of both grains and grain boundaries contributing to conduction mechanism.
optical properties, formation of different phases and phase relations have been investigated [ 14 – 21 ]. However, none of them is as simple and economical as the method described in this study. The optical properties and surface tension of nanoparticles are very sensitive to the method of preparation, crystallite size and doping. However, the CBD (chemical bath deposition) method is one of the simplest chemical methods in which the nanoparticles can be prepared quickly with very good crystallinity.
In the present paper, we have attempted to produce thin films of
deposition of macro- and nanocrystalline PbS and CdS have been described in literature. Among the chemical methods, chemical bath deposition (CBD) is of special interest because it is simple and highly efficient. CBD allows adjustable control of size and surface density of nanoparticles, and can be used for preparation of high-quality nanocrystalline PbS and CdS films [ 4 , 6 ]. This method has been shown to allow control of stirring period, reaction time, bath temperature, pH of solution, complexing agent and impurities [ 7 , 8 ].
Among several n-type semiconductor
Paweł Śledziński, Agnieszka Nowak, Joanna Zeyland and Ryszard Słomski
Cannabinoids impact human body by binding to cannabinoids receptors (CB1 and CB2). The two main phytocannabinoids are Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD). THC interacts with CB1 receptors occurring in central nervous system and is responsible for psychoactive properties of marijuana. CBD has low affinity to CB1 receptor, has no psychoactive characteristics and its medical applications can be wider. CB receptors are part of a complex machinery involved in regulation of many physiological processes – endocannabinoid system. Cannabinoids have found some applications in palliative medicine, but there are many reports concerning their anticancer affects. Agonists of CB1 receptors stimulate accumulation of ceramides in cancer cells, stress of endoplasmic reticulum (ER stress) and, in turn, apoptosis. Effects of cannabinoids showing low affinity to CB receptors is mediated probably by induction of reactive oxygen species production. Knowledge of antitumor activity of cannabinoids is still based only on preclinical studies and there is a necessity to conduct more experiments to assess the real potential of these compounds.
Andreea Pop, Violeta Popescu, Adrian Dinescu and Medina Batin
Copper sulfide (CuxS) films deposited on polypropylene substrate were obtained by chemical bath deposition (CBD) method. The influence of the deposition time on the morphology of CuxS films was studied by means of scanning electron microscopy. We have found that the average particles dimension increased from 37 to 49 nm with the increase of deposition time from 20 to 30 minutes. The study of optical properties of the copper sulfide films was carried out based on optical transmission spectra recorded in the 400–1000 nm wavelength range. The optical constants, such as refractive index, extinction coefficient and dielectric constant as well as electrical and optical conductivity of CuxS films were calculated. The obtained values are in accordance with the ones reported in the literature:We have shown that both, morphological and optical properties of CuxS films are strongly affected by the deposition time.
Veronika Jarábková, Lenka Tišáková and Andrej Godány
Endolysins are bacteriophage-encoded peptidoglycan hydrolases, which are synthesized in the end of phage reproduction cycle, in an infected host cell. Usually, for endolysins from phages that infect Gram-positive bacteria, a modular structure is typical. Therefore, these are composed of at least two separate functional domains: an N-terminal catalytic domain (EAD) and a C-terminal cell wall binding domain (CBD). Specific ligand recognition of CBDs and following peptidoglycan (PG) binding mostly allows a rapid lytic activity of an EAD. Here we briefly characterize phage endolysin CBDs in conjuction with their domain architecture, (non)necessity for the following lytic activity and a high/low specificity of their ligands as well. Such an overall assessment of CBDs may help to find new ways to widen opportunities in their protein design to create ‛designer recombinant endolysins’ with diverse applications.
business district of Lourenco Marques, Mocambique. In: Economic Geography, Volume 38, Issue 1, Clark University, pp. 56-77. Stable URL: http://www. jstor.org/stable/142325
Bohnert, J.E. and Mattingly, P.F., 1964: Delimitation of the CBD through time. In: Economic Geography, Volume 40, Issue 4, Clark University, pp. 337-347.
Borruso, G., 2003: Network density and the delimitation of urban areas. In: Transactions in GIS, Volume 7, Issue 2, John Wiley and Sons Ltd, pp. 177-191. DOI: http://dx.doi.org/10
Synthesis and characterization of Mn-doped Sb2S3 thin films (TFs) prepared by chemical bath deposition (CBD) at room temperature have been documented and their structural, optical, morphological, magnetic and photovoltaic properties have been examined for the first time. Their structural properties reveal that the Mn-doped Sb2S3 TF has an orthorhombic phase structure of Sb2S3, and that the grain size of the Mn-doped Sb2S3 TF (72.9 nm) becomes larger than that of undoped Sb2S3 TF (69.3 nm). It has been observed that Mn content causes the Sb2S3 TF band gap to decrease. This situation clearly correlates with band tailing due to the impurities that are involved. The morphological properties have revealed that the shape of the Mn-doped Sb2S3 TF is more uniform than the shape of its undoped counterpart. The study on its magnetic properties has demonstrated that the Mn-doped Sb2S3 TF exhibits paramagnetic behavior. Its paramagnetic Curie-Weiss temperature was found to be -4.1 K. This result suggests that there is an anti-ferromagnetic interaction between Mn moments in the Mn-doped Sb2S3 TF. Incident photon to electron conversion efficiency (IPCE) and J-V measurements were also carried out for the Mn-doped Sb2S3 TF for the first time. The results have indicated that the Mn-doped Sb2S3 TF can be utilized as a sensitizer to improve the performance of solar cells. Another important observation on the photovoltaic properties of Mn-doped Sb2S3 TF is that the spectral response range is wider than that of undoped Sb2S3 TF. Our study suggests that the introduction of dopant could serve as an effective means of improving the device performance of solar cells.
Nanocrystalline zinc sulfide thin films were prepared on glass substrates by chemical bath deposition method using aqueous solutions of zinc chloride, thiourea ammonium hydroxide along with non-toxic complexing agent trisodium citrate in alkaline medium at 80 °C. The effect of deposition time and annealing on the properties of ZnS thin films was investigated by X-ray diffraction, scanning electron microscopy, optical transmittance spectroscopy and four-point probe method. The X-ray diffraction analysis showed that the samples exhibited cubic sphalerite structure with preferential orientation along 〈2 0 0〉 direction. Scanning electron microscopy micrographs revealed uniform surface coverage, UV-Vis (300 nm to 800 nm) spectrophotometric measurements showed transparency of the films (transmittance ranging from 69 % to 81 %), with a direct allowed energy band gap in the range of 3.87 eV to 4.03 eV. After thermal annealing at 500 °C for 120 min, the transmittance increased up to 87 %. Moreover, the electrical conductivity of the deposited films increased with increasing of the deposition time from 0.35 × 10−4 Ω·cm−1 to 2.7 × 10−4 Ω·cm−1.