Izrada i optička svojstva tankih slojeva MnCdS2 taloženih u kemijskoj kupki

Thin films of MnCdS2 were deposited on glass slide from aqueous solutions of MnCl2·4H2O, CdCl2·2frac12H2O and thiourea. Ammonium solutions and EDTA (or TEA) were employed as complexing agents. The optical characterization yielded band gap values in the range between 2.58 and 2.82 eV. Some of the films were found to have an average transmittance of greater than 60% in the UV-VIS regions while exhibiting high reflectance of greater than 12% in the same regions. Some of the films exhibit poor transmittance in the UV regions while exhibiting high transmittance of greater than 75% in the VIS-NIR regions. Hence, while some of the films could be effective as thermal coatings for cold climates, some could be effective as coatings against intensive sunlight as well good material for fabrication of solar cell.Proizveli smo tanke slojeve MnCdS2 na staklenim pločicama taloženjem iz vodenih otopina MnCl2·4H2O, CdCl2 · 2 1 2H2O i tiouree. Primijenili smo otopine amonijaka i EDTA (ili TEA) za kompleksiranje. Optička mjerenja dala su za procijepe vrpci vrijednosti između 2.58 i 2.82 eV. Za neke smo slojeve našli prosječnu propusnost veću od 60% u UV-VIS području, dok im je u tom području odraznost veća od 12%. Drugi slojevi pokazuju malu propusnost u UV području, a veliku propusnost u VIS-NIR području. Stoga se neki slojevi mogu rabiti kao toplinska izolacija u hladnim područjima, a drugi za zaštitu of UV zračenja i u proizvodnji solarnih ćelija

Synthesis, characterization and ab initio study of WO3 nanocubes with peculiar electrochemical properties

Simple sol–gel method has been exploited to deposit Sn-doped TiO2 thin flms on glass substrates. The resultant coatings were characterized by X-ray difraction (XRD), UV–visible techniques (UV–Vis), Fourier transform infrared spectroscopy (FTIR), and photoluminescence analysis (PL). The XRD pattern reveals an increase in crystallite size of the prepared samples with the increasing doping concentration. A decrease in doping concentrating resulted in the decrease in bandgap values. The diferent chemical bonds on these flms were identifed from their FTIR spectra. The photoluminescence analysis shows an increase in the emission peak intensity with increasing dopant concentration, and this can be attributed to the efect created due to surface states. The prepared samples were tested as antibacterial agent toward both Gram-positive and Gram-negative bacteria like S.aureus (Staphylococcus aureus) and E.coli (Escherichia coli), respectively. The size of the inhibition zones indicates that the sample shows maximum inhibitory property toward E.coli when compared to S.aureus

Study of the Effects of Thermal Annealing on the Optical Band Gap of Nanocrystalline CoO Thin Films Prepared by Chemical Bath Deposition.

Nanocrystalline films of cobalt oxide have been prepared on glass slides by chemical bath deposition process. For deposition of CoO thin films, cobaltous chloride [CoCl2.6H2O] was used as cationic and ammonia [NH3] as anionic precursor in aqueous medium. In this process NaOH was used as complexing agent. X-ray diffraction, scanning electron microscopic [SEM] analysis have been used to study the films’ crystal structures, optical and solid state properties. We hereby present the effects of thermal annealing on the optical band gap of CoO thin films. The optical transition in the films is direct one. For the as- deposited film, the band gap is 2.1eV. This later decreased to 2.08eV, so that increased thermal annealing reduces the optical band gap of CoO. However,the energy gap cannot be said to be dependent on the annealing temperatures. These films could be used as  photovoltaic cells, sensors light emitting diodes and also in biomedical imaging. Key Words: Nanocrystalline CoO, Chemical Bath Deposition, Band Gap and                               Thermal Annealing

Peculiar Size Effects in Nanoscaled Systems

In this minireview, we intend to shed light on relatively recent examples related to the size and shape effects on materials at the nanoscale and their usage to test a set of quantum mechanics governed phenomena

EFFECT OF CONCENTRATION OF Mn DOPANT IONS ON THE STRUCTURAL AND OPTICAL PROPERTIES OF ZINC OXIDE CRYSTALS

Manganese (Mn) doped ZnO crystals have been successfully grown via the gel route. Identification of the chemical species of the crystals grown was done using Fourier Transform Infrared Spectroscopy (FTIR), structural analysis was done using X-Ray Diffraction technique while the optical properties were studied using UV-VIS technique. Results from the FTIR and XRD analysis show that high concentrations of manganese dopant ions results in the formation of synthetic MnO 2 (pyrolusite), degrading the quality of the ZnO crystals