Effect of Tertiary Amines on Structural, Morphological and Optical Properties of Nanostructured ZnO Thin Film

Nanostructured ZnO thin film has been synthesized via sol-gel method. In this study, effect of stabilizer, as a vital part of sol with different molar ratios of stabilizer to Zn (stabilizer/Zn 0.25, 0.5, 1, 2), on structural, morphological and optoelectronic properties of ZnO thin film has been investigated. Triehtylamine (TeA) and triethanolamine (TEA), as two important tertiary amines for synthesize of ZnO, has been used. Spin coating technique performed to deposition of sol on glass substrate and after deposition process, the samples clacined at 500 C. X-ray diffraction method conducted in order to find structural properties of the films. The results showed the formation of hexagonal wurtzite ZnO as well as increasing the unit cell parameters by increasing TeA content. Field emission scanning electron microscopy (FESEM) used in order to see morphological changes for different molar ratios of stabilizer to Zn. The images demonstrate grain segregation in TeA samples by increasing TeA molar ratio. Also, in TEA samples, formation of micro holes in TEA/Zn 0.5 and smaller grain size for higher TEA ratios has been observed. UV-Vis spectroscopy was employed to obtain optoelectronic properties and the results have shown dependence of optical band gap to stabilizer’s type and content. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2491

Synthesis of Crack-Free PZT thin Films by Sol-gel Processing on Glass Substrate

AbstractPZT thin films deposited on glass substrates have been proposed for many applications such as adjustable optics in future X-ray telescopes. Sol-gel method is widely utilized to prepare PZT thin films due to its low reaction temperature, uniform mixing of reactants, and precise control of component. Crack-free transparent PZT thin films were prepared by dip-coating the solutions of complex alkoxides. PZT thin films were calcined at various temperatures and characterized by X-ray diffraction, field emission scanning electron microscopy to examine the surface morphology, and FT-IR spectroscopy. The XRD analysis confirmed the formation of perovskite phase at 600°C. FE-SEM results showed nucleation of PZT perovskite phase. Furthermore, the average grain size was measured in the range of 55 to 190nm

Modified BiFeO3/rGO nanocomposite by controlled synthesis to enhance adsorption and visible-light photocatalytic activity

In this study, a sol-gel process is used to synthesize a bismuth ferrite (BiFeO3, or BFO for short)/reduced graphene oxide (rGO) nanocomposite (BGO). The structural, morphological, and optical characteristics of the BiFeO3 nanopowder are modified by controlling heat treatment parameters and rGO contents. The semi-spherical BFO nanoparticles possess rhombohedral distorted perovskite crystal structure and are grafted on rGO nanosheets of various sizes which are attributed to the existence of rGO content during the sol-gel process. The observed interface between rGO nanosheets and BFO nanoparticles assists in the efficient charge separation and transfer of photogenerated BFO charge carriers through rGO nanosheets. Compared to BFO, BGO has a narrower band gap energy of 1.8 eV, a lower rate of charge carrier recombination, and stronger magnetic characteristics. The adsorption performance and photocatalytic activity mechanisms have been thoroughly examined. By adding rGO, the adsorption isotherm of methylene blue (MB) on the BFO photocatalyst changed from the Freundlich to the Langmuir. Also, the adsorption kinetics were investigated using a pseudo-second-order model. Furthermore, the degradation of MB is used to evaluate the visible light photocatalytic activity whereby 98% degradation was reached after 300 min. The Mott-Schottky test and the active species scavenger experiment are used to assess the potential mechanisms of MB photodegradation. The findings showed that the primary active species in photodegradation were hydroxyl radicals. Also, the nanocomposite was reasonably stable, and it could be magnetically removed from aqueous environments and utilized again for subsequent usage

Electrophoretic Deposition of CuIn_1–<i>x</i>Ga_<i>x</i>Se₂ Thin Films Using Solvothermal Synthesized Nanoparticles for Solar Cell Application

CuIn_1–<i>x</i>Ga_<i>x</i>Se₂ (CIGS) thin films are successfully prepared by convenient electrophoretic deposition, using colloidal nanoparticles. This is the first report which focuses on the electrophoretic deposition (EPD) of presynthesized CIGS nanoparticles directly from their colloid for solar cell application. In this research, CIGS nanoparticles are first synthesized via solvothermal process and then dispersed in a media containing a mixture of ethanol as the solvent and triethylenetetramine as the additive to be used for the film deposition via the electrophoretic method. By simple adjustment of the electrophoretic parameters, including applied voltage, pH, deposition time, and composition of nanoparticles, CIGS thin films with controlled thickness and optoelectronic properties can be fabricated. The highest photovoltaic efficiency of 5.57% is obtained in the CuIn_0.75Ga_0.25Se₂ sample. It is believed that this fabrication approach may open up a new gate to reduce the production cost of a highly demanding CIGS absorber layer used in thin film solar cells