Microwave-assisted hydrothermal synthesis of Ag/ZnO sub-microparticles

A fast and environmentally friendly, microwave-assisted, hydrothermal synthesis was utilized for the preparation of a Ag/ZnO hybrid system by using zinc acetate dihydrate and silver nitrate as the sources of ZU(2+) and Ag+, and hexamethylentetramine as the reducing and precipitating agent. The influence of the concentration was investigated by X-ray diffraction analysis, scanning electron microscopy and energy-dispersive analysis. It was found that the concentration has a strong effect on the morphology and proportion between the Ag and ZnO components of the prepared particulate materials. With a decreasing concentration, the morphology of the ZnO changed from twinned or single frustums to rod-like microparticles, whereas the silver morphology changed from large polygon-shaped microparticles to very small, spherical nanoparticles.internal grant of TBU in Zlin [IGA/FT/2013/014]; European Regional Development Fund (ERDF); national budget of the Czech Republic, within the Centre of Polymer Systems project [CZ.1.05/2.1.00/03.0111]; European Social Fund (ESF); national budget of the Czech Republic, within the "Advanced Theoretical and Experimental Studies of Polymer Systems" project [CZ.1.07/2.3.00/20.0104

Patterning of self-assembled monolayers (SAMS)

Self-assembled monolayers (SAMs) has recently received much attention because of their wide range in applications such as layers in biosensors, electronic active layers or interlayers in organic electronic devices like organic light emitting diodes (OLEDs), organic photovoltaics (OPVs), organic thin film transistors (OTFTs). Photolithography is a basic and long established technique used in the preparation of processors and other electronic components. This paper deals with patterning of self-assembled monolayers prepared on gold and silver layers using photolithography. Firstly, the prepared self-assembled monolayers were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM) and Fourier-transform infrared spectroscopy (FTIR). Subsequently testing patterns according to the resolution chart test were exposed by UV lithography. These prepared patterns were characterized by optical microscopy, atomic force microscopy (AFM) and scanning electron microscopy (SEM). © NANOCON 2019.All right reserved.Ministry of Education, Youth and Sports of the Czech Republic Program NPU I [LO1504]; Operational Program Research and Development for Innovations - European Regional Development Fund (ERDF); national budget of the Czech Republic [CZ.1.05/2.1.00/19.0409

Antimicrobial modification of polypropylene with silver nanoparticles immobilized on zinc stearate

The microwave synthesis of Ag nanoparticles on zinc stearate (ZnSt/Ag) was performed to obtain an antimicrobial additive for a polypropylene matrix. Thermoplastically prepared polymer composites contained (1, 3, 5 and 10) % of mass fractions of ZnSt/Ag. The effect of the presence of additives on the morphology and mechanical properties of composites was studied by scanning electron microscopy and stress-strain analysis. The antimicrobial activity of the composites was studied according to the ISO 22196 standard. The results showed that sufficient antimicrobial activity of the composites against both Gram-positive and Gram-negative bacterial strains was observed in the case of the composites with the highest filling studied.grant of Technology Agency of the Czech Republic [TE02000006]; Ministry of Education, Youth and Sports of the Czech Republic - Program NPU I [LO1504]; Internal Grant Agency of the Tomas Bata University in Zlin [IGA/CPS/2015/004

Cross sectioning of optoelectronic device

Optoelectronic devices play very important role in life nowadays. Most of the devices are widely used in fields ranging from image processing and fiber optic communication to common consumer electronics (twilight switches, house security systems, etc.), where components such as photodiodes, laser diodes, phototransistors, photomultipliers, optical isolators, LEDs or OLEDs are mounted. Accurate procedure is necessary during the preparation to achieve their fully functionality. Because the devices are mostly prepared as multilayer systems, there is a requirement for correct functional thickness of layers. The thickness of the layers could be checked not only during the deposition but also retrospectively in the case of some failures during their deposition. The method of ion beam milling can be used for cross section preparation and can achieve cross sections of soft materials or material combinations consisting of hard and soft components, which are used in devices. This contribution deals with case study of SEM thickness layer characterization of optoelectronic device on cross section, which was prepared by ion milling.ERDF, European Regional Development FundOperational Program Research and Development for Innovations; European Regional Development Fund (ERDF); national budget of the Czech Republic [CZ.1.05/2.1.00/19.0409]; Ministry of Education, Youth and Sports of the Czech Republic program NPUI [LO1504

Magnetorheology of core-shell carbonyl iron/ZnO rod-like particle silicone oil suspensions under oscillatory shear

The aim of this study is a preparation and application of inorganic coating on the surface of carbonyl iron particles. The two step solvothermal synthesis provides core-shell CI/ZnO rod-like morphology. Compact coating of particles has a slightly negative impact on their magnetic properties (measured for magnetic field strength in the range from 0 to 213 mT); however, there is a suitable magnetorheological performance investigated under oscillatory shear, suitable to be applied in real applications. © Published under licence by IOP Publishing Ltd

Tuning the properties of iron oxalate precursor for elongated magnetic particles

Iron (II) oxalate dihydrate was investigated as a possible candidate for the preparation of elongated magnetic particles. In order to prepare 1-dimensional nanostructures with high aspect ratio, three kinds of synthesis were employed for the preparation of this precursor. It was shown that microwave solvothermal synthesis utilizing pressurized reactor provides desired structure without the use of any surfactant in short synthesis times and uses low cost and relatively low toxic reactants

Fully inkjet-printed cuo sensor on flexible polymer substrate for alcohol vapours and humidity sensing at room temperature

This work focuses on an inkjet-fabricated sensor based on copper oxide nanostructured particles on polymer flexible substrate for the sensing of alcohol vapours and humidity at room temperature. Nanoparticles were prepared by a microwave-assisted solvothermal sealed vessel synthesis method. The ink composition was developed on the basis of viscosity and surface tension optimization by the addition of polymeric steric surfactant and dispersant. The printing process was optimized with the help of non-dimensional criteria. Silver nanoink was used for the printing of an interdigitated pattern on a PET substrate which was overprinted by the copper oxide ink, thus obtaining a flexible flat sensor. Material design and all fabrication steps of the sensor respected the temperature limitation given by the thermal stability of the polymer substrate. Printed layers and motifs were characterized microscopically and by resistance measurement. The effectiveness of the prepared sensor was demonstrated and studied by measuring the response to saturated vapours at room temperature. The sensing layer showed the opposite resistance response to stimuli than expected for the well-known p-type sensing mechanism of CuO sensors operated at high temperatures. In addition to vapour sorption, condensation and desorption influencing electron, proton and ionic conductivity, manifestation of another mechanism was observed and an explanation suggested in terms of the electrochemical mechanism. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.Ministry of Education, Youth and Sports of the Czech Republic-Program NPU I [LO1504]; Internal Grant Agency of Tomas Bata University in Zlin [IGA/CPS/2015/006, IGA/CPS/2016/007, IGA/CPS/2017/008

On-line measurement of photocatalytic activity of powdered samples

A method for on-line measurement of photocatalytic activity of powdered samples by UV-Vis spectrometry is demonstrated. It enables photocatalytic reaction to be monitored directly in the cuvette which also serves as photocatalytic reactor. The cuvette is placed inside a double beam UV-Vis spectrometer and photocatalytic reaction is driven by LED diode mounted on homemade cuvette holder housing. Diodes can be easily changed, enable photocatalytic reaction to be performed under light of various wavelengths which is beneficial when evaluating visible-light photocatalytic activity. Another advantage of the method presented lies in the simultaneous degradation of model dye solution and monitoring of reaction kinetics, which avoid sampling during the photocatalytic reaction. Measurement of photocatalytic activity is demonstrated on degradation reaction of Methylene blue 2B as the model dye by Zn2TiO4 powder under the UV (λ ∼ 365 nm), and the visible light (λ ∼ 400 nm) and (λ ∼ 425 nm) irradiation.ERDF, European Regional Development FundMinistry of Education, Youth and Sports of the Czech Republic Program NPU I [LO1504]; European Regional Development Fund (ERDF); national budget of Czech Republic [CZ.1.05/2.1.00/19.0409]; Internal Grant Agency of Tomas Bata University in Zlin [IGA/CPS/2016/006

Boosting the photoelectrochemical performance of Au/ZnO nanorods by co-occurring gradient doping and surface plasmon modification

Band bending modification of metal/semiconductor hybrid nanostructures requires low-cost and effective designs in photoelectrochemical (PEC) water splitting. To this end, it is evinced that gradient doping of Au nanoparticles (NPs) inwards the ZnO nanorods (NRs) through thermal treatment facilitated faster transport of the photo-induced charge carriers. Systematic PEC measurements show that the resulting gradient Au-doped ZnO NRs yielded a photocurrent density of 0.009 mA/cm(2) at 1.1 V (vs. NHE), which is 2.5-fold and 8-fold improved compared to those of Au-sensitized ZnO and the as-prepared ZnO NRs, respectively. The IPCE and ABPE efficiency tests confirmed the boosted photoresponse of gradient Au-incorporated ZnO NRs, particularly in the visible spectrum due to the synergistic surface plasmonic effect of Au NPs. A gradient Au dopant profile promoted the separation and transfer of the photo-induced charge carriers at the electrolyte interface via more upward band bending according to the elaborated electrochemical impedance spectroscopy and Kelvin probe force microscopy analyses. Therefore, this research presents an economical and facile strategy for preparing gradient plasmonic noble NP-incorporated semiconductor NRs, which have excellent potential in energy conversion and storage technologies.LTT20010; RP/CPS/2022/007; Tomas Bata University in Zlin, TBUMinistry of Education, Youth and Sports of the Czech Republic DKRVO [RP/CPS/2022/007]; Ministry of Education, Youth and Sports of the Czech Republic INTER-EXCELLENCE [LTT20010]; Tomas Bata University in Zli

Effect of annealing on luminescence and photocatalytic activity of ZnS nanocrystals under UV light irradiation

Zinc sulfide (ZnS) nanocrystals were prepared at a large-scale via precipitation of Zn2+ ions water solution with gaseous hydrogen sulfide, H2S. The effect of annealing time on the ZnS phase structure, morphology, and optical properties was investigated in detail by XRD, SEM, UV-vis, and photoluminescence (PL) spectroscopy. It was observed that pristine ZnS possessed a pure cubic phase structure and an increase in annealing time resulted in a phase mixture with increased content of wurtzite phase structure. Moreover, the crystallinity of the prepared samples, as well as PL intensities, increased with increasing annealing time. Photocatalytic activities of the pristine ZnS annealed at different time intervals were evaluated by the means of methyl violet 2B (MV 2B) degradation under UV LED illumination wavelengths at λmax~ 343 nm and 365 nm. It was observed that the photocatalytic activities of the annealed ZnS samples increased with increasing annealing time. The improved photocatalytic performance can be attributed to the improved crystallinity of annealed ZnS samples. © 2021 TANGER Ltd., Ostrava.Ministry of Education, Youth and Sports of the Czech RepublicMinistry of Education, Youth & Sports - Czech Republic [LTT20010]; Operational Program Research and Development for InnovationsEuropean Commission; European Regional Development Fund (ERDF)European Commission; national budget of Czech Republic, within the framework of project CPS - strengthening research capacity [CZ.1.05/2.1.00/19.0409]; Internal Grant Agency of Tomas Bata University in Zlin [IGA/CPS/2017/007]; Ministry of Education, Youth and Sports of the Czech Republic - Program NPU I [LO1504]IGA/CPS/2017/007; Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT: LTT20010; European Regional Development Fund, ERDF: CZ.1.05/2.1.00/19.040