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This study investigates the influence of chemically synthesized Al2O3 dielectric layers on the performance of both metal–insulator-metal (MIM) capacitors (FTO/Al2O3/Au) and transparent thin film transistors (TTFTs) (FTO/Al2O3/ZnO/Au). Using two distinct formulations, a detail comparison based on varying precursors concentrations and the deposition time is presented. Scanning electron microscopy shows a nanopore morphology in the Al2O3 dielectric layers. Electrical characterizations for MIM devices yielded leakage currents around 6 × 10 - 4 A ∙ cm 2 and capacitance values in the 107–77 nF/cm2 range. For TTFTs, drain current vs drain-source voltage (ID-VDS) ( ∼ 1 - 8.5 μ A ) and drain current vs gate voltage (ID-VGS) (on/off ratio 2.4 × 102) were measured with chemically synthesized ZnO. Using a zinc oxide semiconductor as the active channel, the threshold voltage (Von/off = ~ 36 V) and mobility (µ = 1.23 cm2/Vs) was obtained. The application of Al2O3 as the dielectric gate, which acts as a substrate for ZnO deposition during device fabrication, induced a ZnO dendritic-like surface morphology, influencing channel conduction and exhibiting distinctive electrical behaviors corresponding to each formulation. Beyond the demonstrated capabilities of Al2O3 in these devices, this material demonstrates advantages for highly transparent and effective low-cost device fabrication. [ABSTRACT FROM AUTHOR]

Nanocomposite gels are novel materials mainly used in the medical field for the control drug release and distribution. In this study, the effect of the concentration of galactomannan/zinc oxide nanocomposite in a polymeric Carbopol matrix to obtain a functional nanocomposite gel was studied. The swelling, thermogravimetric, rheological, and antibacterial properties against Escherichia coli and Staphylococcus aureus were evaluated. The results indicate that there is a direct effect between the amount of the employed nanocomposite and the properties studied in the gels. In this regard, we present a formulation that demonstrates that the prepared nanocomposite gel has ideal properties to be used in the medical field as an antibacterial agent. [ABSTRACT FROM AUTHOR]

This paper describes studies performed to understand the biocompatibility of TiO2 thin films with controlled crystalline phases using human pigment epithelium cells (ARPE-19). TiO2 films were deposited by radio frequency magnetron sputtering using different gas pressure, oxygen partial pressure and magnetron power. Thermal annealing was used to control the microstructure and crystalline phase of the resulting films. Results show that films deposited at low power (75 and 100 W) developed anatase phase and as power increases (>125 W), a mixture of rutile and anatase is observed. For films deposited at higher power (>150 W), only rutile phase was obtained. These results indicate that plasma power is a critical parameter to control TiO2 crystalline phase. Finally, 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay showed that there is no significative difference in cell proliferation among TiO2 crystalline phases and indicates that the biocompatibility is mostly defined by the surface chemistry of the films. [ABSTRACT FROM AUTHOR]

The present study concerns the methodology for the successful synthesis of galactomannan/ZnO (GM/ZnO) nanocomposite using an in situ chemical co-precipitation route utilizing galactomannan as a nanoreactor. The galactomannan was isolated using a hydrothermal extraction from mezquite (Prosopis spp.) seeds, in which the tree represents a valuable resource for the habitants of arid and semiarid zones of Mexico. The GM/ZnO was synthesized at room temperature. The effects of changing the galactomannan concentration in the nanocomposite over the antibacterial activity against Escherichia coli and Staphylococcus aureus were investigated by microdilution broth method. The GM/ZnO with greatest antibacterial activity was the one with the lowest amount of galactomannan and it was characterized. The ZnO nanoparticles that were observed by SEM and TEM, showed the formation of ZnO nanoparticles, with flake/petal shape and wurtzite structure. The synthesis of nanocomposite was confirmed by FTIR, with strong interactions between the primary alcohol of the galactomannan and ZnO. The thermal stability and decomposition was determined by TGA and DSC, finding a greater thermal stability and an increase of the degradation temperature. A mechanism for the synthesis of GM/ZnO, as well as the formation model of the ZnO with the assistance of the galactomannan are proposed. [ABSTRACT FROM AUTHOR]