The replacement of SiO2 gate dielectrics with metal oxides of higher dielectric constant has led to the investigation of a wide range of materials with superior properties compared with SiO2. Despite their attractive properties, these high-k dielectrics are usually manufactured using costly vacuum-based techniques. To overcome this bottleneck, research has focused on the development of alternative deposition methods based on solution-processable metal oxides. Here we report the application of spray pyrolysis for the deposition and investigation of Al2x-1·TixOy dielectrics as a function of the [Ti(4+)]/[Ti(4+)+2·Al(3+)] ratio and their implementation in thin film transistors (TFTs) employing spray-coated ZnO as the active semiconducting channels. The films are studied by UV-visible absorption spectroscopy, spectroscopic ellipsometry, impedance spectroscopy, atomic force microscopy, X-ray diffraction and field-effect measurements. Analyses reveal amorphous Al2x-1·TixOy dielectrics that exhibit a wide band gap (∼4.5 eV), low roughness (∼0.9 nm), high dielectric constant (k ∼ 13), Schottky pinning factor S of ∼0.44 and very low leakage currents (<5 nA/cm(2)). TFTs employing stoichiometric Al2O3·TiO2 gate dielectrics and ZnO semiconducting channels exhibit excellent electron transport characteristics with low operating voltages (∼10 V), negligible hysteresis, high on/off current modulation ratio of ∼10(6), subthreshold swing (SS) of ∼550 mV/dec and electron mobility of ∼10 cm(2) V(-1) s(-1).

IrO2 shell–Ir−Ni core particulate films (denoted as IrO2 (Ir−Ni)) have been prepared by galvanic replacement of Ni layers electrodeposited on glassy carbon (GC) electrodes. The method involves three steps: immersion of the Ni/GC electrode into a deaerated solution of Ir­(IV) at 65 °C for 15 min (galvanic replacement); electrochemical treatment of the resulting Ir−Ni/GC electrode for anodic dissolution of nonreacted surface Ni and surface enrichment in Ir (formation of a precursor core–shell structure denoted as Ir (Ir−Ni)); anodization of the resulting Ir (Ir−Ni)/GC system (iridium dioxide formation). The resulting IrO2 (Ir−Ni)/GC electrodes have been characterized by SEM/EDS, AFM, and XPS, revealing a particulate morphology (submicron particles), an Ir-rich bulk atomic composition (Ir/Ni atomic ratio of ca. 5), and a thin IrO2 shell. Electrochemical characterization in acid solutions in both the H adsorption/desorption and the oxide formation/reduction potential ranges points to complete surface coverage by IrO2. The prepared IrO2 (Ir−Ni)/GC electrodes have been tested as anodes for oxygen evolution (OER) from acid solutions by means of EIS and steady-state current–potential plots; they have been proven to exhibit superior intrinsic catalytic activity for OER compared to that of plain IrO2 anodically grown on bulk Ir.

A systematic investigation of the factors influencing the notable enhancement of the mechanical and thermal properties of nanodiamonds (NDs)-reinforced cross-linked high density polyethylene (PEX) is presented in this work. The effects of crystal structure and molecular conformation as well as filler dispersion and adhesion with the matrix were found to govern the mechanical properties of the final composites. A considerable increase in the strength, toughness, and elastic modulus of the materials was found for the composites with filler content below 1 wt %. For higher NDs concentrations, the properties degraded. When filler concentration does not exceed 1 wt %, enhanced adhesion with the matrix is achieved, allowing a more successful load transfer between the filler and the matrix, thus enabling an effective reinforcement of the composites. The higher degree of crystallinity along with larger crystal size are also positively influencing the mechanical properties of PEX. Higher filler concentrations, on the other hand, lead to the formation of larger aggregates, which lead to lower adhesion with the matrix, while they also constitute stress concentrators and therefore reduce the positive reinforcement of the matrix. The thermal conductivity of the composites was also found to be significantly increased for low-filler concentrations. This enhancement was less significant for higher NDs concentrations. It is concluded that this reinforcement is due to the heat capacity increase that NDs incorporation causes in PEX. Additionally, a thermal stability enhancement was found for the composite with minimum filler content.

We report on ZnO-based thin-film transistors (TFTs) employing lanthanum aluminate gate dielectrics (LaxAl1−xOy) grown by spray pyrolysis in ambient atmosphere at 440 °C. The structural, electronic, optical, morphological, and electrical properties of the LaxAl1−xOy films and devices as a function of the lanthanum to aluminium atomic ratio were investigated using a wide range of characterization techniques such as UV-visible absorption spectroscopy, impedance spectroscopy, spectroscopic ellipsometry, atomic force microscopy, x-ray diffraction, and field-effect measurements. As-deposited LaAlOy dielectrics exhibit a wide band gap (∼6.18 eV), high dielectric constant (k ∼ 16), low roughness (∼1.9 nm), and very low leakage currents (&lt;3 nA/cm2). TFTs employing solution processed LaAlOy gate dielectrics and ZnO semiconducting channels exhibit excellent electron transport characteristics with hysteresis-free operation, low operation voltages (∼10 V), high on/off current modulation ratio of &gt;106, subthreshold swing of ∼650 mV dec−1, and electron mobility of ∼12 cm2 V−1 s−1.

Magnetic nanoparticles (MNPs) can play a distinct role in magnetic drug delivery via their distribution to the targeted area. The preparation of such MNPs is a challenging multiplex task that requires the optimization of size, magnetic, and surface properties for the achievement of desirable target selectivity, along with the sustained drug release as a prerequisite. In that context, CoFe2O4 MNPs with a small size of ∼7 nm and moderate saturation magnetization of ∼60 emu g(-1) were solvothermally synthesized in the presence of octadecylamine (ODA) with a view to investigate the functionalization route effect on the drug release. Synthetic regulations allowed us to prepare MNPs with aminated (AmMNPs) and amine-free (FAmMNPs) surface. The addition of the nonsteroidal anti-inflammatory drug with a carboxylate donor, Naproxen (NAP), was achieved by direct coupling with the NH2 groups, rendered by ODA, through the formation of an amide bond in the case of AmMNPs. In the case of FAmMNPs, indirect coupling of NAP was performed through an intermediate linker (polyethylenimine) and on PEG-ylated MNPs. FT-IR, (1)H NMR, (13)C NMR, and UV-vis data confirmed the addition of NAP, whereas diverse drug-release behavior was observed for the different functionalization approaches. The biological behavior of the MNPs@NAP was evaluated in vitro in rat serum and in vivo in mice, after radiolabeling with a γ-emitting radionuclide, (99m)Tc. The in vivo fate of MNPs@NAP carriers was in straightforward relation with the direct or indirect coupling of NAP. Furthermore, an inflammation was induced intramuscularly, where the directly coupled (99m)Tc-MNPs@NAP carriers showed increased accumulation at the inflammation site.