Nanocrystalline Flash Annealed Nickel Oxide for Large Area Perovskite Solar Cells.

The industrialization of perovskite solar cells requires adequate materials and processes to make them economically viable and environmentally sustainable. Despite promising results in terms of power conversion efficiency and operational stability, several hole-transport layers currently in use still need to prove their industrial feasibility. This work demonstrates the use of nanocrystalline nickel oxide produced through flash infrared annealing (FIRA), considerably reducing the materials cost, production time, energy, and the amount of solvents required for the hole transport layer. X-ray photoelectron spectroscopy reveals a better conversion to nickel oxide and a higher oxygen-to-nickel ratio for the FIRA films as compared to control annealing methods, resulting in higher device efficiency and operational stability. Planar inverted solar cells produced with triple cation perovskite absorber result in 16.7% power conversion efficiency for 1 cm2 devices, and 15.9% averaged over an area of 17 cm2 .

New Insights on the Effects of Water on Polymer Inclusion Membranes Containing Aliquat 336 Derivatives as Carriers.

Surface characterization of polymer inclusion membranes (PIMs) using the polymers cellulose triacetate and polyvinyl chloride, containing different ionic liquids (ILs) as carriers, has been performed. Three different ILs have been tested: commercial trioctyl methylammonium chloride (Aliquat 336-AlqCl-) and two derivatives bearing the counter anion NO3- or SCN- (AlqNO3 and AlqSCN, respectively). Surface analysis was performed by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) for both dry membranes and PIMs immersed for 4 days in ultrapure water to investigate the effect of the interaction of water with the membrane's morphology and composition. XPS analysis of the PIMs revealed that immersion in ultrapure water causes a decrease in the atomic concentration percentage (A.C.%) of the specific IL atoms (Cl, S, and N) when compared with dry samples. Moreover, SEM images of the PIMs containing the IL AlqNO3 showed an alteration in the morphology of the membrane due to water contact at surface level, whereas no changes were observed at a bulk level. These changes in the surface composition of the water equilibrated PIMs may be associated with the solubilization of the IL in the water solution, which, therefore, may affect the reactivity of the membrane's surface. To better understand this effect, PIMs containing both AlqCl and AlqNO3 as carriers were used for arsenic (V) transport. It was found that AlqCl was the most effective IL and that the effectivity of the PIM on As(V) removal was not affected after five cycles of the membrane's reuse.

Functional Antimicrobial Surface Coatings Deposited onto Nanostructured 316L Food-Grade Stainless Steel.

In our study, we demonstrated the performance of antimicrobial coatings on properly functionalized and nanostructured 316L food-grade stainless steel pipelines. For the fabrication of these functional coatings, we employed facile and low-cost electrochemical techniques and surface modification processes. The development of a nanoporous structure on the 316L stainless steel surface was performed by following an electropolishing process in an electrolytic bath, at a constant anodic voltage of 40 V for 10 min, while the temperature was maintained between 0 and 10 °C. Subsequently, we incorporated on this nanostructure additional coatings with antimicrobial and bactericide properties, such as Ag nanoparticles, Ag films, or TiO2 thin layers. These functional coatings were grown on the nanostructured substrate by following electroless process, electrochemical deposition, and atomic layer deposition (ALD) techniques. Then, we analyzed the antimicrobial efficiency of these functionalized materials against different biofilms types (Candida parapsilosis, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus epidermidis). The results of the present study demonstrate that the nanostructuring and surface functionalization processes constitute a promising route to fabricate novel functional materials exhibiting highly efficient antimicrobial features. In fact, we have shown that our use of an appropriated association of TiO2 layer and Ag nanoparticle coatings over the nanostructured 316L stainless steel exhibited an excellent antimicrobial behavior for all biofilms examined.

Insight into the hybrid luminescence showed by carbon dots and molecular fluorophores in solution.

Carbon dots have attracted great attention from the research community given their very attractive luminescent properties. However, the recent discovery that some of these properties may result from fluorescent impurities originating from the synthesis process, and not from the carbon dots themselves, constitute a significant setback to our knowledge of these materials. Herein, we proceeded to the study of carbon dots generated from citric acid and urea via a microwave-assisted synthesis, focusing on their analysis by AFM, HR-TEM, XPS, FT-IR, ESI-MS, UV-Vis and fluorescence spectroscopy. We have found that this synthesis process does generate molecular fluorophores that can mask the luminescence of the carbon dots. More importantly, our data demonstrates that when present in the same solution, the carbon dots and these fluorophores do not behave as separated species with individual emission. Instead, they interact to produce a hybrid luminescence, which excited state properties and reactivity are different from the properties of the individual species. These results indicate the possibility for the development of hybrid materials composed by carbon dots and related molecular fluorophores with new and improved properties.

Preparation, chemical and electrical characterizations of lipid nanoparticles loaded with dihydroxybenzophenone.

Lipid nanoparticles loading the sunscreen 2,4-dihydroxybenzophenone (DHB-LNPs) have been prepared by high-pressure homogenization and ultrasound techniques. The combination of both methodologies improves the entrapment efficiency percentage reaching 95%. The morphology of the DHB-LNPs was studied with scanning electron microscopy (SEM) and atomic force microscopy (AFM), while the surface and interior chemical composition was analyzed by X-ray photoelectron spectroscopy (XPS) at different irradiation times. Conductivity of aqueous dispersions of the DHBLNPs was determined by impedance spectroscopy. A possible DHB-LNPs application related to drug release in a system simulating skin-properties is shown.