Plasmonic metastructures represent a class of bidimensional metamaterials that can be designed and optimized to realize optical sensors aiming a wide variety of actual applications. In this work we propose a modelling approach for such metasurfaces based on a customized particle swarm optimization (PSO) algorithm implemented in the commercial Ansys Lumerical FDTD software. Providing to the algorithm the relevant optical and morphological parameters, we obtain a set of optimized geometrical parameters tailored to the required usage based on a specific fitness function mimicking the actual experimental measurement configuration. The requirements can be associated with different lithographic techniques. Specific constraints on piloting compatibility and scaling up processes are also implemented. Two different array dispositions have been analyzed: square and hexagonal arrays of air cylinders in a gold layer on a glass substrate. In our more recent activities, we are dealing with gold nanohole arrays for biosensing applications for biosensors based on surface plasmon resonance (SPR) measurements. Consequently, we focused our study on tuning the main localized plasmon resonance in the near infrared to maximize the effectiveness in SPR detection. In the end, two suitable structures have been successfully defined, one for each array disposition, that we have already planned to fabricate, in order to validate our design routine.

Bacterial colonization of the biomaterials placed in the human body and resulting inflammation of the surrounding tissues induced a need for development of methods of the surface modification of the implant materials aimed at obtaining an antibacterial effect. Micro-arc oxidation (MAO) turned to be very popular due to its versatility, control-ability and environmental-friendliness. Simplicity in controlling the electrolyte components makes the incorporation of antibacterial agents possible. Nanoparticles (metallic and ceramic) gained in importance out as a large surface-area-to-volume ratio allows substantial amounts of ions of antibacterial additive to be released with the aim to interact with the outer membrane of the bacteria and subsequently with its DNA causing a disruption of its functioning. Even if many literature reports confirmed considerable antibacterial effect of the MAO coatings with selected nanoparticles, their microstructure formation remains sparsely investigated.

In this work, titanium of commercially purity, subjected to hydrostatic extrusion, has been micro-arc oxidized in the electrolyte bath containing sodium phosphate and as-supplied nanoparticles or acetates to produce titania coatings with embedded nanoparticles. In this way, metallic and ceramic nanoparticles have been incorporated. The application of the substrate material presenting a significant anisotropy additionally influences the microstructure formation. Advanced methods of scanning and transmission electron microscopy were used in order to optimize MAO fabrication process and unveil the mechanisms of incorporation of antibacterial additions into the coating.

Acknowledgements

This research was done in the frame of the project funded by the National Science Center of Poland, grant number UMO-2020/39/D/ST8/01783.

Recently, photocatalysts have been attracting much attention due to application in the different humanity problems such as air and water purification, generation of green fuels via water splitting and CO₂ reduction. One of the most popular photocatalysts actively studied in the present is graphitic carbon nitride (g-C₃N₄). g-C₃N₄ demonstrates significant photocatalytic performance even in the visible range, but its efficiency is limited by the recombination of photogenerated electron hole pairs. Formation of composites such as g-C₃N₄/WO₃ improves photocatalytic properties compared to the individual catalyst due to separation charge carriers on the semiconductors contact.

The aim of this research was determination of optimal conditions in the hydrothermal synthesis resulting in both WO₃ nanoparticles precipitation on the g-C₃N₄ surface and saving initial g-C₃N₄ structure. Thereby, we synthesized g-C₃N₄/WO₃ composites via hydrothermal treatment of g-C₃N₄ in the acidic tungstates solutions and studied synthesis parameters effect on the obtained composites’ structure and photocatalytic activities. Initial g-C₃N₄ was obtained using classical melamine thermolysis approach. On the other hand, its structure and composition changes under hydrothermal condition were determined by FTIR-spectroscopy and CHNO-analysis. Hydrothermal syntheses of composites g-C₃N₄/WO₃ were carried out at different treatment times and pH values. Powder XRD analysis with SEM data proved WO₃ formation on the g-C₃N₄ surface from sodium tungstate solution. The studying of the photocatalytic performance of the WO₃/g-C₃N₄ composites was evaluated in the reaction of hydrogen peroxide generation from oxygen under UV irradiation. The WO₃/g-C₃N₄ composites demonstrated three times better photocatalytic activity than the individual semiconductor photocatalyst obtained in the same conditions.

It is known that carbon nanomaterials have unique properties, which are determined by their surface chemistry and developed porous structure. They are widely used as fillers of composite materials, microporous adsorbents, catalyst carriers of organic synthesis processes, and are also excellent absorbers of electromagnetic radiation. In particular, they can be used as a material for stealth technologies in the production of protective coatings for the military. The development of methods for purposeful modification of the surface of carbon materials is relevant, which makes it possible to create special protective materials for shielding.

Different types of oxygen-containing groups are present on the activated carbon (AC) surface: carboxylic, lactonic, anhydride and phenolic, which can interact with functional groups of polymer matrices when creating composite materials, which is important for creating new classes of substances with predetermined properties. TGA, TPDIR and TPDMS methods were used, in particular, to determine the concentration and study the thermal stability of oxygen-containing functional groups of AC. The morphology of AC was studied by the SEM method. A series of samples in the form of films was obtained by the method of thermal pressing of polyvinyl chloride (PVC) powders and activated carbon in different mass ratios.

When studying the microwave properties of the obtained films of PVC/AC composite materials, it was found that with an increase in the percentage mass of AC, the reflection coefficient of electromagnetic waves from the sample increases, and it appears that this change occurs according to a linear law. Concentrations of AC up to 5% make changes in the reflection coefficient of the order of 10%, concentration of AC greater than 20% increases the reflection coefficient by 3 times. This trend is also visible from the results for the standing wave coefficient at AC concentrations greater than 20% (VSWR>∞).

One of the main concerns about the rapid development of modern industrialization worldwide is the increased environmental contaminants, including several harmful molecular and ionic species (e.g., gases, pesticides, heavy metals, and pharmaceutics). It is crucial the development of new and low-cost materials for the efficient and rapid optical detection of the lower amounts of these environmental contaminants in real water samples.

Two-dimensional (2D) materials, such as graphene and derived materials (e.g. graphene oxide: GO), have attracted significant attention due to their unique optical properties, well-defined architecture and tunable surface chemistry, making them excellent platforms for optical sensing applications. Combining such 2D materials with metallic nanoparticles (MNPs) allows the fabrication of highly sensitive surface-enhanced Raman scattering (SERS) substrates for analytical purposes.

Here, we report our research on chemical strategies to decorate GO membranes with Au nanostars (AuNSs) to produce easy-handled and highly sensitive analytical platforms, envisaging the spectroscopic detection of vestigial organic pollutants dissolved in contaminated water. The organic dye methylene blue (MB) was used here as a water pollutant model because it is a cationic dye widely used for dying textiles and wood. MB produces potentially carcinogenic aromatic amines such as benzidine and methylene and is well-known for its high SERS activity. Several preparative approaches were employed to fabricate these hybrid materials, and their impact on MB SERS detection was evaluated. These include using polyelectrolytes, distinct graphene-based materials, and the deposition method of the AuNSs.

During the last ten years perovskite solar cell (PSC) technology gained the world scientific interest because of some peculiar features as the high absorption coefficient and the carrier transportation that permit to reach efficiencies about 26%. A typical PSC can be obtained by a n-i-p junction where the perovskite is the intrinsic semiconductor sandwiched between a p-type (HTM, Hole Transporting Material) and n-type (ETM, Electron Transporting Material) semiconductor. The HTM is the main source of instability within the solar cell stack. In the standard structure, on top of the HTM a metal counter-electrode is thermally evaporated. Gold is the most used counter-electrode for high efficiency cells, but it is corroded by halogen ions expensive. For these reasons, the HTM and the metal top-electrode can be replaced by a cheap low temperature firing carbon black/graphite layer. Carbon-based perovskite solar cells (C-PSCs) are a cell concept introduced to address the issues of instability, manufacturing complexity and high costs. Low temperature (T<100°) carbon-based electrodes have been widely applied in perovskite solar cells because of their chemical inertness and compatibility with up-scalable techniques, signifying their solid potential for mass-production. If the low-cost perspective is achieved through the carbon electrode that avoid high-vacuum thermal evaporation of gold electrode, there is still a lack of efficiency for this type of PSCs. In this work we optimized the low temperature carbon based cell structure by blade-coating a carbon-based ink as counter-electrode.

The influence of functionalised graphene nanoplatelets with melamine on the thermal and mechanical properties of a 3D printed photopolymerisable resin is investigated. In this work, a liquid-based 3D printer, stereolithography, was employed to fabricate the 3D printed parts, and a commercial dimethacrylate-based resin was used. The 3D printed parts were subjected to ultraviolet and thermal post-curing stages to improve thermal and mechanical behaviour. The quality of the graphene nanoplatelets functionalisation was characterised by Fourier transform infrared spectroscopy and thermogravimetric analysis. Thermal and mechanical characterisation of the 3D printed nanocomposites were performed via thermogravimetric, tensile and Izod impact tests. The fractured surfaces were observed via scanning electron microscopy. The degree of graphene nanoplatelets dispersion in the polymer matrix is enhanced by bonding with melamine via π-π interactions and inhibited surface defect formation. Results show property enhancements of up to 35% in tensile strength, 78% in impact strength and 38% in residual weight at 400 °C. The improvement in thermal stability, tensile and impact properties with such a small amount of functionalised graphene nanoplatelets is owing to the strong interfacial adhesion between functionalised graphene nanoplatelets and the 3D printed polymer matrix. This in turn enhanced the UV curing reaction with the dimethacrylate-based photocurable resin.

Metal-organic frameworks (MOFs) are an evolving class of crystalline porous materials made of organic linkers and metallic nodes. The rich chemistry of MOFs allows them to have an almost infinite number of possible structures. Consequently, they have been of great interest because of their highly-tunable properties and unique features, such as their high porosity, high surface area, structural stability, structural diversity, and tailorability. These enable MOFs to be a flexible catalytic platform for photocatalytic applications. Thus, this paper discusses the opportunities of MOFs for use in catalysis. In particular, the use of metal-organic frameworks as a photocatalyst is briefly discussed. Specifically, MOFs can be used as a photocatalyst for carbon dioxide reduction (CO₂RR), nitrogen reduction reaction (NRR), and water splitting reaction (HER, OER, ORR). However, using MOFs as catalytic platforms has some challenges that must be addressed to achieve commercialization. Therefore, this paper also discusses some prospects of designing MOFs for their specific catalytic applications to improve their catalytic properties and enhance selectivity. More importantly, an outlook is also provided on how MOF catalysts can further be developed to enable other catalytic reactions. Overall, MOFs have great potential as a photocatalytic material, provided they are uniquely designed to suit their intended applications.

Cerium oxide is widely used in chemical mechanisms, fuel cells, etc. on the other hand yttrium oxide nanoparticle is acquainted with practical applications because others have higher dielectric constant and thermal stability, both are rare and noble earth metals. In this study, YCeO nanocomposites were efficaciously synthesized by the hydrothermal method in the company of sodium hydroxide as a reducing agent as well as cerium nitrate and yttrium nitrate as a precursor. Synthesis temperature and pressure, during hydrothermal reactions, show a critical role in governing the shape, size, oxygen vacancy attentiveness, and low-temperature reducibility in CeO2-based nanocomposites. The lattice constants of the ceria nanocomposite also are contingent upon the attentiveness of hydroxide ions which primes to better morphology at low temperatures and pressure. XRD pattern of YCeO shows the Cubic structure of space group Fm3m having density 6.74gmcm^-3, volume 157.81*10⁶pm³, crystallite size 18.66nm and lattice strain is 0.0041 and many more structural parameters were calculated. FE-SEM and AFM studies show the granular structure and surface roughness. Surface porosity and specific surface area were observed by BET, average nanoparticle size was analyzed by the analyzer, and optical properties were observed by FTIR and showing various chemical groups and UV-Visible with band gap 3.27eV and absorbance at 256.58nm lastly thermal stability of this nanoparticle was analyzed by TGA.

Self-sensing cementitious composites include the use of conductive materials which have important capabilities in monitoring structure’s health. Graphene has been widely used to modify cementitious composites to get self-sensing properties due to its unique electrical properties along with its exceptional specific surface area, high aspect ratio, and high strength and modulus. The development of a cost-effective graphene-based cement material with uniform dispersion of graphene in the cement matrix remains challenging. Graphene aggregation in the cement matrix is considered as a ‘defect’, undermining the reinforcing effect of graphene and potentially affecting the performance of cementitious composites. Rather than employing the traditional approach of directly incorporating graphene into the cement matrix in the development of smart sensing composites, researchers used more efficient approach via nano-surface engineering of the sand. This paper reviews the current state of research on graphene-coated sand, particularly the progress made in the recent years. The purpose of this review is to summarize the results of those recent experiments. When graphene coated sand is added to the cementitious mix, the nano and micro-scale properties of graphene-sand incorporated cementitious composite are enhanced significantly, especially in terms of fresh properties, piezoresistive and mechanical properties and microstructures. However, more research is needed on graphene coated sand incorporated cementitious composite because it may provide a better reinforcement while also lowering its cost. Therefore, this review will encourage future researchers and civil engineers to develop functional graphene-based concrete for the next generation of smart infrastructure.