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In this work, we report the preparation of nanostructured electrodes based on dense arrays of vertically-aligned copper (Cu) nanowires (NWs) to be subsequently covered by cadmium telluride (CdTe) thin films, with great potential to be used within “substrate”-type photovoltaic cells based on AII-BVI heterojunctions. In particular, the multi-step preparation protocol presented here involves an electrochemical synthesis procedure within a supported anodic aluminum oxide (AAO) nanoporous template for first generating a homogeneous array of vertically-aligned Cu NWs, which are then further embedded within a compact CdTe thin film. In a second stage, we tested three deposition methods (vacuum thermal evaporation, VTE; radio-frequency magnetron sputtering, RF-MS; and electrochemical deposition, ECD) for use in obtaining CdTe layers potentially able to consistently penetrate the previously prepared Cu NWs array. A comparative analysis was performed to critically evaluate the morphological, optical, and structural properties of the deposited CdTe films. The presented results demonstrate that under optimized processing conditions, the ECD approach could potentially allow the cost-effective fabrication of absorber layer/collecting electrode CdTe/Cu nanostructured interfaces that could improve charge collection mechanisms, which in turn could allow the fabrication of more efficient solar cells based on AII-BVI semiconducting compounds.

In this work, we report results on the fabrication and characterization of a surface plasmon resonance (SPR) pH sensor using platinum (Pt) and polyaniline (PANI) layers successively coated over an unclad core of an optical fiber (FO). The plasmonic thin Pt layer was deposited using a magnetron sputtering technique, while the pH-sensitive PANI layer was synthesized using an electroless polymerization method. Moreover, the formation of PANI film was confirmed by X-ray photoelectron spectroscopy (XPS) technique and its surface morphology was investigated using scanning electron microscopy (SEM). It was found that the PANI/Pt-coated FO-SPR pH sensor exhibits a fast and linear response in either acid or alkali solutions (pH operational range: 1 to 14). The proposed FO-SPR sensor could be used for biomedical applications, environmental monitoring or any remote, real-time on-site measurements

Tin‐based nanowire electrodes present desirable properties as lithium‐ion battery anodes, because they undergo volume changes without pulverization. However, they suffer from limited mass loading and propensity for surface parasitic reactions. Herein, we evaluate the electrochemical performances of interconnected nickel‐tin nanowire network electrodes (NiSn 3DNWN) with nanowire diameters of 40 nm, 105 nm, and 230 nm, respectively, that attain mass loadings of up to 3 mg cm‐2. To mitigate the surface parasitic reactions, the effects of fluoroethylene carbonate (FEC) and vinylene carbonate (VC) additives are investigated as a function of nanowire diameter and additive concentration. The results show that FEC and VC of all compositions improve the capacity retentions and coulombic efficiencies of the NiSn 3DNWN electrodes. In 10 vol% FEC, the electrodes demonstrate a similar capacity of ∽ 550 mAh g‐1, but the capacity retentions after 100 cycles are 73.68%, 53.79%, 51.70% for the 40 nm, 105 nm, and 230 nm NiSn 3DNWN, respectively. However, the 105 nm‐diameter nanowire electrode has the highest average coulombic efficiency of 96.55%. Electrochemical impedance spectroscopy and post‐cycling investigations reveal that FEC has the most profound effect on the interphasial resistances, which is reflected in the rate performances of the tested electrodes. This article is protected by copyright. All rights reserved.

The paper reports for the first time an innovative polyaniline (PANI)/platinum (Pt)-coated fiber optic-surface plasmon resonance (FO-SPR) sensor used for highly-sensitive 4-nitrophenol (4-NP) pollutant detection. The Pt thin film was coated over an unclad core of an optical fiber (FO) using a DC magnetron sputtering technique, while the 4-NP responsive PANI layer was synthetized using a cost-effective electroless polymerization method. The presence of the electrolessly-grown PANI on the Pt-coated FO was observed by field-emission scanning electron microscopy and subsequently evidenced by energy dispersive X-ray analysis. These FO-SPR sensors with a demonstrated bulk sensitivity of 1515 nm/RIU were then employed for 4-NP sensing, exhibiting an excellent limit-of-detection (LOD) in the low picomolar range (0.34 pM). The proposed sensor's configuration has many other advantages, such as low-cost production, small size, immunity to electromagnetic interferences, remote sensing capability, and moreover, can be operated as a "stand-alone device", making it thus well-suited for applications such as "on-site" screening of extremely low-level trace pollutants.

The active layer of the bulk heterojunction organic photovoltaic cells is typically based on a polymeric blend containing a donor polymer and a fullerene-based polymer electron acceptor. However, in the last decade non-fullerene polymer-based solar cells have seen a rapid progress, due to their extraordinary chemical, thermal and photo stability, and because of their ability to decrease the voltage loss. The conventional Organic Photovoltaic Cells (OPVs), structures based on either P3HT:PCBM bulk heterojunction (BHJ) polymeric blend or P3HT/PCBM bilayer heterojunction, have limited efficiency and stability, in principal due to the fullerene derivatives used as acceptor component. PCBM for example, as many other fullerene derivatives, exhibits some deficiencies, such as: limited chemical and energetic tunability, small range of absorption spectra, morphological instability and relatively high production costs. That is why in the last years, novel non-fullerene materials started to be used in order to overcome the above limits associated with the fullerene acceptors. In this paper two different non-fullerene acceptor materials have been tested as potential candidates for the efficient OPVs based on P3HT donor polymer as main absorber: a new conjugated polymer containing chelating ligands like 1,10-Phenanthroline (Phen), and a small-molecule acceptor like 5,10,15,20-Tetra(4-pyridyl)-21H,23H-porphine (TPyP). For both cell configurations a decrease of the voltage loss was obtained, and it was also observed that the thickness of the P3HT donor layer has an important contribution to the output power (Pmax) and fill factor (FF) of the OPV structures (FF and Pmax increased almost two times by decreasing the thickness of the P3HT donor layer).

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We reported an efficient way of preparing large and dense ferromagnetic arrays of vertically-aligned Ni nanotubes (NTs). The synthesis method allowed then for a direct, effective and controllable thermal conversion of the as-prepared Ni NTs into heterostructured Ni/NiO NTs, without compromising the nanostructures' verticality to the substrate and their initial tubular integrity. Next, we demonstrated the ability to tune the dipolar interaction field (DIF) in this array of one-dimensional (1D) Ni/NiO heterostructures, just by slightly changing the thickness of the antiferromagnetic NiO layer. Furthermore, the proposed fabrication method assures full compatibility with the standard Si processing, providing thus a direct pathway towards large-scale integrability and manufacturing of a new generation of magnetic devices relying on dense arrays of vertical 1D magnetic nanostructures.

A new strategy to elaborate (1-3) type multiferroic nanocomposites with controlled dimensions and vertical alignment is presented. The process involves a supported nanoporous alumina layer as a template for growth of free-standing and vertically aligned CoFe2 nanopillars using a room temperature pulsed electrodeposition process. Ba0.70Sr0.30TiO3–CoFe2O4 multiferroic nanocomposites were grown through direct deposition of Ba0.7Sr0.3TiO3 films by radiofrequency sputtering on the top surface of the pillar structure, with in situ simultaneous oxidation of CoFe2 nanopillars. The vertically aligned multiferroic nanocomposites were characterized using various techniques for their structural and physical properties. The large interfacial area between the ferrimagnetic and ferroelectric phases leads to a magnetoelectric voltage coefficient as large as ∼320 mV cm−1 Oe−1 at room temperature, reaching the highest values reported so far for vertically architectured nanocomposite systems. This simple method has great potential for large-scale synthesis of many other hybrid vertically aligned multiferroic heterostructures.

We report a simple and reliable route for the synthesis of threedimensional bicontinuous Ni–NiO core–shell nanowire networks. The interconnected architecture is self-supported and provides rapid ion and charge collection pathways, as well as efficiently accommodates the volume change induced stress resulting in enhanced lithium storage properties. The capacity per footprint area is 40 times higher than that of a 2D system at an equivalent active material thickness.

A major challenge in the development of efficient magnetoelectric nanocomposites is the adequate control of the interfaces, in order to avoid the formation of undesirable interphases and to ensure an optimal strain mediated coupling. In this work we used a combination of low-cost impregnation and electrodeposition processes within the ordered nanochannels of a porous anodic alumina template, to elaborate CoFe2O4–PbZr0.52Ti0.48O3 core/shell nanocable arrays with high interfacial areas between the ferroelectric and the magnetic phases. We have shown in this way that the thermal annealing steps required for phase's crystallization and oxidation of metallic CoFe2 into spinel CoFe2O4 are critical with respect to interdiffusion phenomena through the interfaces. The impact of the processing temperature on the morphological and structural features of the nanocables was then discussed. We demonstrated that an optimization of process variables in the synthesis of CoFe2O4–PbZr0.52Ti0.48O3 nanocables allows a significant improvement in their microstructure and ensures the chemical integrity of the two-phase materials, an important concern when seeking for enhanced multiferroic properties.