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In this work, we demonstrate the use of annealed sol-gel derived ZnO nanoparticles acting as electron transport layer (ETL) in inverted bulk heterojunction (BHJ) polymer solar cells (PSCs). We have examined the photovoltaic performance of devices based on poly(2-methoxy-5-(2-ethylhexyloxy)- p -phenylenevinylene) (MEH-PPV):(6,6)-phenyl-C61-butyric acid methyl ester (PC 61 BM) blend system employing the ZnO nanoparticles as an ETL with CuI as hole transport layer (HTL) in comparison to the case of using the conventional HTL of poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonate) sulfonic acid (PEDOT:PSS). The effect of the presence of another layer of ZnO macrospheres attached to the ZnO nanoparticles is also investigated. The highest power conversion efficiency (PCE) value of 1.35% was achieved for device: ITO/ZnO nanoparticles/MEH-PPV:PC 61 BM/CuI/Ag, which is 275% more the value obtained when CuI was replaced by PEDOT:PSS. The comprehensive analyses on structural and optical characteristics including SEM, XRD, FTIR, PL and UV–vis spectroscopy indicated that the use of the ZnO nanoparticles alone as ETL, together with the CuI as HTL could effectively reduce trap-assisted recombination and charge accumulation at the interface, which is beneficial for the enhanced device performance.

The development and designing of self-testing blood-glucose electrochemical biosensor is an effective approach for diabetic patients to overcome and control this high health concerning issue. Herein, we successfully designed novel single-walled carbon nanotubes-porous silicon nanocomposites framework (SWCNTs-PSi NCs) via simple stain etching and ultrasonication techniques. X-ray Diffraction (XRD), Raman spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy (TEM), Energy-Dispersive Spectroscopy (EDS), and X-ray Photoelectron Spectroscopy (XPS) were employed to study the porous morphology with ~30 nm pore size and overall structural characterization of the SWCNTs-PSi NCs. This newly fabricated SWCNTs-PSi modified glassy carbon electrode (GCE) biosensor can measure an extremely wide range of glucose (0.5–28.5 mM) in phosphate buffer solution (PBS) compared to the regular glucose concentration level in human blood serum (3.9–7.1 mM) with a sensitivity 0.0614 μAmM−1 cm−2 and detection limit 9.6 ± 0.1 μM. This non-enzymatic glucose biosensor demonstrated excellent selectivity during the investigation of the possible impact of common interfering substances that are present in human blood. This proposed non-enzymatic glucose biosensor has also been tested for real human blood serum analysis to determine blood glucose levels showing highly motivated results. The newly designed SWCNTs-PSi/GCE biosensor exhibits excellent reproducibility and repeatability, along with long-term stability.

The combination of inorganic semiconductor metal oxides and organic conducting polymers is a favorable strategy in fabricating electrochemical sensors due to their outstanding electrocatalytic performance. Herein, a novel electrochemical sensor for detection of liquid methanol is fabricated using a modified glassy carbon electrode (GCE) with Nafion binder. The active sensing material is composed of a conductive polythiophene (PTh) doped iron oxide (α-Fe2O3) that simply synthesized by a facile sol-gel route in presence of a structure directing agent F127 followed by an oxidative polymerization process. Cyclic voltammetry and electrochemical impedance measurements revealed enhanced electrocatalytic response at the PTh/α-Fe2O3/Nafion modified GCE compared to either α-Fe2O3/GCE or bare GCE with a diffusion-controlled kinetics in ferro/ferricyanide redox couple. Material characterization using various analytical techniques confirmed the formation of PTh sheets onto highly crystalline rhombohedral structure of α-Fe2O3 with distinctly lattice fringes 0.37 nm. Outstanding sensing parameters are achieved with a sensor sensitivity of 0.793 μAmM−1cm−2, limit of detection LOD at (S/N = 3) = 1.59 mM, a wide range of methanol concentration from 5 to 1000 mM with a correlation coefficient R2 = 0.9483. Furthermore, the current proposed sensor electrode showed adequate operational stability and acceptable reproducibility and repeatability.

Photoluminescence and UV–Vis spectral evaluation of a poly allyl diglycol carbonate (CR-39) detector coated by poly(2-methoxy-5-(2-ethyl-hexyloxy)-1,4-phenylene-vinylene) (MEH-PPV) conducting polymer are demonstrated. The CR-39 surfaces were exposed to thin 241Am disk source that emits alpha particles with activity 333 kBq. Surface modification of the detector by MEH-PPV was acquired by a simple dip coating process. Our findings revealed that the spectroscopic analysis using FTIR is insensitive approach to detect the induced modifications in the irradiated samples. Additionally, the track density of the irradiated samples affects significantly the photoluminescence and UV–Vis responses of the CR-39 samples. The spectral peak heights and the integrated intensities under the peaks exhibit linear correlations (correlation coefficient R2 = 0.9904 to 0.9968) with the fluence of alpha particles. The linear fitting functions together with the corresponding fitting parameters were evaluated. Both techniques exhibited remarkable spectral differences for the irradiated samples, and hence they could be employed to provide sensitive methods for alpha particle detection. Results of sample fabrication and modification, along with structural and optical evaluation are addressed and thoroughly discussed.

Silver nanoparticles (AgNPs) have been reduced onto porous silicon (PSi) surface in a simple immersion plating bath. Here, PSi with average pore size of ∼30 nm was used as both a mechanical support and a mild reducing agent. AgNPs-meso-PSi hybrid structures exhibit a highly sensitive and reproducible surface-enhanced Raman scattering (SERS) response. A detectable concentration as low as 100 pM of crystal violet has been achieved with an enhancement factor (EF) of 1.3 × 10 6 . No aging effect was observed for the current substrates after storing in air for three weeks. The large EF is essentially attributed to a combination of electromagnetic enhancement and charge transfer mechanism.

A capacitive sensor based on porous silicon (PSi) for detection of various polar (ethanol, methanol, acetone, acetonitrile, chloroform) and non-polar organic solvents (n-hexane, toluene) was described. The meso-PSi layer with an average pore size of 30 nm was prepared by a galvanostatic electrochemical etching of crystalline silicon in HF-based solution. Surface passivation was conducted by anodic oxidation process and the electrical contacts were made exclusively onto the front porous structure. The as-fabricated sensor exhibits highly sensitive and reversible response toward polar organic molecules during the real-time measurements of capacitance, whereas the capacitive sensing behavior was irreversible and opposite in direction in case of non-polar solvents. The response time was in the order of acetone

The synthesis and surface properties of a composite material consisting of porous silicon/magnetite nanoparticles (PSi/Fe3O4 NPs) are demonstrated. PSi layers with intermediate pore size (∼100 nm) are prepared by electrochemical porosification of n-type Si wafer in a hydrofluoric acid-containing oxidizing agent and surfactant. The intrinsically luminescent PSi templates are infiltrated with ferromagnetic Fe3O4 NPs grown by a simple hydrothermal approach with average sizes ranging from 8 to 30 nm. The photoluminescence intensity of magnetic nanocomposite was enhanced after Fe3O4 loading, probably due to the recombination of photoexcited carriers within the nanocrystallites. Magnetization measurement for the nanocomposites indicated that the magnetic nanoparticles retain their ferromagnetic characteristic at room temperature. The nanocomposites have been characterized by various techniques including, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) and magnetic measurements. The biocompatibility of both components and the ability to tailor the magnetic properties of the composite might be useful for magnetic and biomedical applications.

A nanostructured CoPt magnetic film was deposited from a single electrolyte into porous silicon layer by an electrochemical technique, followed by annealing at 600 °C in Ar atmosphere during which the CoPt alloy was converted to L10 ordered phase. Porous silicon with pore diameter between 5 and 100 nm was firstly fabricated by galvanostatic anodization of n-type silicon wafer in the presence of CrO3 as oxidizing agent and ethanol or sodium lauryl sulfate as surfactants. The role of the surfactant on the produced pore size and morphology was investigated by means of UV–vis spectra. As-formed porous silicon was consequently used as a template for the electrodeposition of magnetic CoPt film. The phase formation, microstructure and the magnetic properties were fully analyzed by XRD, FE-SEM, EDS and VSM measurements. It was found that, upon annealing the coercivity was significantly increased due to the transformation to the L10 ordered structure. The saturation magnetization and remanence ratio were also found to increase, indicating no loss of Co content or oxidation reaction after the annealing. Results of synthesis and characterization of CoPt/porous silicon nanocomposite are addressed and thoroughly discussed.