Trap-level-tunable Se doped CdS quantum dots with excellent hydrogen evolution performance without co-catalyst

Recently, nanotechnology has emerged as a tool for the development in the biological synthesis of noble metal nanoparticles. Among other conventional synthesis methods, biological synthesis methods...

Green synthesis of silver nanoparticles by using various extracts: a review

Within the framework of this study, the effect of nanoparticles of the essential trace element selenium stabilized by Polyvinylpirrolidone (PVP) C15 (8 ± 2 kDa) and ascorbic acid on the germination of barley seeds has been studied. Selenium nanoparticles stabilized by PVP C15 (8 ± 2 kDa) and ascorbic acid, characterized by a spherical shape, monodisperse size distribution, and a diameter of about 70 ± 5 nm, were obtained by the chemical reduction method. The experiment compared the effect of selenium nanoparticles and selenous acid on seed germination. The positive effect of preparation of selenium nanoparticles stabilized by PVP C15 (8 ± 2 kDa) and ascorbic acid on the length of roots and shoots, the number of roots, and the percentage of seed germination has been revealed. It was determined that the highest percentage of Hordeum vulgare L. culture seed germination was achieved using a preparation of selenium nanoparticles stabilized by PVP C15 (8 ± 2 kDa) and ascorbic acid at a concentration of of 4.65 µg/mL. Analysis of the results showed that selenium in the form of nanoparticles has an order of magnitude that is less toxic than in the form of selenous acid. The study of morphological and functional parameters during the germination of Hordeum vulgare L. seeds allowed us to conclude that selenium nanoparticles can be successfully used in agronomy and agriculture to provide plants with the essential microelement selenium, which is necessary for the normal growth and development of crops.

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Effect of Selenium Nanoparticles on Germination of Hordéum Vulgáre Barley Seeds

Utilization of efficient nanomaterials in perovskite solar cells (PSCs) for effectual conversion of solar energy to electrical energy has prompted the extensive progression of PSCs as a suitable al...

Interfacial engineering revolutionizers: perovskite nanocrystals and quantum dots accentuated performance enhancement in perovskite solar cells

Synthesis, characterization and electrochemical investigation of physical vapor deposited barium sulphide doped iron sulphide dithiocarbamate thin films

Synthesis and characterization of metal sulphide nanoparticles to investigate the effect of nanoparticles on germination of soybean and wheat seeds

Gas-sensor reported here consist of a sensing chip of a metallic grating designed on gold (Au) film over a glass substrate which has been modelled using finite element analysis (FEA). The Au is layered in the form of horizontal nano-strips with a periodic nano-sized gap known as slit-width. The transverse magnetic (TM) light illuminates the metallic films from substrate side at normal incidence. The transmission loss spectrums have been extracted for 0th order diffraction for different physical interpretations. The several combinations of periodicity and slit width have been optimized by taking slit width as half of periodicity. The refractive index sensitivity achieved at optimal geometrical parameters is noteworthy and it is reported to be 599 (nm/RIU) at a spatial period of 660 nm. The novel theoretical results has been supported by far field and near field analysis. The design suggested in this report is important becuase of the wavelength range that lie in the visible region where most of the real life spectrometers works. Such sensors can be applicable in industries for detection of toxic gases and harmful metallic pieces in atmosphere.

Modeling of 1D Au plasmonic grating as efficient gas sensor

A simulation study for the opening of plasmonic bandgap (PBG) with control over it by varying the slit width (SW) for exposed and buried 1D metallic gratings has been reported by using COMSOL Multiphysics, RF module. We observe excitation of surface plasmon polaritons (SPPs) and splitting up of surface plasmon resonance (SPR) dip to induce PBG by keeping the periodicity constant and varying the slit width for each grating. The resonance wavelengths are taken through far-field transmission and reflection spectra of exposed and buried gratings of different slit widths respectively. The new trends of bandgap energy for varying slit width of exposed and buried metallic gratings have been reported and discussed. In each trend, range of optimum value of slit widths are obtained around half of the periodicity which is a significant observation. The comparison of PBG energy for different metallic devices and the opening of PBG in the dispersion curves is also presented by the variation of incident angles. The potential applications of these devices are to control the surface-enhanced Raman scattering (SERs), light-emitting diodes (LEDs), and solar cell applications.

Investigation of Plasmonic Bandgap for 1D Exposed and Buried Metallic Gratings

This paper investigates the behavior of the surface plasmon polaritons (SPPs) on dielectric-metal interface using Ag thin film on glass substrate. The Kretschman configuration, which is sensitive to the change in the local environment adjacent to Ag thin film, has been modeled using COMSOL Multiphysics, RF module. The graphical presentation for the change in excitation spectra of SPPs on the interface has been analyzed by adjusting the incident angle greater than critical angle of glass while keeping the thickness of Ag thin film constant. The cross-sectional view reveals that the maximum amplitude of electric field occurs at 43° incidence. In order to study the behavior of resonance dip at varying refractive index (from 1.00 to 1.01), the reflection spectra for transverse magnetic (TM) mode of incident light has been extracted using far-field analysis. To further explore the sensitivity and resolution of the device, nm/RIU is collected by using the change in the wavelength (nm) of SPPs for minimum reflection. The remarkably maximum sensitivity of the device has been calculated as 23,000 nm/RI and Q value calculated for Ag-based sensing is 13.

Optimizing the Sensing Efficiency of Plasmonic Based Gas Sensor

This study presents the design and optimization of device with 1D nanostructured grating modeled on gold (Au), silver (Ag) and copper (Cu) for sensing a minor variation in refractive index (RI). This small change in the adjacent media to metallic grating is detected quite effectively using the unique characteristic of the surface plasmon polaritons (SPPs). The electric field (E-field) of the SPPs penetrates into the nearby media which is very sensitive to slight change in RI. The grating devices has been simulated by using COMSOL Multiphysics 5.3a with periodicity 700 nm, film thickness 50 nm and optimum slit width 300 nm in correspondence with fundamental plasmonic mode. The 0th order transmission spectra have been extracted from each grating device by illuminating (through the substrate side) with p-polarized light at normal incidence. The change in RI of analyte studied to have a significant effect on the resonance wavelength. The sensitivity has been calculated as 700, 731 and 722 nm/RIU for Au, Ag and Cu grating devices respectively which is remarkable. The stability and quick sensing of Au-device make it suitable for application besides some other deficiencies (e.g. slightly less sensitivity as compared to Ag) which should be compromised. Near field analysis has been performed to apprehend the underlying physics connected with each resonance. The highest value of electric and magnetic fields (E-field and H-field) are obtained in the case of Au grating indicating the most efficient excitation of SPPs. This confirms the reasoning behind the efficient sensitivity of Au grating device and finds applications in medicine.

Tahir Iqbal

Papers

Synthesis and characterization of metal sulphide nanoparticles to investigate the effect of nanoparticles on germination of soybean and wheat seeds

Modeling of 1D Au plasmonic grating as efficient gas sensor

Investigation of Plasmonic Bandgap for 1D Exposed and Buried Metallic Gratings

Optimizing the Sensing Efficiency of Plasmonic Based Gas Sensor

Surface plasmon based 1D-grating device for efficient sensing using noble metals