The propagation length of surface plasmon polaritons (SPPs) is investigated experimentally using a 1D metallic grating fabricated on a higher refractive index substrate (Gallium Phosphide, GaP). The ...experimentally measured value propagation length of the SPP (LSPP) at 785 nm wavelength is 13.33 ± 0.13 μm, which is close to the theoretical value of the LSPP on an ideal Au-thin film. The SPP resonance observed in far-field measurements confirms the underlying process and the related effects on the LSPP measured by scanning near field optical microscope (SNOM). Far-field measurements shows that LSPP is associated with the full width at half maximum (FWHM) of the SPP resonance which in-turn associated with in-plane directional scattering of the SPP.
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•Higher refractive index substrate is used.•Excitation and propagation length of the SPP is correlated with near- and far-field analysis.•Application in heat assisted magnetic recording.•Experimental work.
In this study, rGO/BiVO
4
nanospheres and cubics were effectively synthesized using hydrothermal technique (with varied concentrations ranging from 0.5 to 2.5 wt%) to design a heterostructure ...photocatalysts. Ultraviolet visible absorption spectroscopy, photoluminescence (PL) spectroscopy, X-ray diffraction (XRD) spectroscopy, scanning electron microscope (SEM), and Fourier Transform infrared (FTIR) spectroscopy were used to investigate the optical properties, structural, morphological, bending and stretching vibrations of functional groups of heterostructure composites. Ultraviolet spectroscopy was used to measure the band gap energy of pure BiVO
4
and rGO/BiVO
4
(2.40–2.31 eV). Under visible photo-illumination (420 nm), the photocatalytic performance of methylene blue (MB & RhB) dyes degradation was studied. Among all samples, the 2.5% rGO/BiVO4 photocatalyst demonstrated the highest photocatalytic activity. Rate constant of pure BiVO
4
spherical nanoparticles was also calculated by using simulation (COMSOL 5.3a) which was 0.00464 min
−1
as compared to experimental value 0.00656 min
−1
for MB and 0.00869 min
−1
as compared to experimental value 0.0079 min
−1
for RhB. The photocatalysis of MB and RhB dyes for five consecutive cycles demonstrated good recyclability, confirming the composite's reusability.
Graphical abstract
This study investigates the relationship between energy use and economic growth by incorporating financial development, international trade and capital as important factors of production function in ...case of China over the period of 1971–2011. The ARDL bounds testing approach to cointegration was applied to examine long run relationship among the series while stationarity properties of the variables was tested by applying structural break test.
Our empirical evidence confirmed long run relationship among the variables. The results showed that energy use, financial development, capital, exports, imports and international trade have positive impact on economic growth. The Granger causality analysis revealed that unidirectional causal relationship running from energy use to economic growth. Financial development and energy use Granger cause each other. There is bidirectional causality between international trade and energy use. The feedback relation exists between financial development and international trade. There is also bidirectional causality exists between capital and energy demand, financial development and economic growth and, international trade and economic growth. This paper makes significant contribution in energy economics and opens up new direction for policy makers to explore new and alternative sources of energy which would be helpful in meeting the rising demand of energy due to sustained rate of economic growth.
•Energy consumption, financial development, capital, exports, imports and international trade add in economic growth.•Energy consumption Granger causes economic growth.•Financial development and energy consumption Granger cause each other.•There is bidirectional causality between trade and energy consumption.•The feedback relation exists between financial development and international trade.
This study reports the simple synthesis of pure and Ag doped ZnO NPs with different doping concentrations of Ag (0.5%, 1%, 1.5% and 2%) for exploring photocatalytic performance and improving shelf ...life of fruits. The experimental (UV/Vis) and theoretical (COMSOL simulation) analysis reveals that synthesized ZnO nanoparticles exhibit band gap of 3.29 eV. The XRD, SEM, EDX, PL and FTIR techniques were used to reveal morphological, structural and optical properties of synthesized particles. The nanoparticles were used to check the photoctatlytic activity on methylene blue (MB) which reveals the fact that doping of silver (Ag) into ZnO enhanced photocatalytic performance while degrading the methylene blue. Moreover, synthesized nanoparticles applied on the fruit (peach) and investigated the shelf life with various factors as percent weight loss, ash content, moisture content, ascorbic acid, titratable acidity and total soluble solids contents. Experimental results are well correlated with the simulation results where lateral analysis technique helped us to explore and understand the underlying science associated with the concerned phenomenon. This study will have revolutionary impact for its application in improving the shelf life of the fruits which is direly needed to cater the food consumption quite efficiently.
Organic–inorganic halide perovskites are making breakthroughs in a range of optoelectronic devices. Reports of >23% certified power conversion efficiency in photovoltaic devices, external quantum ...efficiency >21% in light‐emitting diodes (LEDs), continuous‐wave lasing and ultralow lasing thresholds in optically pumped lasers, and detectivity in photodetectors on a par with commercial GaAs rivals are being witnessed, making them the fastest ever emerging material technology. Still, questions on their toxicity and long‐term stability raise concerns toward their market entry. The intrinsic instability in these materials arises due to the organic cation, typically the volatile methylamine (MA), which contributes to hysteresis in the current–voltage characteristics and ion migration. Alternative inorganic substitutes to MA, such as cesium, and large organic cations that lead to a layered structure, enhance structural as well as device operational stability. These perovskites also provide a high exciton binding energy that is a prerequisite to enhance radiative emission yield in LEDs. The incorporation of inorganic and layered perovskites, in the form of polycrystalline films or as single‐crystalline nanostructure morphologies, is now leading to the demonstration of stable devices with excellent performance parameters. Herein, key developments made in various optoelectronic devices using these perovskites are summarized and an outlook toward stable yet efficient devices is presented.
Inorganic and layered perovskites have broadened research paradigm for a range of optoelectronic devices. Their unique electronic and photophysical properties show that they are an excellent material, leading forefronts of solar cells, light‐emitting diodes, photodetectors, lasers, and beyond. An overview of key research activities for these devices is provided and challenges for their future research are identified.
Anti-bacterial activity of biologically synthesized zinc oxide (ZnO) nanostructures has engrossed great attention around the globe due to distinctive nanotechnological applications. Biogenic ZnO ...nanostructures have prominent anti-bacterial properties as compared to bulk because small sized nanostructures exhibit larger surface area leading to improved particle surface-reactivity. This study reveals that biologically synthesized ZnO nanostructures are bio-compatible, stable and have longer shelf life due to presence of phytochemicals which acts as stabilizing and capping agents during synthesis process. The anti-bacterial mechanism of ZnO nanostructures includes production of reactive oxygen species (ROS) such as hydrogen peroxide H
2
O
2
, OH
−
and O
2
−2
. The ROS provides major toxicity mechanism which includes destruction of cell wall due to interaction of ZnO nanostructures. Sometimes, ZnO nanostructures have increased anti-bacterial activity due to surface imperfections and ROS generation in dark. Interaction between ZnO nanostructures and bacterial cell causes mitochondrial weakness, intra-cellular outflow, and oxidative stress which eventually inhibits bacterial growth and kills the whole cell. This review describes anti-bacterial activity of biologically synthesized ZnO nanostructures by previously reported literature and tests used to examine anti-bacterial activity, influence of UV illumination, ZnO unique features i.e. size, concentration, morphology, and defects. Furthermore, it also presents significant anti-bacterial applications of ZnO nanostructures particularly in food packaging industry, pharmaceutical industry and other health care applications.
The novel Cd doped MoS
2
nanoparticles were synthesized through hydrothermal method using urea surfactant. The crystal structure and morphological analysis of synthesized materials were studied by ...X-ray diffraction (XRD) and scanning electron microscope (SEM). Optical properties of prepared samples were observed through ultraviolet visible (UV–Vis) spectroscopy while recombination time of photo generated charge carriers was measured using photoluminescence (PL) spectroscopy. Functional groups present in fabricated MoS
2
nanostructures were examined with the help of Fourier transform infrared (FTIR) spectra. Photocatalytic efficiency of Cd doped MoS
2
nanosheets was evaluated through degradation of methylene blue and rhodamine B dyes in aqueous medium under visible light irradiation for 180 min. The stabilities and scavenger effect of prepared MoS
2
nanoparticles were also observed in 05 cycles of repeated experiments and using different scavenger materials. Moreover, theoretical modeling was also designed on the basis of experimental conditions in COMSOL 5.3a software version to calculate the rate constants for 2D models of MoS
2
and found negligible difference in experimental values due to symmetry, asymmetric boundaries of built model. Experimental values of rate constant for MB is maximum (0.00551/min) as compared to RhB dye which possessing 0.00548/min. It was also found that 5% Cd doped MoS
2
nanosheets were optimal materials among all other prepared samples having 96% and 94% photocatalytic efficiency for MB and rhodamine B dyes respectively which is associated with lowest band gap and recombination time.
Different photo-thermal agents such as gold nanostructures with various shapes and sizes including nano-rods, nano-cages, nano-shells exhibit tunable optical properties, surface chemistry, resonance ...frequency and non-toxicity. Furthermore, gold nanoparticles (Au NPs) also utilized for diagnosis purposes and drug carriers for thermo-therapy of biological cells targets and potential bio-medical applications against various cancer treatments. To control complications of conventional cancer therapeutics, Stimuli-assisted drug delivery systems (DDS) together with interior and exterior Stimuli-assisted prompts have received particular interest by the scientific community around the globe. Among both of them, external stimuli-responsive parameters provide more controlled DDSs that circumvent individual discrepancy. Many researchers reported that light-responsive DDSs manifest interesting features because of proficiency and preferable spatiotemporal control. Among them, near-infrared light-responsive DDSs are potential candidates that follow various mechanisms such as photo-thermal effect, two photon absorption, and up converting nano-particles. This review presents an over view of different morphologies of Au nanostructures boosting the efficiency of DDSs by utilizing the phenomenon of surface plasmon resonance by overcoming the major challenges.
Quorum quenching (QQ) has been recognized as an emerging anti-biofouling strategy for membrane bioreactors (MBRs), but studies on effective QQ bacterial doses are needed. Therefore, in this study, ...the QQ efficacy for sheet-type media containing different amounts of QQ bacteria (i.e., Rhodococcus sp. BH4) with respect to biofouling control during MBR treatment of synthetic and real municipal wastewaters was investigated. The QQ sheets with well-embedded BH4 bacteria were distinctly effective at alleviating biofouling, but their efficacy was highly dependent on the QQ bacterial dose. The activity of the QQ sheet increased with the QQ bacterial density and its pseudo-first order rate constant reached 3.52 h−1 with 100 mg BH4 per liter of reactor volume. No QQ activity loss occurred with long-term use of the QQ sheets. The relationship between QQ dose and fouling delay had a strong, linear correlation. Fouling retardation was more pronounced with real wastewater because it had less biofouling propensity owing to its inferior organics and nutrients. In fact, the MBRs fed with real wastewater experienced a dramatic decrease in extracellular polymeric substance (EPS) content responsible for biofouling. QQ suppressed the EPS secretion leading to fouling mitigation, but with no impact on biological treatment performances.
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•Quorum quenching (QQ) bacteria doses on biofouling control were investigated.•The degree of fouling mitigation was directly proportional to the QQ bacterial dose.•QQ effects were more prominent with real wastewater due to less exopolymer production.•Long-term use (>100 d) of QQ sheets for synthetic and real wastewater was possible.•No QQ activity loss nor negative impact to biological treatment occurred.
This study reports the simple synthesis of pure and La-doped (1, 2, 3, 4 and 5%) WO
3
nanoparticles (NPs) for the degradation of MB dye. The UV–Vis, XRD, FTIR, SEM and PL techniques have been ...utilized for the evaluation of prepared samples. The photo catalytic activity of these synthesized samples has been observed for the degradation of methylene blue (MB) in the presence of visible light via photo catalysts (WO
3
, La-WO
3
) NPs. Additionally, the suppression of the band gap from 2.81 to 2.23 eV along photo generated electron–hole pair has been demonstrated by UV visible and PL spectroscopy respectively. The crystalline size of 4% La-WO
3
, reduced from 30 to 11 nm as compared to pure WO
3
. FTIR spectroscopy analysis reveals the synthesized material is composed of tungsten and oxygen. However, in the presence of visible light, the optimal 4% La-doped WO
3
NPs’ are capable of degrade methylene blue (MB) to 94% within 180 min. To test the stability of the optimized catalyst, reusability and trapping tests have been conducted. The correlation between the theoretical model and the experiments has also been performed using the COMSOL Multiphysics module 5.3a.
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