Metallic nanoparticles find tremendous applications in every field. The surface morphology of these metallic nanoparticles drives their properties and is usually regulated by their mode of synthesis. Apart from chemical and physical methods available for producing metallic nanoparticles, ‘plant-mediated synthesis’ is considered advantageous mainly because of its eco-friendly nature and cost-effectiveness. Plant-based materials have been successfully incorporated in food, pharmaceuticals as well as in tissue engineering applications. The secondary metabolites in plants are of prime importance as they play a major role as reducing agents. Therefore, numerous plants bearing diversified phytochemical profiles have been explored for the synthesis of metallic nanoparticles. The current review attempts to encompass available information about the synthesis and application of different metallic nanoparticles employing herbal extracts. Further, critical insights about the properties of metallic nanoparticles, their morphology, and anticipated applications (e.g. antimicrobial, anticancer, anti-diabetic, photo-catalytic, etc) with a futuristic approach are discussed.

Semiconductor mediated photocatalysis has emerged as a promising solution for dye degradation and environmental remediation. Zinc Indium Sulfide (ZnIn2S4, ZIS) is a benign, eco-friendly, visible-light-responsive photocatalyst, exhibiting excellent optoelectronic properties. In this work, we present a scalable, low temperature and template-free chemical aqueous solution method for the synthesis of ZIS. The obtained powder sample was used for a comparative dye degradation study of cationic (Malachite green) and anionic (Congo red) dye. The higher photocatalytic efficiency of ZIS is due to the higher BET surface area (55.042 m2 g−1) and low band gap (2.3 eV). Under Sunlight, almost 80 percent degradation occurs within 20 min of the experiment for both Malachite green (MG) and anionic Congo red (CR) dye, outperforming previously reported results. Scavenger studies were used to figure out the radicals involved in photocatalytic mechanics and to come up with viable photocatalytic degradation routes. The reusability and stability of ZIS were carried out up to the 5th cycles. Our result revealed that ZIS possesses high stability, reusability, and efficient potential to be an effective dye degradation photocatalyst.

We investigated incorporation of a novel approach of phosphorous silicate glass layer thinning (PGT) process in the N-PERT process flow to minimise pinhole defects at the silicon nitride (Si3N4) surface. The thinning (PGT) process for optimum HF deposition time of 12 min resulted in excellent cell efficiency of ∼20.55% with pinhole free layer and high electrical yield (∼0% for I Rev > 1.5 A). After optimising technology, stability is also explored with and without PGT process line, which confirms advantages of this approach. This significant reverse failure reduction due to the proposed PGT process can eventually help in improving overall cell performance of the N-PERT devices. This process can be a part of strategy for reducing process cost of solar cell in any industrial mass production line with improved yield (reduction in reverse failure from 6.6 to 1.5% for one month of mass production). Thus, the PGT process with negligible electrical rejection and high yield increases the possibility of high throughput in mass production line.

Synthetic dyes emerging from wastewater effluents result in a hazardous environment to our society, hence removal of these dye molecules from the water bodies is necessary due to their toxic nature for living beings. In our study, a straightforward one pot synthetic process is conducted to synthesize reduced graphene oxide (RGO) using Averrhoa carambola fruit extract. To confirm the formation of RGO, different characterization techniques such as Fourier transform infrared spectroscopy (FTIR), UV–Vis spectroscopy and X-Ray Diffraction (XRD) are investigated. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) are used to understand the morphology of RGO. Adsorption kinetics for pseudo-first order and pseudo-second order has been carried out for both dyes. Freundlich and Langmuir adsorption isotherm models were confirmed to describe each of the adsorption ability responses with high correlation coefficients. Maximum adsorption capacities of methylene blue (MB) and crystal violet (CV) on RGO were 52.308 mg g−1 and 31.466 mg g−1 respectively. The adsorption ability of this adsorbent is monitored by recyclability in five subsequent cycles and it is observed that up to 5 cycles, there is no significant decrease in adsorption capability. The present study showed that RGO is highly efficient in removing MB and CV dyes from environmental water bodies. The thermodynamics study for the adsorption phenomena of MB and CV dyes on RGO sheet has been investigated.

This study aims to develop a novel, simple, efficient, and low-cost method to prepare hierarchical porous carbon nanofiber derived from corn silks (CSAC) through a one-step carbonisation-physical activation process. The carbon precursors were activated by KOH solution at a high pyrolysis temperature to prepare activated porous carbon as an electrode material for supercapacitors without using binders. This study focused on the effect of different activation temperatures of 600, 700, 800, and 900 °C on the production of highly porous carbon nanofiber. An enhancement mechanism is proposed, which not only performed high nanofiber structures to possess the large specific active surface area to enhance energy density but also achieved micro-mesopore combination to realise fast ion-transport channels for boosting high power density. A maximum specific surface area of approximately 1096.95 m2 g−1 was achieved by CSAC7. Furthermore, the electrochemical performance was evaluated using 1 M H2SO4 solution as an electrolyte through a novel two-electrode binder-free system. The electrode materials produced a maximum specific capacitance of 237 F g−1 at a current density of 1 A g−1. These excellent characteristics show that the synthetic approach has a great potential for fabricating high-performance supercapacitors.

The pulsed laser ablation in liquid (PLAL) technique was used to successfully synthesise silver nanoparticles (Ag NPs). With the goal of controlling their size, a laser wavelength of 1064 nm was focused on the Ag bulk target immersed in distilled water in a glass vessel with different laser fluences. The effect of laser fluence, and thus Ag NPs concentration on the bacterial pathogenic was investigated. While the Fourier-transform infrared spectroscopy (FTIR) and x-ray diffraction (XRD) patterns confirm the presence of Ag NPs, UV–vis spectrophotometry revealed a significant absorption peak at around 405 nm, which is attributed to the obtained Ag NPs’ characteristic surface plasmon resonance (SPR) peak. The SPR peak shifted towards a shorter wavelength as the laser fluence was increased, indicating that the Ag NPs have reduced in size. The transmission electron microscopy and size distribution images of Ag NPs clearly showed the effects of laser fluence on size reduction of Ag NPs. Bacteria activity was effectively inhibited by the Ag NPs which are found to be more effective against Gram-negative (Escherichia coli) than Gram-positive strains (Streptococcus aureus). PLAL has proven to be an effective method for controlling the size of NPs, which can be used in a variety of applications.

Iron sand-based Fe3O4 nanoparticles–polyvinylidene fluoride (PVDF) nanofibers were processed inside an electrospinning system at room temperature. The incorporation of Fe3O4 nanoparticles into the PVDF matrix decreases the diameter of the fibers. The presence of the Fe3O4 crystalline phase in the electrospun PVDF-Fe3O4 fiber indicates the unchanged Fe3O4 crystal structure. The surface morphology of the samples was altered considerably after the electrospinning and heating processes. Infrared spectroscopy identification confirmed the PVDF α to β-phase transformation in the PVDF and PVDF-Fe3O4 fibers. The thermal analysis detected a higher residual mass of the PVDF-Fe3O4 sample than that of the pure PVDF at high temperatures. Through the hysteresis characteristics, a ferromagnetic behaviour was observed for all samples. The efficient and low-cost fabrication of the PVDF-Fe3O4 fibers could be considered practical for diverse applications of nanotechnology.

One of the most important criteria to design more than 30% efficient III–V compound/Si based dual junction solar cell is that we must design atleast 20% efficient III–V compound material top cell. In this regard, we designed a bandgap engineered GaAs0.95P0.05 single junction solar cell with reduced bandgap of (E g ) = 1.48 eV. Reducing the bandgap from 1.72 eV to 1.48 eV for GaAs0.95P0.05 cell leads to generate higher short circuit current, while having the tradeoff with the open circuit voltage. Due to small change in lattice constant of GaAs0.95P0.05 cell, some recombination is observed near the junction area. Although the minimal degradation is observed in open circuit voltage, the higher short circuit current drives the overall efficiency of the GaAs0.95P0.05 single junction solar cell. The designed solar cell provides an extended internal absorption for longer wavelength of spectrum. The high electron mobility of 8500 cm2 V–S−1 was observed with very high electron to hole mobility ratio of 21.25. The optimization of the cell is done using two back surface field layers (AlInP and AlGaInP) of higher bandgap material. The high short circuit current density of J SC = 25.93 mA cm−2 with V OC = 1.1635 V achieved by the designed cell with the highest efficiency of η = 25%. The solar cell is irradiated under 1-Sun solar irradiation in the AM1.5 G environment providing 1000 W m−2 of power spectral density. The External and Internal Quantum efficiency of more than 95% is achieved by the designed solar cell.

Magnesium is one of the most common metals in the Earth’s crust, so Mg(OH)2 nanomaterials made directly from magnesium metal have a wide range of applications. Mg(OH)2 nanosheets can be synthesised directly from Mg powder and H2O2 solution below 200 °C. The thickness of these plates decreases as the sample processing temperature increases. The optical bandgap of the synthesised samples ranges from 5.0 eV to 5.7 eV. At 25 °C, the synthesised Mg(OH)2 nanosheets could detect NH3 gas. The gas sensing mechanism was proposed and discussed, where the Mg(OH)2/H2O structure was considered a p-type semiconductor with the carrier of H3O+. The effects of parameters, such as working temperature and ambient humidity, on the electrical resistance and gas sensing properties of the Mg(OH)2 nanosheets were investigated. The NH3 sensing properties of these materials at room temperature were also compared with those of other nanomaterials.

We design silica from rice husk as a precursor for mesoporous silica nanoparticles (MSN), which is eco-friendly, low-cost, and abundant in availability, replacing tetraethyl orthosilicate, which is expensive and its vapours cause blindness, by the facile method, i.e., sol-gel. The different pore sizes of MSN have been successfully reached by tuning the synthesis conditions of surfactant concentrations and hydrothermal treatment temperatures. The smallest pore size of MSN is 2.62 nm, with the most significant surface area of 19.169 m2/g. The higher surfactant concentrations affect the decrease of particle size of MSN, but the higher hydrothermal treatment temperatures affect the opposite. In addition, these factors affect the morphology, the graph of isotherm, and the atomic elements of MSN. Thus, the resulting MSN will be applied to nanocontainers of corrosion inhibitor because of getting the small pore size.

The dextran-coated superparamagnetic iron oxide nanoparticles (SPIONs) grafted with foliate (FA) were prepared and used as a nanocarrier for ellipticine (ET) delivery in cervical cancer. In this work we prepared superparamagnetic iron oxide nanoparticles by pulsed laser ablation in liquid method. The formation of the SPION@DEX-ET-FA nanosystem was performed by a reverse microemulsion process. Dynamic light scattering (DLS), atomic force microscopy (AFM), and field emission scanning electron microscope (FESEM) were used to characteristic the morphological properties of the NPs. The appropriate impact of a therapeutic dose of SPION@DEX-ET-FA on both cancer and healthy cell lines was estimated using a 3- (4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazolium bromide (MTT) assay. The flow cytometry assays was used to evaluate the induction of apoptosis in Hela cervical cancer cells. The findings of the SPION@DEX-ET-FA formulated were spherical particles with an average size, polydispersity and a zeta potential of 101 ± 15.02 nm, 0.075 and −33.8 mV, respectively. The nanosystem displayed dose-dependent cytotoxic effects on Hela cells. The results showed that SPION@DEX-ET-FA retained antitumor activity and no adverse effects on healthy cells were found.

Inertial migration of micro- and nanoparticles flowing through microchannels is commonly used for particle separation, sorting, and focusing on many lab-on-a-chip devices. Computer simulations of inertial migration of nanoparticles by mesoscale simulation methods, such as Dissipative Particle Dynamics (DPD) would be helpful to future experimental development of these lab-on-a-chip devices. However, the conventional DPD approach has a low Schmidt number and its ability to model inertial migration is questioned. In this work, we examine the ability of DPD simulations to investigate the inertial migration of rigid nanoparticles flowing through a slit channel. By varying the exponent and cutoff distance in the weight function of the random and dissipative forces, DPD models with Schmidt number varying between 1 and 370 were examined. We show that solvent penetration into nanoparticles and solvent-induced attraction between nanoparticles can be controlled by choosing appropriate interaction coefficients of the DPD conservative force and that these properties are not influenced by the Schmidt number of the DPD model. On the other hand, hydrodynamic properties and transport behaviour of rigid nanoparticles are influenced by the Schmidt number. With the conventional DPD model, nanoparticles tend to be evenly distributed across the channel and do not remain in steady-state positions during flow. At high Schmidt numbers, the particles migrate to long-lasting steady-state positions located between the channel center and walls, in agreement with known experimental observations. We conclude that to properly simulate inertial migration, modifications to the conventional DPD model that yield a high Schmidt number are required.

Selective, sensitive and accurate gas monitoring system can help to control the air pollution, prevent an explosion and injury to industrial workers. Due to very high surface to volume ratio and unique properties, graphene is a highly suitable carbon material to detect toxic gases. As single layer, few layer or multi-layer, graphene either in pure form or after modifications has been studied for the application in gas sensors. Present paper serves as a compendium of research work carried out on graphene and its derivatives in gas sensing applications. Review is mainly concentrated on the sensing of three toxic gases namely nitrogen dioxide (NO2), carbon monoxide (CO) and ammonia (NH3). Special emphasis is done on describing the mechanisms for gas sensing by pristine graphene and after modifications.

The dry reforming of methane is a potential solution to mitigate the global warming effect. In this study, the effects of various preparation methods including the impregnation, coprecipitation, and combined coprecipitation-impregnation on physical characteristics and DRM catalytic performance of Ni-CeO2-Al2O3 were investigated. The synthetic procedure was discovered to have a crucial role in the basicity and reducibility, as well as nickel dispersion of catalyst. With affordable basicity and high reducibility, the combination of coprecipitation-impregnation exhibited the best performance with CH4 and CO2 steady-state conversions of 72% and 82%, respectively. Moreover, the deactivation of catalysts was also studied. The formation of low graphitic type showed less harmful to catalyst.

Co-doping is an effective strategy to optimise the photovoltaic performance of GQDs. However, due to the heterogeneity of GQDs, it is difficult to achieve controllable photovoltaic performance without determining the structure-property relationship. In this work, we perform first-principles calculations to investigate the optoelectronic properties of GQDs doped with S, B, and P atoms. Our results show that S doping is crucial for tuning the photoelectric performance of S,B and S,P co-doped GQDs. Increasing the polarity of the solvent improves the charge transfer performance of single P-doped GQDs. Moreover, single P-doped GQDs show better photovoltaic performance than other doping configurations. Furthermore, the addition of B co-dopants to GQDs with Sh doping configuration improves the energy conversion of GQDs compared to B doping alone. Our study provides guidance for the rational design of GQDs for various photovoltaic applications.

As-prepared samples of La1.5Sr0.5NiO4 (LSNO) and BaTiO3 (BTO) were prepared by ball milling method combined with heat treatment. X-ray diffraction analysis showed the pure phases of LSNO with a tetragonal structure and BTO with a cubic structure. Average crystalline sizes were 15 and 35 nm for the LSNO and BTO samples, respectively. Lattice parameters ​​of LSNO and BTO were almost unchanged after compositing, indicating no diffusion or chemical reaction between them during the compositing process. Adding LSNO to the BTO-based material significantly improved the ferroelectric and ferromagnetic properties, contributing to the enhancement of the electrical polarisation of the composites. These enhancements also boosted the microwave absorption performance of the composites. In detail, 20LSNO/80BTO nanocomposite embedded in acrylic paint could achieve the reflection loss up to −27 dB, meaning 99.8% of the incident microwave being absorbed. This absorber could also reach absorptivity over 60% for almost the whole range of the K u band frequency, which proved that 20LSNO/80BTO nanocomposite could be used as a good microwave absorber for practical applications.

The recent technological revolution in nanoscience has created a huge potential to build highly sensitive, low-cost and power efficient portable sensors. Here, we have investigated the novel nano-porous penta-graphene nanotube (PGNT) device for detection and separation of halogen gases like fluorine (F2), chlorine (Cl2), bromine (Br2) and iodine (I2). The host carbon atoms are selectively removed to create the nanopores on the tube surface. 1, 2, 3 and 4 host carbon atoms are removed from the surface to create vacancies which were then investigated for detection and separation of halogen gases using functionalisation of pore edges. The I-V measurements were performed to establish the gas detection application of these novel porous structures. Furthermore, interaction energy graphs were obtained which show efficient separation of various halogen molecules by functionalising the pores with F2, Cl2 and H atoms.

Because of its distinctive optical and electrical characteristics, titanium dioxide (TiO2) thin films are one of the significant and promising semiconductor materials for environmental and energy applications. The effect of the laser pulse energy of Nd:YAG on the properties of TiO2 thin film grown on silicon and quartz substrates using the laser pulse deposition technique by the crystal structure, surface area, crystalline structure, average particle size, and porosity were summarised. The nano-thin film with the optimum condition has been prepared with a pulse laser energy of 900 mJ. The optical properties have been investigated using UV–vis spectrophotometer, morphological properties have been studied using atomic force microscopy and field emission scanning electron microscopy, and structural properties have been examined using x-ray diffractometer and Raman spectrometer. The tests and measurements have shown a crystalline structure, and the distribution of the grains was regular in the film. Raman spectroscopy showed two diffraction peaks corresponding to anatase Eg and rutile Eg. This observation is typically used in dye-sensitised solar cells, separation sensor devices, and more.

In this study, the feasibility of the production of electrospun nanofibre composite mainly for biomedical applications is reported. Biocompatible polyether-based polyurethane, natural proteinaceous polymer silk sericin (SS) and natural inorganic nanoclay halloysite as a drug carrier with a model drug chlorhexidine acetate were used to produce nanofibres by electrospinning technique. Sericin was extracted from Bombyx mori silk cocoons by high pressure high temperature (HT-HP) degumming. Chlorhexidine acetate (CA), an antimicrobial agent, was loaded into halloysite nanotubes (HNTs) at different weight ratios, and 1:1 weight ratio showed the maximum loading which was confirmed by TGA and XRD analysis. Electrospinning of polymer solution with different compositions of polyurethane, sericin, CA and CA-HNTs was conducted at 10% w/v concentration, 20 kV voltage, 15 μl min−1 flow rate and 10 cm distance which resulted in the formation of bead-free uniform fibres. Antimicrobial activity of nanofibrous webs was evaluated by the disc diffusion method (AATCC 90) and it was found that CA and CA-HNT loaded nanofibres show sustained antibacterial action against both the Gram-positive (S. aureus) and Gram-negative (E. coli) bacteria. The CA-HNT and sericin/CA-HNT loaded nanofibres showed controlled release of CA. In addition, the cytocompatibility assessment of developed nanofibrous composites showed good biocompatibility. Hence the produced composite nanofibre can serve as an excellent material for sustained drug release for various biomedical applications.

This work presents a successful and novel method for the preparation of Nb2O5 nanoparticles via pulsed laser ablation in liquid (PLAL) by employing a pure Nb plate and deionised water. The effect of various laser fluences on the chemical, structural, morphological and optical characteristics was studied. Chemical characteristics confirmed the formation of the orthorhombic T-Nb2O5 structure. While the morphology characteristics showed spherical particles and its density dependency on the laser fluence. The Nb2O5 stoichiometry ranged between 42.20% and 88.86%. Additionally, the structural analysis showed peaks related to the orthorhombic T-Nb2O5 structure with grain size between 58.2 and 244.6 nm. Lastly, topographical images showed that the average particle size was in the range 6.8 and 32 nm, and sample roughness was between 17.39 and 1.377 nm.