Nitrogen-vacancy (NV) colour centres in diamond have attracted extensive attention in quantum precision measurement, computation and communication. In these fields, microwave manipulation is a technology in which antenna is used to radiate special microwave to manipulate the quantum spin state of NV colour centres. In this work, high frequency structure simulator software is used to design a microstrip antenna with a resonance frequency of 2.8756 GHz. Based on simulation and experiments, near field radiation of antenna is optimised to improve its microwave manipulation quality. This antenna will be helpful in the development of hybrid quantum devices of NV centres.

In this work, TiO₂ nanotube arrays/mesoporous silica composite coated with tannic acid-Fe(III) complex was prepared with a simple drip coating method. The coating significantly inhibited the burst release in the early stage of drug release. The coordination conditions of the material were different under different pH values. This resulted in different stabilities of the coating, thus controlling the release of Loxoprofen Sodium (LS) at different pH values to construct a pH-responsive drug delivery system. To demonstrate this principle, the authors loaded LS into the samples and triggered pH-induced release. The excellent biological activity of the samples was confirmed in vitro by the significant growth and differentiation of MC3T3-E1 osteoblastic cells. The data has shown that the samples had achieved intelligent control of drug release and would have a wide range of applications.

The electrochemical method of synthesis of silver nanoparticles (AgNPs) using ‘sacrificial’ silver anode as a source of Ag⁺, microbial origin surfactant (rhamnolipid, RL) as a stabiliser of AgNPs and electric current as a reducer is presented. Using of cyclic voltammetry it was determined that RL concentration and temperature are the main factors influencing the rate of anodic dissolution of silver and cathodic reduction of the formed complex [AgRL]⁺. Increasing of RL concentration leads to increasing of the cathodic currents that indicate the increase of the rate of AgNPs formation. With increasing the temperature from 40 to 60°C the values of the anode and cathodic currents increase to 1.5 times, this indicates the predominant diffusion nature of the influence of the temperature on the synthesis of AgNPs. Obtained AgNPs were investigated using transmission electron microscopy and it was found that increasing of concentration of surfactant leads to decreasing of the size of AgNPs, whereas increasing of temperature, on the contrary, leads to increasing of mean size of AgNPs. Synthesised AgNPs showed significant antimicrobial activity against the bacterial phytopathogens Xanthomonas campestris and Agrobacterium tumefaciens. It has been shown that AgNPs stabilised by RL are characterised by low phytotoxicity.

MnSiO₃ nanoparticles (NPs) were prepared by precipitation method, their structure and composition were characterised by transmission electron microscopy, electron diffraction spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Due to the oxidase-like enzyme activity of MnSiO₃, it can catalyse the substrate 3,3′,5,5′-tetramethylbenzidine (TMB) in acidic environment to form an oxidised TMB which has an absorption peak at 652 nm in the absence of hydrogen peroxide. When Fe²⁺ was added to the assay, the oxidase-like activity of MnSiO₃ was inhibited, and the intensity of the absorption at 652 nm was reduced. Based on the high oxidase-like activity, a colorimetric method for Fe²⁺ detection was established, it showed high selectivity and sensitivity. In the optimised conditions, the limit of detection was 0.5 μM with a linear range from 3 to 63 μM. Moreover, the method was applied to determine Fe²⁺ in spiked water samples which gave satisfactory recoveries.

Root canal ecosystem is a complex environment due to its anatomy and persistence of microorganisms; those may reside within the canal after therapeutic efforts and cause subsequent complications and treatment failure. Nanomaterials with unique physicochemical properties have high accessibility to untouched areas of the intracanal ecosystem. Therefore, they have attracted the attention of researchers on the efficacy of nanodentistry in endodontics. This Letter reviews the recent advances in nanodentistry, especially in root canal treatment. In addition, it focuses on the application of nanoparticles in treatment and prevention of a variety of post-treatment infections in endodontics, treatment of antibiotic resistance and bacterial biofilm structures. In addition, it points out applications of nanoparticles in endodontic materials, restorative materials, dental adhesives, implants, prostheses and dentures. At last, the Letter elaborates on how nanoparticles used for targeted endodontic drug delivery and their efficiently controlled releases.

Introduction of ethylene diamine into the layers of graphene oxide was achieved through direct compounding method. Graphene oxide intercalated with ethylene diamine was characterised by Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermo gravimetric analysis (TGA) and scanning electron microscopy–energy dispersive X-ray spectroscopy (SEM-EDX) techniques. The efficiency of the material in adsorbing chromium was evaluated through batch scale studies by optimising parameters like pH, concentration and contact time. The material renders a monolayer adsorption capacity of 69.93 mg/g, at pH 1 within 60 min time period for a minimal dosage of 0.05 g. The ethylene diamine modified graphene oxide thus appeals to be a promising adsorbent for environmental applications.

The development of a benign, cost-effective and eco-friendly system for the removal of pollutants from water is an ongoing challenge. In this regard, the authors first time explored a clean and sustainable mean for the synthesis of Au/Ag core–shell nanoparticles (NPs) using Ananas comosus leaves extract as a reducing and stabilising agent. Spectroscopic and microscopic techniques confirmed the formation of Au/Ag core–shell NPs with an average size range between 5 and 10 nm. The synthesised Au/Ag core–shell NPs showed the excellent catalytic potential for the reduction of 4-nitrophenol into 4-aminophemol within 15 min. Kinetic study explicates that the catalytic reaction obeys the pseudo-first-order kinetic law with an apparent rate constant (k _app) of 0.03 min⁻¹. Moreover, Au–Ag core–shell NPs showed exceptional stability over a long period (three months). Thus, this study provides a positive step towards the development of novel green catalysts.

Using co-hydrolysis of graphite oxide and cellulose in sulphate solution, nanocellulose (NC)/graphene oxide (GO) nanocomposite aqueous solution was prepared. The results of product size distribution showed that NC was well combined with GO in the NC/GO composite and better than the sample prepared by blending NC and GO solutions. The results from infrared spectroscopy and Raman spectroscopy showed that intense hydrogen bonds between NC and GO presented in NC/GO composite, while none were found in the mixture solution. The zeta potential results showed that the sample of NC/GO composite solution possessed higher stability than the sample prepared by the mixing method. The aqueous solution containing nanocomposite can be used to prepare NC/GO composites with high dispersibility.

One challenge in the application of traditional metastable intermolecular composite (MIC) material is that MIC particles are not compatible with micro-electro-mechanical system. In the authors’ work, a solution casting method was employed to prepare aluminium/polyvinylidene fluoride (Al/PVDF) MIC films. The morphological, structural and compositional information of the samples were characterised by scanning electron microscopy, X-ray diffraction, energy dispersive spectroscopy and Fourier transform infrared spectroscopy. The energy-release characteristics of Al/PVDF films were studied by thermogravimetric analysis and differential scanning calorimetry. The results show that heat output and mass loss increased as the thickness of MIC films reduced. The maximum heat release of the main exothermic peak was 1032 J/g. The kinetics process could be divided into three stages with apparent activation energy calculated by Kissinger and Starink methods of 128.86, 164.69 and 153.16 kJ/mol, respectively.

Human beings have been bearing great medical, social, and economic losses due to the ever-increasing rate of microbial infections and the development of resistance; hence, there is a dire need to develop novel strategic alternate tools to circumvent these infections. In this regard, metallic nanomaterials (NMs) have been reported to exhibit promising bactericidal properties. In the present study, two different shaped silver NMs, i.e. silver nanoparticles (AgNPs) and silver nanoprisms (AgNPrs) and their conjugates with azithromycin were synthesised, characterised, and tested for their bactericidal activity. The average particle sizes analysed for spherical nanoparticles were 30–47.5 nm, and for prismatic-nanoparticles was 35–60 nm, respectively. The distinct ultraviolet–visible peaks were obtained for NMs and their nanoconjugates. The results of Fourier transform infrared spectroscopy indicated the interaction of various functional groups from Azy with metallic NMs. The nanoprisms and their conjugates showed enhanced bactericidal potential as compared to AgNPs and their corresponding control. The efficiency of Azy–AgNPrs was statistically higher (P <0.05) than AgNPs, Azy–AgNPs, and AgNPrs against the growth of Escherichia coli and Staphylococcus aureus. These results can be used as an innovative tool for further in-depth optimisation of shape-dependent nanoconjugates for their bactericidal activity.

This Letter presents the electrodeposition of zinc oxide (ZnO) nanostructures by varying the negative potential and investigation of structural, optical, and morphological characteristics. UV–vis spectroscopy investigation showed the redshift of the absorption peak with the increased negative potential. Using Tauc relation, the optical bandgap values estimated to be 3.09, 2.97, 2.93, 2.91, 2.90, and 2.84 eV corresponding to the samples prepared at potential −0.5, −0.7, −0.9, −1.1, −1.3 and −1.5 V. Fluorescence spectra exhibited the UV emission band at wavelength 392 nm along with a peak at 650 nm corresponds to the second-order nature of ZnO. Fourier-transform infrared spectroscopy analysis confirmed the various vibration modes at 403, 493, and 702 cm⁻¹ originated by the ZnO nanostructures. X-ray diffraction pattern revealed the hexagonal wurtzite phase of ZnO. Scanning electron microscopy investigation evidenced the distinct morphology of ZnO with the increased negative potential; however, the dense and perpendicularly oriented ZnO nanorods are prepared at highest negative potential as compared to rice grain-like ZnO structure prepared at least negative potential. Furthermore, the prepared nanostructures are used as dye-sensitised solar cells (DSSCs) photoanodes, while the DSSC-Z6 showed the increased cell efficiency up to 1.2%, due to the aligned growth of the ZnO nanorods.

Three-dimensional Bi₂S₃ with different morphology of flower-like, waxberry like and hydrangea like on the tin-doped indium oxide substrate has been produced from one-step aqueous solution at low temperature (40–70°C) and fixed pH of 0.81 for 24 h. The UV–vis measurement showed that the absorption spectrums of obtained Bi₂S₃ crystals were occurred blue shift compared to the bulk orthorhombic Bi₂S₃(1.3 eV). With the increase in temperature, the crystallinity of Bi₂S₃ films was gradually improved. When the temperature went to 55°C, the best conductivity was obtained.

Hierarchical porous zinc oxide (ZnO)/silver (Ag) microspheres were prepared by two-step method. The porous ZnO microspheres were prepared firstly, and then Ag nanoparticles were evenly anchored on the surface of ZnO microspheres by Sn²⁺ activation method. The results show that ZnO is wurtzite phase, and Ag particles are only coated on the surface of ZnO microspheres. Compared with pure ZnO, there are two obvious absorption peaks of Ag-doped ZnO, which corresponds to the ultraviolet absorption peak of ZnO and the plasma resonance absorption peak of Ag, respectively. The intensities of photoluminescence peak of ZnO/Ag microspheres are significantly lower than that of pure ZnO. Moreover, ZnO/Ag microspheres show higher photocatalytic activity than ZnO, which may be attributed to the existence of highly dispersed Ag.

Memristors are considered to be next-generation non-volatile memory devices owing to their fast switching and low power consumption. Metal oxide memristors have been extensively investigated and reported to be promising devices, although they still suffer from poor stability and laborious fabrication process. Herein, the authors report a stable and power-efficient memristor with novel heterogeneous electrodes structure and facile fabrication based on cupric oxide (CuO)–cuprous oxide (Cu₂O) complex thin films. The proposed structure of the memristor contains an active complex layer of CuO and Cu₂O sandwiched between fluorine-doped tin oxide (FTO) and gold (Au) electrodes. The fabricated memristors demonstrate bipolar resistive switching (RS) behaviour with a low working voltage (∼1 V), efficient power consumption, and high endurance over 100 switching cycles. The authors suggest the RS mechanism of the proposed device is related to the formation and rupture of conducting filaments inside the memristor. Moreover, they analyse the conduction mechanism and electron transport in the active layer of the device during the RS process. Such a facile fabricated device has a promising potential for future memristive applications.

In this work, size-dependent stability and self-instability of non-uniform nanobeams are studied with consideration of the surface elasticity theory. The nanobeams are modelled as step-wise beams and the governing equation of the nanobeam is solved for different boundary conditions. At first, a backward formulation is developed to calculate the effective Young's modulus to compare it with experimental results. Wide ranges of numerical results are presented for buckling load and self-instability of Al and Si nanobeams with positive and negative surface properties. The obtained results indicate that the selection of the number of steps in the presence of surface effects has a considerable impact on the mechanical behaviour of non-uniform nanobeams. In addition, the aspect ratio of one section of a step-wise nanobeam with negative surface residual stresses can make the whole structure self-instable. The results for effective Young's modulus are compared with previous experiments and satisfactory agreement is illustrated.

The acquisition of a high-quality imaging performance by an atomic force microscope is significantly influenced by the motion coupling effect of its key scanning unit, i.e. its piezoelectric tube scanner. In this Letter, to improve its performance, a MIMO model predictive control scheme for reducing this effect is proposed. The proposed controller achieves this by greatly overcoming the problem of tilted characters in the atomic force microscopy (AFM) scanned images. The experimental results are demonstrating the effectiveness of the proposed control technique.

Surface plasmon resonance (SPR) or so-called plamonics behaviour is well-known for its tunability along the light absorption spectrum. Additionally, there are number of parameters alteration could be tuned to tailor the materials’ characteristics towards any special needs of the application. In this work, the authors report a novel metallic structure of silver nano-dendrites (Ag NDs) fabricated using electrochemistry deposition technique. This Ag NDs was implemented in the active layer of an organic photovoltaic to increase the light absorption in the intrinsic layer. The optical properties’ behaviour of these structures depicts that smaller assemblies can provide prominent SPR properties which will enhance the light trapping mechanism in the active layer of organic solar cells. The incident light will be trapped more efficiently and scattered extensively within the cell layers with the presence of Ag NDs arrays. The ultraviolet–visible and photoluminescence spectra show that the presence of Ag NDs enhances the absorption of light inside the organic solar cells’ layer compared to the original solar cell. The amount of collective light absorption at the active layer of an organic photovoltaic is very important in improving the efficiency of the device.

The effects of sputtering pressure on the O/Si ratio, microstructure, surface morphology and optical properties within 300–1100 nm of SiO₂ film via radio frequency magnetron sputtering were investigated. The results showed that the molar ratio of O/Si in the film increased from 1.96 to 2.03, from silicon rich to oxygen rich, with the sputtering pressure increase from 0.3 to 1.3 Pa. The SiO₂ films deposited at different pressure were all amorphous. There were many ditches with a length of about 50 nm on the surface of the film deposited at lower pressure. The increase of sputtering pressure could reduce the number of ditches, and make the surface denser and more uniform. The refractive index increased first, then decreased and finally increased with the increase of sputtering pressure, and the maximum and minimum values were obtained at 0.7 and 1.1 Pa, respectively. The change of absorptivity was approximately the same as that of the refractive index, while the change of the average transmittance of coated quartz glass was exactly the opposite of refractive index. The minimum value of the average transmittance 92.6% and the maximum value 93.1% were obtained at 0.7 and 1.1 Pa, respectively.