Nanotechnology

Clean room facilities are becoming more popular in both academic and industry settings, including low-and middle-income countries. This has led to an increased demand for cost-effective gas sensors to monitor air quality. Here we have developed a gas sensor using CoNiO2 nanoparticles through a cost-effective combustion method. The sensitivity and selectivity of the sensor towards CO2 were influenced by the structure of the nanoparticles, which were affected by the reducing agent (biofuels) used during synthesis...

In the current investigation, Zinc oxide (ZnO) nanoparticles and Fe-doped ZnO nanoparticles were sustainably synthesized utilizing an extract derived from the Rumex dentatus plant through a green synthesis approach. The Scanning electron microscope (SEM), X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDX), Ultra-violet visible spectroscopy (UV-vis) spectroscopy, Fourier-transform infrared spectroscopy (FTIR), and Thermogravimetric analysis( TGA) techniques were used to examine the compositional, morphological, optical, and thermal properties of both samples...

We report on the fabrication of a novel design of GaAs/(In,Ga)As/GaAs radial nanowire heterostructures on a Si 111 substrate, where, for the first time, the growth of inhomogeneous shells on a lattice mismatched core results in straight nanowires instead of bent. Nanowire bending caused by axial tensile strain induced by the (In,Ga)As shell on the GaAs core is reversed by axial compressive strain caused by the GaAs outer shell on the (In,Ga)As shell. Progressive nanowire bending and reverse bending in addition to the axial strain evolution during the two processes are accessed by in situ by X-ray diffraction...

The growth kinetics of colloidal lead halide perovskite (LHP) nanomaterials are an integral part of their applications, remains poorly understood due to complex nucleation processes and lack of in-situ size monitoring method. Here we demonstrated that absorption spectra can be used to observe in-situ growth processes of ultrathin CsPbBr3 nanowires in solution with reference to the effective mass infinite deep square potential well model. By means of this method, we have found that the ultrathin nanowires, fabricated by hot injection method, were firstly formed within one minute...

We have experimentally demonstrated spatially selective absorption in Ag-SiO2 -Ag based trilayer thin films by tuning the deposition angle of SiO2 layer. These structures generate cavity resonance which can be tuned across the substrate locations due to spatially selective thickness and refractive index of silicon oxide (SiO2 ) film sandwiched between metallic silver (Ag) mirrors. Spatially selective property of SiO2 film is obtained by oblique angle deposition (OAD) technique using an electron beam evaporation system...

Electronic transport in monolayer MoS2 is significantly constrained by several extrinsic factors despite showing good prospects as a transistor channel material. Our paper aims to unveil the underlying mechanisms of the electrical and magneto-transport in monolayer MoS2 . In order to quantitatively interpret the magneto-transport behavior of monolayer MoS2 on different substrate materials, identify the underlying bottlenecks, and provide guidelines for subsequent improvements, we present a deep analysis of the magneto-transport properties in the diffusive limit...

A hierarchical sea urchin-like hybrid metal oxide nanostructure of ZnO nanorods deposited on TiO2 porous hollow hemisphere with a thin zinc titanate interface layer is specifically designed and synthesized forming a combined type I straddling and type II staggered junctions. The HHSs, synthesized by electrospinning, facilitate light trapping and scattering. The ZnO nanorods offer a large surface area for improved surface oxidation kinetics The interface layer of zinc titanate (ZnTiO3) between the TiO2 HHSs and ZnO nanorods regulates the charge separation in a closely coupled hierarchy structure of ZnO/ZnTiO3/TiO2...

The fundamentals, performance, and applications of piezoresistive strain sensors based on polymer nanocomposites are summarized herein. The addition of conductive nanoparticles to a flexible polymer matrix has emerged as a possible alternative to conventional strain gauges, which have limitations in detecting small strain levels and adapting to different surfaces. The evaluation of the properties or performance parameters of strain sensors such as the elongation at break, sensitivity, linearity, hysteresis, transient response, stability, and durability are explained in this review...

In this work, the plasmonic effect of Au and Ag nanoparticles in the heterostructure photocatalyst system (TiO2/rGO) was studied. The laser ablation approach was applied to synthesize Au and Ag nanoparticles to eliminate impurity influence in this plasmonic study. Characterizing tools such as SEM, TEM, XRD, Raman, UV-vis spectral techniques were applied to obtain morphological information and optical properties of the nanocomposites. Photocatalytic properties of ternary nanocomposities such as, TiO2/rGO/Ag and TiO2/rGO/Au, were evaluated against Methylene blue and Congo red dyes with changing concentration of plasmonic nanoparticles (Au and Ag) and it was founded that the nanocomposite with the concentration of 10-11 mol/L Au NPs in TiO2/rGO has the best photocatalytic activity...

Achieving energy-efficient and high-performance field-effect transistors (FETs) is one of the most important goals for future electronic devices. This paper reports semiconducting single-walled carbon nanotube FETs (s-SWNT-FETs) with an optimized high-k relaxor ferroelectric insulator P(VDF-TrFE-CFE) thickness for low-voltage operation. The s-SWNT-FETs with an optimized thickness (~ 800 nm) of the high-k insulator exhibited the highest average mobility of 14.4 cm2 V-1 s-1 at the drain voltage (ID ) of 1 V, with a high current on/off ratio (Ion/off >105 )...

Nanoscale variations of optical properties in transition metal dichalcogenide (TMD) monolayers can be explored with cathodoluminescence (CL) and electron energy loss spectroscopy (EELS) using electron microscopes. To increase the CL emission intensity from TMD monolayers, the MoSe2 flakes are encapsulated in hexagonal boron nitride (hBN), creating van der Waals (VdW) heterostructures. Until now, the studies have been exclusively focused on scanning transmission electron microscopy (STEM-CL) or scanning electron microscopy (SEM-CL), separately...

The pursuit of van der Waals (vdW) heterostructures with high Curie temperature and strong perpendicular magnetic anisotropy is vital to the advancement of next generation spintronic devices. First-principles calculations are used to study the electronic structures and magnetic characteristics of GaN/VS2 vdW heterostructure under biaxial strain and electrostatic doping. Our findings show that a ferromagnetic ground state with a remarkable Curie temperature (477 K), much above room temperature, exists in GaN/VS2 vdW heterostructure and 100% spin polarization efficiency...

Highly-crystallized carbon nitride (HCCN) nanosheets exhibit significant potential for advancements in the field of photoelectric conversion. However, to fully exploit their potential, a thorough understanding of fundamental excitonic photophysical processes is crucial. Here, the temperature-dependent excitonic photoluminescence (PL) of HCCN nanosheets and amorphous polymeric carbon nitride (PCN) is investigated using steady-state and time-resolved PL spectroscopy. The exciton binding energy of HCCN is determined to be 109...

Remote thermal sensing has emerged as a temperature detection technique for tasks in which standard contact thermometers cannot be used due to environment or dimension limitations. One of such challenging tasks is the measurement of temperature in microelectronics. Here, optical thermometry using co-doped and mixed dual-center Gd2O3:Tb3+/Eu3+ samples were realized. Ratiometric approach based on monitoring emission intensities of Tb3+ (5D4-7F5) and Eu3+ (5D0-7F2) transition provided sensing in the range of 30-80 oC...

The fluorescence quenching of carboxyl-rich g-C3N4 nanoparticles was found to be selective to Ag+ and Ce3+ with a limit of detection as low as 30 pM for Ag+ ions. A solid-state thermal polycondensation reaction was used to produce g-C3N4 nanoparticles with distinct green fluorescence and high water solubility. Dynamic light scattering indicated an average nanoparticle size of 95 nm. The photoluminescence absorption and emission maxima were centered at 405 nm and 540 nm respectively which resulted in a large Stokes shift...

Numerous efforts have been undertaken to mitigate the Debye screening effect of FET biosensors for achieving higher sensitivity. There are few reports that show sub-femtomolar detection of biomolecules by FET mechanisms but they either suffer from significant background noise or lack robust control. In this aspect, deformed/crumpled graphene has been recently deployed by other researchers for various biomolecule detection like DNA, COVID-19 spike proteins and immunity markers like IL-6 at sub-femtomolar levels...

Recent advances in materials science, device designs and advanced fabrication technologies have enabled the rapid development of transient electronics, which represents a class of devices or systems that their functionalities and constitutions can be partially/completely degraded via chemical reaction or physical disintegration over a stable operation. Therefore, numerous potentials, including zero/reduced waste electronics, bioresorbable electronic implants, hardware security, and others, are expected. In particular, transient electronics with biocompatible and bioresorbable properties could completely eliminate the secondary retrieval surgical procedure after their in-body operation, thus offering significant potentials for biomedical applications...

Membrane distillation technology could utilize low-grade heat to desalinate brine, but the membrane material often suffers from disadvantages of low permeation flux and weak robustness to contaminants. To address these issues, the commercial polytetrafluoroethylene (PTFE) membrane was modified by cost-effective chemicals of tannic acid and (3-Aminopropyl)-triethoxysilane (APTES) to construct hydrophilic/underwater superoleophobic nano-rough structures on the surface to enhance its flux and oil-fouling resistance in direct contact membrane distillation (DCMD)...

In this work, an advanced hybrid material construction by cooperating niobium pentoxide (Nb2O5) nanoparticles with nitrogen-doped carbon (NC) derived from ZIF-8 dodecahedrons was prepared and used as a support, referred to as Nb2O5/NC. Pt nanoparticles (NPs) was dispersed onto Nb2O5/NC by a simple impregnation reduction method. The obtained Pt/Nb2O5/NC electrocatalyst showed high ORR activity due to three-phase mutual contacting structure with well-dispersed Pt and Nb2O5 NPs. In addition, the conductive NC is benefit to electron transfer while the induced Nb2O5 can regulate electronic structure of Pt element and anchor Pt NPs, thereby enhancing the ORR activity and stability...

Evolving technology advancements has accelerated the pursuit of transparent conducting thin films (TCF) with superior mechanical properties, durability, efficient opto-electrical performance and substrate compatibility as a pivotal focus in the realm of flexible transparent electronics. With this concern, this work delves the fabrication of multilayer silver nanowire (AgNW) thin films reinforced by zinc tin oxide (ZTO) thin film encapsulation on polycarbonate substrates by the combination of sputtering and spin-coating techniques...