Facile Microemulsion Synthesis of Vanadium-Doped ZnO Nanoparticles to Analyze the Compositional, Optical, and Electronic Properties

Functionalized ZnO-Based Nanocomposites for Diverse Biological Applications: Current Trends and Future Perspectives

The wide array of structures and characteristics found in ZnO-based nanostructures offers them a versatile range of uses. Over the past decade, significant attention has been drawn to the possible applications of these materials in the biomedical field, owing to their distinctive electronic, optical, catalytic, and antimicrobial attributes, alongside their exceptional biocompatibility and surface chemistry. With environmental degradation and an aging population contributing to escalating healthcare needs and costs, particularly in developing nations, there's a growing demand for more effective and affordable biomedical devices with innovative functionalities. This review delves into particular essential facets of different synthetic approaches (chemical and green) that contribute to the production of effective multifunctional nano-ZnO particles for biomedical applications. Outlining the conjugation of ZnO nanoparticles highlights the enhancement of biomedical capacity while lowering toxicity. Additionally, recent progress in the study of ZnO-based nano-biomaterials tailored for biomedical purposes is explored, including biosensing, bioimaging, tissue regeneration, drug delivery, as well as vaccines and immunotherapy. The final section focuses on nano-ZnO particles' toxicity mechanism with special emphasis to their neurotoxic potential, as well as the primary toxicity pathways, providing an overall review of the up-to-date development and future perspectives of nano-ZnO particles in the biomedicine field.

Recent Advances in Synthesis and Application of Metal Oxide Nanostructures in Chemical Sensors and Biosensors

Nanostructured materials formed from metal oxides offer a number of advantages, such as large surface area, improved mechanical and other physical properties, as well as adjustable electronic properties that are important in the development and application of chemical sensors and biosensor design. Nanostructures are classified using the dimensions of the nanostructure itself and their components. In this review, various types of nanostructures classified as 0D, 1D, 2D, and 3D that were successfully applied in chemical sensors and biosensors, and formed from metal oxides using different synthesis methods, are discussed. In particular, significant attention is paid to detailed analysis and future prospects of the synthesis methods of metal oxide nanostructures and their integration in chemical sensors and biosensor design.

Effect of Thermal Treatment on the Structure and Morphology of Vanadium Doped ZnO Nanostructures Obtained by Microwave Assisted Sol-Gel Method

In this paper, we conducted a fundamental study concerning the effect of thermal treatment on the structure and morphology of 2 mol% vanadium doped ZnO nanopowders obtained by microwave assisted sol-gel method (MW). The samples were analyzed by DTA, FTIR, XRD, SEM, and UV-Vis spectroscopy. The DTA results showed that above 500 °C, there was no mass loss in the TG curves, and ZnO crystallization occurred. The XRD patterns of the thermally treated powders at 500 °C and 650 °C showed the crystallization of ZnO (zincite) belonging to the wurtzite-type structure. It was found that in the 650 °C thermally treated powder, aside from ZnO, traces of Zn₃(VO₄)₂ existed. FTIR spectra of the annealed samples confirmed the formation of the ZnO crystalline phase and V-O bands. The micrographs revealed that the temperature influenced the morphology. The increase in the annealing temperature led to the grain growth. The SEM images of the MW powder thermally treated at 650 °C showed two types of grains: hexagonal grains and cylindrical nanorods. UV-Vis spectra showed that the absorption band also increased with the increasing temperature of thermal treatment. The MW sample annealed at 650 °C had the highest absorption in ultraviolet domain.

A Survey on Analytical Methods for the Characterization of Green Synthesized Nanomaterials

Nowadays, nanotechnologies are well established and the uses of a great variety of nanomaterials show exponential growth. The development of green synthesis procedures experienced a great development thanks to the contribution of researchers of diverse origins. The versatility of green chemistry allows producing a wide range of organic and inorganic nanomaterials with numerous promising applications. In all cases, it is of paramount importance to carefully characterize the resulting nanomaterials because their properties will determine their correct performance to accomplish the function to which they were synthesized or even their detrimental effects like nanotoxicological behavior. This review provides an overview of frequently employed characterization methods and their applications for green synthesized nanomaterials. However, while several different nanoscale materials and their associated green construction methodology are being developed, other important techniques would be extensively incorporated into this field soon. The aim is to encourage researchers in the field to employ a variety of these techniques for achieving an exhaustive characterization of new nanomaterials and for contributing to the development of validated green synthesis procedures.

High-Performance Flexible Ultraviolet Photodetectors with Ni/Cu-Codoped ZnO Nanorods Grown on PET Substrates

As a developing technology for flexible electronic device fabrication, ultra-violet (UV) photodetectors (PDs) based on a ZnO nanostructure are an effective approach for large-area integration of sensors on nonconventional substrates, such as plastic or paper. However, photoconductive ZnO nanorods grown on flexible substrates have slow responses or recovery as well as low spectral responsivity R because of the native defects and inferior crystallinity of hydrothermally grown ZnO nanorods at low temperatures. In this study, ZnO nanorod crystallites are doped with Cu or Ni/Cu when grown on polyethylene terephthalate (PET) substrates in an attempt to improve the performance of flexible PDs. The doping with Ni/Cu or Cu not only improves the crystalline quality but also significantly suppresses the density of deep-level emission defects in as-grown ZnO nanorods, as demonstrated by X-ray diffraction and photoluminescence. Furthermore, the X-ray photoelectron spectroscopy analysis shows that doping with the transition metals significantly increases the oxygen bonding with metal ions with enhanced O/Zn stoichiometry in as-grown nanorods. The fabricated flexible PD devices based on an interdigitated electrode structure demonstrates a very high R of ~123 A/W, a high on-off current ratio of ~130, and a significant improvement in transient response speed exhibiting rise and fall time of ~8 and ~3 s, respectively, by using the ZnO nanorods codoped by Ni/Cu.

Synthesis and Diagnostics of Nanostructured Micaless Microcomposite as a Prospective Insulation Material for Rotating Machines

This paper deals with the topic of composite insulation materials for rotating machines and it is primarily pointed to the synthesis of new three-component insulation system. In connection with this research, the basic components of the insulation system are selected and described by different diagnostic methods. The proposed insulation material is composed of epoxy resin based on bisphenol-A diglycidyl ether, magnesium oxide nanofiller (1 wt %) with its own surface treatment technology using epoxysilane coupling agent ( γ -glycidoxypropyltrimethoxysilane) and polyethylene naphthalate as a reinforcing component. Following the defined topic of the paper, the proposed three-component insulation system is confronted with commonly used insulating systems (PET reinforced and Glass reinforced mica composites) in order to verify the basic dielectric properties (dielectric strength, volume resistivity, dissipation factor) and other parameters determined from phenomenological voltage and current signals, respectively.