Solid State Phenomena Vol. 222

Abstract: Nanoparticle or an ultrafine particle is a small solid whose physical dimension lies between 1 to 100 nanometers. Nanotechnology is the coming revolution in molecular engineering, and therefore, it is curiosity-driven and promising area of technology. The field of nanoscience and nanotechnology is interdisciplinary in nature and being studied by physicists, chemists, material scientists, biologists, engineers, computer scientists, etc. Research in the field of nanoparticles has been triggered by the recent availability of revolutionary instruments and approaches that allow the investigation of material properties with a resolution close to the atomic level. Strongly connected to such technological advances are the pioneering studies that have revealed new physical properties of matter at a level intermediate between atomic/molecular and bulk. Quantum confinement effect modifies the electronic structure of nanoparticles when their sizes become comparable to that of their Bohr excitonic radius. When the particle radius falls below the excitonic Bohr radius, the band gap energy is widened, leading to a blue shift in the band gap emission spectra, etc. On the other hand, the surface states play a more important role in the nanoparticles, due to their large surface-to-volume ratio with a decrease in particle size (surface effects). From the last few years, nanoparticles have been a common material for the development of new cutting-edge applications in communications, energy storage, sensing, data storage, optics, transmission, environmental protection, cosmetics, biology, and medicine due to their important optical, electrical, and magnetic properties.

Abstract: Nowadays, oxide nanomaterials have received great attention due to their unique semiconducting, optical and electrical properties. Oxide nanomaterials exhibit these properties due to their small size, high surface area to volume ratio and great biocompatibility. The chemical activity of the oxide nanomaterials is highly enhanced by the presence of oxygen vacancies in these materials. This review article outlined the unique properties, synthesis techniques and applications of oxide nanomaterials.The important and unique properties of TiO₂ and ZnO nanomaterials with their possible crystal structures have been discussed. In application part, the oxide nanomaterials especially ZnO has been discussed for memory device applications. To control the performance of oxide nanomaterials for memristor device application, a better understanding of their properties is required.Table of Contents

Abstract: The technical and economic growth of the twentieth century was marked by evolution of electronic devices and gadgets. The day-to-day lifestyle has been significantly affected by the advancement in communication systems, information systems and consumer electronics. The lifeline of progress has been the invention of the transistor and its dynamic up-gradation. Discovery of fabricating Integrated Circuits (IC’s) revolutionized the concept of electronic circuits. With advent of time the size of components decreased, which led to increase in component density. This trend of decreasing device size and denser integrated circuits is being limited by the current lithography techniques. Non-uniformity of doping, quantum mechanical tunneling of electrons from source to drain and leakage of electrons through gate oxide limit scaling down of devices. Heat dissipation and capacitive coupling between circuit components becomes significant with decreasing size of the components. Along with the intrinsic technical limitations, downscaling of devices to nanometer sizes leads to a change in the physical mechanisms controlling the charge propagation. To deal with this constraint, the search is on to look around for alternative materials for electronic device application and new methods for electronic device fabrication. Such material is comprised of organic molecules, proteins, carbon materials, DNA and the list is endless which can be grown in the laboratory. Many molecules show interesting electronic properties, which make them probable candidates for electronic device applications. The challenge is to interpret their electronic properties at nanoscale so as to exploit them for use in new generation electronic devices. Need to trim downsize and have a higher component density have ushered us into an era of nanoelectronics.

Abstract: To reduce the cost of solar electricity, there is an enormous potential of thin-film photovoltaic technologies. An approach for lowering the manufacturing costs of solar cells is to use organic (polymer) materials that can be processed under less demanding conditions. Organic/polymer solar cells have many intrinsic advantages, such as their light weight, flexibility, and low material and manufacturing costs. But reduced thickness comes at the expense of performance. However, thin photoactive layers are widely used, but light-trapping strategies, due to the embedding of plasmonic metallic nanoparticles have been shown to be beneficial for a better optical absorption in polymer solar cells. This article reviews the different plasmonic effects occurring due to the incorporation of metallic nanoparticles in the polymer solar cell. It is shown that a careful choice of size, concentration and location of plasmonic metallic nanoparticles in the device result in an enhancement of the power conversion efficiencies, when compared to standard organic solar cell devices.Contents of Paper

Abstract: Various biomedical applications of nanomaterials have been proposed in the last few years leading to the emergence of a new field in diagnostics and therapeutics. Most of these applications involve the administration of nanoparticles into patients. Carbon Nanotubes are enjoying increasing popularity as building blocks for novel drug delivery systems as well as for bioimaging and biosensing. The recent strategies to functionalize carbon nanotubes have resulted in the generation of biocompatible and water-soluble carbon nanotubes that are well suited for high treatment efficacy and minimum side effects for future cancer therapies with low drug doses. The toxicological profile of such carbon nanotube systems developed as nanomedicines will have to be determined prior to any clinical studies undertaken.

Abstract: As the development of nanotechnology has extended to the world of biomolecules, a revolution has occurred in the design and assembly of nanomaterials for drug delivery with a significant potential to impact drug efficacy and patient outcomes. Currently a number of nanomaterials are under investigation for their suitability as sustained, controlled and targeted drug carriers. Leading edge of the rapidly developing nanosciences is the development and assessment of these nanomaterials, with specific physicochemical properties different from their larger/ bulk counterparts, as vehicles for transport of small and large drug molecules. The characteristics such as size, shape, chemical composition, surface structure and charge, aggregation and agglomeration, and solubility, can greatly influence interactions of these nanostructured systems or carriers with biomembranes and cells. The selectivity and reactivity achieved due to the very small size assigns these systems with a wide spectrum of applications. In this review, nanomaterials are considered in terms of the physical attributes or pharmaceutical effects allocated by them to the all-inclusive carrier or vehicle system (s). However we will limit our discussion to lipidic and polymeric nanomaterials, the two most commonly promoted, and safe nanosystems for delivery of both, the chemical or small molecular entities (SME) and the macromolecules including genes and siRNA.Contents of Paper

Abstract: In this report, Aldo-keto (Aldehydes and Ketones) method, a soft root of synthesis of inorganic materials was employed to prepare YPO4:Eu³⁺ nanophosphors. The as-prepared samples were characterized by X-ray diffraction (XRD), and scanning electron microscope (SEM) for structural and morphological studies. The complete agreement of XRD with standard ICDD data confirms the formation of required phase. The particle size conformation was done through Debye Scherrer formula. The luminescence studies were carried out by photoluminescence (PL) spectroscopy. The PL spectra reveal that the orange emission (⁵D₀→⁷F₁) was more intense than a normal red emission (⁵D₀→⁷F₂). Also the tuning of color purity was done through concentration variation.

Abstract: Chalcogenide semiconductor nanoparticles and their self-assembly structures have become the most explored group of semiconductor nanomaterials due to the interesting physics involved in quantum confinement, surface chemistry and variety of applications. In the last couple of decades, facile routes for their synthesis and strategies for controlling the size, shape and morphology have been reported. In the present review, synthesis strategies of size and shape controlled nanoparticles belonging to II-VI group of semiconductor chalcogenides are presented and each method for preparation of nanoparticles is critically analysed. Role of various factors that affect the nucleation and growth of nanoparticles is discussed at length. Nanoparticles and self-assemblies of CdSe, CdTe, HgTe and ZnSe are synthesized using new and facile single molecular precursor based noble route by our group that uses non-pyrophoric, low temperature and non-toxic chemicals, their properties and synthesis scheme are discussed as future development in this field. Some recent applications of chalcogenides QDs in the fields of solar cell, optical fibre amplifiers, biosensing and bo-imaging are discussed and reviewed.