Recent Patents on Nanotechnology - Volume 4, Issue 1, 2010

Carbon nanotubes are currently the focus of intense interest due to their extraordinary properties. However, asgrown nanotubes exist as bundles of metallic and semiconducting. This hinders their widespread applications. Much progress has been made to overcome this limitation. Many separation methods have been investigated, including combination of physical, chemical, or biochemical methods. These methods have demonstrated their own advantages and limitations. This paper reviews recent patents progress made for the separation of metallic and semiconducting nanotubes.

Silicon nanotubes, as a novel kind of silicon nanomaterials, exhibit good application prospect in lithium ion battery, field effect transistors, magnetic nanodevices, hydrogen storage, nanoscale electron and field emitting devices. This article reviews the recent progress and patents in silicon nanotubes. The progress and corresponding patents for the synthesis of silicon nanotubes using different templates, hydrothermal method, electrochemical deposition, plasma method and laser ablation method are demonstrated. The experimental application and patents of silicon nanotubes as field effect transistors and lithium ion battery are discussed. The application potential of silicon nanotubes in magnetic devices, hydrogen storage, nanoscale electron and field-emitting devices is demonstrated. Finally, the future development of silicon nanotubes for the synthesis and practice application is also discussed.

With large surface-to-volume ratios and Debye length comparable to their small size, one-dimensional nanostructures have been extensively studied and have been widely used to fabricate many high-performance and new type nanoscale electronic and optoelectronic devices. In this work, we provide a comprehensive review on the state-to-theart research activities on the photodetectors application of one-dimensional nanostructures. The review begins with a survey of the patents and reports on the synthesis of one-dimensional nanostructures, which can be used to fabricate photodetectors. Then the recent progress on this topic is discussed, focusing on 1-D metal oxide, III-V group semiconductors, and other nanomaterials. This review will then be finalized with some perspectives and outlook on the future developments of this research topic.

In this paper, we reviewed the current development and patents for the application of high-brightness and highefficiency white light-emitting diode (LED). The high-efficiency GaN nanostructures, such as disk, pyramid, and rod were grown on LiAlO2 substrate by plasma-assisted molecular-beam epitaxy, and a model was developed to demonstrate the growth of the GaN nanostructures. Based on the results, the GaN disk p-n junction was designed for the application of high brightness and high efficiency white LED.

Nanoscale Au particles are received with significant interest in the recent years owing to their unique properties, which originate from the quantum scale dimension. Although colloidal Au has been known since ancient times for the decoration of glasses and for its curative powers, the technological importance has been understood only in the last two decades. The fascinating optical and electronic properties of the Au nanoparticles made them an excellent candidate in the development of nanoscale devices. Significant amount of research has been devoted to explore the technological application of these tiny particles. Various biosensing devices, catalytic interfaces and bioanalytical methodologies based on Au nanoparticles have been developed in the last two decades for different applications. Au nanoparticles are considered to be the key building blocks in the emerging nanoscale energy and sensing devices of 21st century. In this review, we highlight some of the recent patents and related literature on the bioanalytical applications of Au nanoparticles. A brief outline on the synthesis of Au nanoparticles of various size and shape and a detailed account of their potential utilization in the development of optical and electrochemical sensors/biosensors and analytical methods for drug delivery are discussed.

In recent years, polymeric scaffolds have been used in several biomedical applications for the delivery of drugs or other biologically relevant molecules. Polymeric nanostructures possess different (and in some cases more powerful) properties respect to bulk materials. This, leaded academic researchers and industry to cooperate in developing pioneering nanostructured materials for industrial and biomedical applications. Moreover, the preparation and use of systems with multiple (multifunctional) properties (i.e., bioconjugation with superparamagnetic, fluorescent or targeting molecules) will represent in the future a viable and innovative tool for application in several clinical fields. This brief critical review collects and discusses some recent patents about the preparation and use of these multifunctional nanoparticles in biomedicine and in non-invasive bioimaging applications.

Al-substituted M-type hexaferrite is a high anisotropy material. In this paper, we report the coprecipitation synthesis of SrAl4Fe8O19 powder and the effects of preheating temperature and calcining time on the anisotropy and magnetic property of the powders. The XRD analysis indicated that the SrAl4Fe8O19 powder requests a calcining time of 3 h for formation of pure hexagonal platelike particle, and preheat treatment at 300 °C was favorable for the formation of single phase SrAl4Fe8O19. Calculation of c/a value with XRD data indicated that the Al-substitution and preheat treatment induced notable increase of the atomic lattice anisotropy. SEM analysis revealed that shape anisotropy of the samples decreases with the preheating. Magnetic measurement indicates that coercivity decrease and magnetization increase as decrease in shape anisotropy, but have no concern with the atomic lattice anisotropy. The no-preheated sample has a maximum coercivity up to 3.9947 kG and the sample preheated at 400 °C has a maximum magnetization up to 32.266 A·m2·kg-1. The present article discusses some important patents related to catalysis of Mg-containing spinel compounds.

The patents annotated in this section have been selected from various patent databases. These recent patents are relevant to the article published in this journal issue, categorized by different nanotechnology methods, process an techniques involved.