Nanostructured Materials and their Applications

The great challenge in front of the twenty-first century is steady and smooth green energy supply for automobiles, optoelectronics, and recently invented IoT devices. To overcome these challenges, different kinds of energy storage mechanisms were propounded. The fuel cells, electrochemical supercapacitors, and Li-ion batteries were investigated extensively for high energy and power density. Various nanostructures have been reported with several merits. But still, no metal oxide has attained the required characteristics. Among them, Tungsten trioxide (WO₃) has fascinated the research people due to its excellent novel properties such as tunable optical band gap and interesting structures and morphology. Indeed, the electrochemical performance of hybrid nanocomposites of WO₃ reveals the practical application of supercapacitor. In this chapter, we briefly introduced the general synthesizing methods and recent developments in WO₃ based supercapacitor electrode materials have been discussed.

A biomaterial is any matter that has been fabricated to act with biological constitutions for a medical function-either a healing or an investigative one. The biomaterial area is about half a century old. The study of biomaterials is termed as either biomaterials science or biomaterials engineering. It has a skilled firm and potent growth over its history; with several corporates invest massive volumes of funds into the improvement of the most recent merchandises. Biomaterial science covers modules of materials science, chemistry, biology, medicine, and tissue engineering. A biomaterial is entirely diverse from a biological material, like bone, i.e., produced by a biological organization. Besides, care ought to be employed in tailoring a biomaterial as biocompatible, because it is application-specific. A biomaterial, i.e., biocompatible or appropriate for one application, might not be appropriate in other applications. In this book chapter, biomaterials are aiming to be classified as structural or purposeful and then the natural biological material is going to be correlated and differentiated with the biomaterials designed to substitute with it.

The rate of osseointegration of medical implants depends on their composition and surface roughness. Roughened surfaces can provide good biological activities with biomechanical stability. Calcium phosphate coatings promote bone apposition and healing that leads to rapid biological fixation of implants. In this chapter, surface treatments, namely grit blasting, laser-induced surface roughening, roughening of implants by anodization, chemical etching, cryogenic, hydrodynamic, and polymeric blasting, ultraviolet light treatment or calcium phosphate coatings, and their corresponding surface characteristics, are discussed. After the successful in vitro and in vivo tests, clinical studies on this issue with different implant surfaces are performed to develop implant surfaces having controlled and standardized topography. These investigations will be beneficial to understand the interactions between proteins, cells and tissues, and implant surfaces. This approach of surface roughening of titanium and their alloys should subsequently enhance the biological and mechanical properties of implants for their short-term as well as long-term applications.

With the arrival of nano-magnetism, a new dimension of advancement possibilities in the field of electrical engineering, electronics, optics, information technology, biomedical applications, etc. has been dawned upon us. In this chapter, we will start briefly discussing Magnetic materials, Nano-magnetism and the main features dominating magnetic properties of nanoparticles (MNPs) As magnetic properties of MNPs determine their fields of application, our concern in this chapter is also to introduce factors that need to be tuned for biomedical application. Later in application section, basic working principle, interaction between magnetic nanomaterial and static or alternating magnetic field, physical and chemical properties of MNPs preferred for particular application, and scope of improvisation have been briefed. Biomedical applications discussed here includes Targeted Drug delivery, Magnetic Bio-separation, Magnetic hyperthermia, MRI contrast enhancement, and Theragnosis.

Iron oxide/rGO nanocomposites are of great importance for its application in sensors, supercapacitors, electrical devices, drug delivery, etc. Due to their extremely good magnetic and electrical properties, they have been widely studied by researchers across the world. Also, the high surface to volume ratio and good adsorption properties makes it extremely useful for the sensing of various toxic chemicals. The properties of this composite depend upon the size and number of iron oxide nanoparticles distributed over the rGO sheet. Therefore, this chapter deals with the synthesis of iron oxide/rGO nanocomposites for its application in the sensing of various toxic chemicals. A detailed study has also been made on the sensing mechanism of various chemicals by iron oxide/rGO nanocomposites. This chapter is primarily helpful for the beginners to understand the synthesis procedures and sensing properties of iron oxide/rGO composites.

This chapter includes the synthesis of reduced graphene oxide (rGO) and its applications in the field of energy. rGO has gained fame in the scientific community because it has properties similar to graphene and can be easily manufactured in large scale. rGO is synthesized by reduction of graphene oxide (GO) using simple and efficient techniques like thermal, chemical, electrochemical and hydrothermal. rGO is used as electrode, hole transport layer as well as an electron transport layer in organic solar cells. It is also used as counter electrode in dye-sensitized solar cells. Additionally, rGO serves as electrode material for supercapacitor devices exhibiting high specific capacitance and cyclic stability values.

Photovoltaic received immense attention as the technology offers a clean, inexhaustible and cheap energy production applicable in a broad range. The basic working of a photovoltaic (PV) cell is summarized in this chapter. While silicon is the primary semiconducting material in the PV technology, recent developments are in the PV materials for cost-effective and better efficient materials. Various kinds of solar cells have developed in the past decade. Whereas various factors have affected the performance of a solar cell, photoanodes used in PV cells are the most critical component. This chapter deals with the investigation of various transparent conductive electrode (TCE) materials for photovoltaic applications that can replace indium tin oxide (ITO) which is the most widely used material because of its high transparency and excellent optoelectronic properties. Optical, electrical and power efficiency of various semiconductor Nanowire/Graphene nanocomposites are overviewed in this chapter.

Ion beam implantation is one of the widely used advanced technique for synthesis of nanomaterial. Ion-induced mechanism is the only technique in which both physical and chemical modification is possible simultaneously. Ion beam prompted nanomaterial synthesis is mainly passed through a number of phases viz. Supersaturation, Nucleation, Growth, Ostwald ripening, Coalescence, Burred layer, Annealing process etc. Again, the implantation process depends on various parameters such as material density, Charge state of ion, ion energy, ion fluence, ion flux or beam current, substrate temperature etc. Formation of a well ordered nanoclusters desired a well précised control over above parameters. In the present chapter the ion beam prompted synthesis has been evidently defined.

In this work, GaN-NWs were synthesized via vapor-liquid–solid (V-L-S) mechanism by chemical vapor deposition (CVD) technique using different metal catalysts, N₂ and H₂ flow rates. The (101) plane of GaN-NWs grown with Ni catalyst shift to higher diffraction angle indicates tensile stress whereas with Fe catalyst it shifts to lower diffraction angle indicates compressive stress. The FTIR spectrum of GaN-NWs grown with Ag, Fe, Ni and In catalysts revealed that 2E₁(TO) peak shows asymmetry to higher wavenumber region indicate another chemical compound of Ga=N or Ga–N–O with similar bonding strength overlap with each other. Raman spectrum of GaN-NWs with Ag, Fe, Ni, and In catalyst varying H₂ flow rates confirms that the intensity of A₁(TO) phonon peak with Ag catalyst increases with increasing H₂ flow rate indicates increasing polarizability of GaN-NWs due to change in dielectric constant of surrounding chemical environment. We have observed shorter phonon lifetime with Ni catalyst whereas longer phonon lifetime is observed with Fe catalyst. The room temperature photoluminescence spectra of GaN-NWs reveal several emission bands centered at 2.54, 2.69, 2.81, 2.89, and 2.94 eV, respectively. The integrated PL peak intensity decreases with increasing excitation energy above band gap indicates the non uniform distribution of defect states. XPS spectra of GaN-NWs reveal the presence of Ga(3d), Ga(3p), Ga(3s), C(1s), N(1s), at 20.3, 110.4, 162, 276, 398.3 eV, respectively.

PANI/graphene has been extensively studied as a sensing material for various gasses like H₂, CH₄, NH₃, many toxic gasses, etc. PANI and graphene show change in resistance during interaction with the gas molecules adsorbed by the surfaces. But when PANI/graphene makes composite, the surface area is increased which in turn increases the active sites for the adsorption of gasses due to which the sensitivity of the sensor enhances significantly than that of the individual materials. In this chapter, the sensing property of PANI/graphene in exposure to a few gasses such as H₂, NH₃, CH₄, and toluene has been discussed along with the simple method for synthesis of the material and some characterization studies.

Recently, graphene-based nanocomposites were reported by several researchers in various fields such as gas sensors, lithium-ion batteries, and photodetectors. The gas sensor is useful in detecting the harmful chemicals and toxic gases for the protection of human health and the environment. A recent, some researchers have reported that the gas sensors made of GO or rGO with the addition of metal oxide enhance the sensing properties of the sensor. In this context, attempts are made in reviewing various gas sensors based on graphene and its derivatives based metal-oxide nanocomposite exhibiting different sensing properties for different gases like NO₂, NH₃, H₂, LPG gas. Different synthesis methods and the results obtained from different characterization techniques for various gases were also discussed. Characterization techniques such as SEM, TEM, XRD, FTIR, UV, and CV were depicted.

Diamond-like carbon (DLC) thin films have many advantages like high wear resistance and hardness, low surface roughness, low friction coefficient, optical transparency, and chemical inertness. Due to these excellent properties, DLC thin films are used for an array of applications like lubricating layers on sliding parts, protective layers on magnetic media, and coating on biomedical implants, as antireflective coating. The main limitation of DLC thin film is its high internal stresses which often lead to a weaker adhesion to the substrates. This limitation can be overcome by the incorporation of different metals and semiconductors into the DLC film. Nowadays, a lot of research is going on the metal incorporated DLC films. The presented work is a summary of the mechanical and tribological properties of different metal incorporate DLC thin films.

Lithium ferrites are important ferrimagnetic materials that find wide applications in microwave devices. However, the preparation of stoichiometric lithium-based ferrites requires a high sintering temperature of ~1200 °C. At such temperature there is a great chance for loss of constituent materials such as lithia and oxygen, thus deviating from stoichiometry and hence the useful properties. If these systems could be prepared at temperature ≤1000 °C, there is a great chance to preserve their stoichiometry. To produce high-density stoichiometric lithium-based ferrites at lower temperatures use of sintering aids, liquid phase flux, glass, etc. may be employed. Different types of new and novel sintering techniques such as microwave and hybrid techniques may also be taken up to prepare these compositions. This chapter highlights different types of lithium-based ferrites prepared using additives and sintered at a lower temperature <1000 °C. The chapter further reports on the properties of such lithium-based ferrites.

Magnetite being a magnetic semiconductor has a large scope of applications in biomedication, catalysis, sensors, and magnetic devices. For various applications, one needs to characterize the stoichiometry, stability, and morphology. Various techniques exist for synthesizing magnetite, among all co-precipitation is favorable for industrial production. Industrial applications of magnetite nanoparticles may alter the stoichiometry, structure, and agglomeration due to the cyclic usage and exposure to environmental parameters such as heat, moisture, etc. To prevent the nanoparticles from such unwanted deterioration of the properties, composites of magnetite with suitable material can be prepared. Zeolite is one of the potential inorganic materials for making composites with magnetite.

The MXene family (i.e., the 2D metal carbides, nitrides, and carbonitrides) has gained tremendous interest among scientific community, to understand and tap the potential applications of this new, yet quickly, growing family. Although only about 30 MXenes have been reported so far, many more potential members have been predicted theoretically. There have been mounting efforts among scientific world to discover new MXenes. In this context, the exploration of new MXenes precursors (MAX phases) is the key. In fact, the fascinating physical and chemical properties of these materials pave the way for wide range of potential applications viz., battery technology and storage, photocatalysis, water purifications, biosensors, conductive coating, tribo-electric nanogenerators, superconductivity, etc. The present chapter focuses primarily on the various synthesis techniques, their applications in energy storage, environmental purpose, etc. This chapter also attempts to highlight some of the key unexplored yet potential research areas revolving around MXenes.

The increasing demands of materials in need due to the growing population has led to the search of new type of materials nowadays. ZIFs is one such material that belongs to a subclass of MOFs formed by imidazole linkers and metal ions which possess the characteristics of MOFs as well as Zeolites simultaneously. ZIFs have been used in many advance applications due to its unique properties like high porosity, functional tunability, high surface area, high thermal, and chemical stability. Photocatalysis is one of the applications of ZIFs which provides many benefits like degradation of organic pollutants, hydrogen production and antibacterial problems Commonly, MOFs and ZIFs exhibit very large band gaps due to the ultraviolet absorptive behavior. So, developing a photocatalyst which works under the visible-light irradiation will give us various advantages as ZIFs can enhance its functionality by forming composites or through doping of other metal or non-metal ions.

Although fossil fuel based polymers are useful in many ways, their raw materials are limited and they, undoubtedly, pollute our environment. The use of biopolymers and their nano-structured counterparts is one of the strategies to curb the problems of feedstock shortage and to create an eco-friendly environment. Furthermore, these biomaterials with their versatile properties provide much more and are found useful in many fields of science and technology, such as therapeutic drug delivery, cancer therapy, in enhancing mechanical properties of the biocomposites to mention a few.

The rapid growth in the demand for a high-performance energy storage device with high-speed recharging ability has drawn the attention of many researchers to designs and develop new materials for supercapacitor applications. Out of the developing nanotechnologies, nanofibers have achieved a great deal of attention in energy resources and electrical science, where their intriguing properties contribute to the product functionality. The graphene oxide-based electrospun nanofibers are promising materials for applications in energy storage devices and supercapacitors due to the unique properties such as outstanding electrical conductivity, highly tunable surface area, excellent mechanical behavior, and good chemical stability. In this chapter, the authors give a brief introduction of the supercapacitor and discuss the structure and properties of GO, along with adequate explanation and insights toward the method for the fabrication of electrospun nanofibers. The conclusion section will discuss the electrochemical performance of functionalized graphene oxide-based electrospun nanofibers electrode for supercapacitor applications.

Nanotechnology becomes an emerging concept and plays an important role in medical science particularly in drug delivery during the treatment of serious sickness. The responses of the nanowire to an electromagnetic field generated by a separate device can be used to control the release of a preloaded drug. This system eliminates tubes and wires required by other implantable devices that can lead to infection and other complications. This tool also allows applying drugs as needed directly to the site of injury. This technology has tremendous potential to improve the precision of lung cancer therapy and has become a key technology in the development of more powerful pharmaceutical treatments against cancer. Nanomedicine products can, be loaded with chemotherapeutic agents and specifically targeted to the tumor site, thus decreasing the side effects and increasing the therapeutic effect of the drugs. Particularly, silver nanomaterials can find many remarkable applications in clinical practice since they possess optimal chemical reactivity for the functionalization of their surfaces with biologically active moieties.

The world is changing rapidly advancing towards the development of technology. The scope within the field of medical sciences has also evolved with the advancement of technology. The following content will focus on the art of nanoparticle and applications of nanodevices in the field of medical diagnosis and treatment of diseases. Several highly sensitive disease detectors and diagnostic devices have been integrated with nanodevices. The devices are found to be stable over long periods of time and have display reliable performance properties. For therapeutic purposes additionally, nanotechnology strategies have also been applied. As an example, to guard drugs against degradation, nanoparticle-based delivery systems are developed, thereby reducing the specified dose and dose frequency, improving patient comfort and convenience during treatment, and reducing treatment expenses. The content will review the main objectives for integrating nanotechnologies in the field of medical diagnosis and treatment of diseases.

Lithium-ion batteries (LIBs) as efficient energy storage and ingenious energy conversion own the major power source in the consumer portable electronics of the revolutionized digital world. Electrode materials utilized in LIBs play dominant roles in the development of high-performance LIBs. Intensive research for new cathodic and anodic materials has been conducted substantially in the last two–three decades for high-capacity LIBs maintaining safety and cost-effectiveness to satisfy the needs of the growing demand for large capacity electric vehicles. Ternary metal oxides/graphene nanocomposites-based LIBs are recently investigated as anode materials for their synergistic effect exhibition with enhanced capacity, rate capability, and stable cycling. The chapter highlights the basics, electrochemical reactions involved, progress and challenges, different anode materials, and their electrochemical performance of LIBs. Herein, ternary metal oxides/graphene nanocomposites are particularly discussed as anodic materials for LIBs while dealing with the composite preparation, contributions of individual counterparts in the overall performance, and proposed strategies to circumvent the challenges faced in order to realize next-generation LIBs.

The cotton-based graphene supercapacitors are of great importance mainly due to their high stability, low cost, fast charging/discharging, and high efficiency, properties that render them value for developing fully flexible and lightweight devices. At recent, some researchers have reported on the cotton@graphene-based composites used for flexible electrodes obtaining good capacitance, excellent mechanical flexibility, and good stability which considered it as a potential candidate for flexible supercapacitor application. In this chapter, the different synthesis methods of cotton@graphene-based nanomaterials have been described and the previously reported works on lightweight flexible supercapacitor electrodes based on cotton@graphene composite were overviewed. Further, the morphology, chemical bonding, composition, defects, and electrochemical properties of cotton@graphene composite fabrics obtained from different characterization techniques were also presented.