Nanomaterials are nanostructures that have gained massive interest in the scientific community due to their exciting functional and physicochemical properties. They offer high stability, advanced optical-electronic properties, and tuneable surface functionalization. Such properties have made them a material of everyday use in the pharmaceutical industries, cosmetics, electronics, and many more. Considering their increasing usage, there is a demand for reliable and better quantitative and qualitative characterization tools. This chapter is dedicated to such characterization methodologies for the analysis of nanomaterials. Numerous distinct and integrated correlated techniques are discussed in detail. Such tools are arranged from the basic to advanced methods, each mentioning the unique property of nanomaterial such as elemental composition, morphology, crystal structure, magnetism, and strength. Lastly, some recent advancements in the characterization methodologies of nanostructures are provided. Understanding the properties of nanomaterials will enable us to expand their applications in society.
TopIntroduction
“Why cannot we write the entire 24 volumes of the Encyclopaedia Britannica on the head of a pin?” Richard Feynman from the historical lecture, ‘There’s Plenty of Room at the Bottom’ in 1959 (Geoff, 1960).
Richard Feynman, the pioneer of science and technology, painted the first canvas of the nanoscale. Sixty-two years from then, today, we have not only maneuvered things at the length scale of an atom but have developed a whole new discipline of science called Nanoscience and Nanotechnology. Although the first paper in this area was published in 1981 by Eric Drexler, the real breakthrough came only in 1989 after the development of a scanning tunneling microscope (STM) by Binnig, Gerber, and Quate at IBM Zurich, Switzerland. Soon after, nanotechnology got spread throughout the world, encompassing every sphere of our life, from medicine to industries. Nanomaterials refer to functional materials developed on the concept of nanotechnology, whose dimensions range from 1 to 100 nm. They have gained considerable interest among scientists because of their exclusive optical, magnetic, electronic, and physicochemical properties. They have also become an integral part of nanoscience and nanotechnology not only because of their functional properties but also due to their future technological applications in various fields such as sensors, bioimaging, catalysis, optoelectronics, photothermal therapy, water purification, drug-gene delivery, cosmetics, lab-on-chip devices, energy harvesting, etc. (Stancheva, 2012; Toropov & Vartanyan, 2019; Vajtai, 2013). The considerable demand for novel nanomaterials opens the challenge for their accurate and reliable characterization techniques.
Recently, various characterization tools and methodologies have been developed to identify and specify the elemental composition, size, shape, crystal structure, surface charge, and other physicochemical properties of nanomaterials. An individual characterization tool is often insufficient to describe the complete nature of nanomaterials. In that case, a combinatorial approach of techniques and methodologies is required for the detailed analysis of such functional nanomaterials. However, a complete characterization of nanomaterials is still a challenging task to accomplish. Some of the limitations associated with the incomplete characterization of nanomaterials are; 1) The size, shape, and morphology of nanomaterials generally vary from bulk materials to the single-dimension level; 2) The inaccessibility of every research lab to have quick and easy access to diverse characterization facilities. In the study of nanomaterials, analytical targets and characterization tools are employed right from the stage of synthesis to the determination of morphology, understanding surface functionalization, and other physicochemical properties. In this chapter, the focus will roam around different standard, complementary, and specific techniques such as absorption spectroscopy, transmission electron microscopy, X-ray crystallography, etc. for the analysis of the distinct nanomaterials. Besides the characterization tools, the weaknesses, and the strengths associated with the analysis are also mentioned in brief.
Towards the end, few recent advancements and the present state-of-art in characterization methodologies are reflected. Cryo-transmission electron microscopy (cryo-TEM), electron tomography (ET), and tip-enhanced Raman spectroscopy (TERS) are some of the cutting-edge techniques developed lately, which have gained immense popularity due to their enhanced resolution and improved sampling conditions. The timeline of characterization techniques is illustrated as a flowchart in Figure 1.
Accounting for the importance of nanomaterials in society, this book chapter is well-organized focusing on their characterization tools. Hence, different aspects have been focused on 2D materials, nanoparticles (NPs), quantum dots, and so forth with their futuristic applications in diverse fields.
TopBackground
Analytical tools with a high spatial and temporal resolution are crucial for understanding the synthetic aspects, architecture, various physicochemical properties, and surface chemistry of nanomaterials. Several characterization tools such as absorbance, fluorescence, dynamic light scattering (DLS), surface-enhanced Raman spectroscopy (SERS), mass spectrometry (MS), and so forth have been routinely used for the analysis of nanomaterials. These experimental characterization techniques can be classified broadly on the following aspects: