A material is a chemical substance or mixture of substances that constitute an object. Materials can be pure or impure, a singular composite or a complex mix, living or non-living matter, whether natural or man-made, either concrete or abstract. Materials can be classified based on different properties such as physical and chemical properties (see List of materials properties), geological, biological, choreographical, or philosophical properties. In the physical sense, materials are studied in the field of materials science.
In industry, materials are inputs to production or manufacturing processes. They may either be raw material, that is, unprocessed, or processed before being used in more advanced production processes, either by distillation or synthesis (synthetic materials).
Types of materials include:
Materials are classified according to many different criteria including their physical and chemical characteristics as well as their intended applications whether it is thermal, optical, electrical, magnetic, or combined. As their methods of usage dictate their physical appearance, they can be designed, tailored, and/or prepared in many forms such as powders, thin or thick films, and plates and could be introduced/studied in a single or multi layers. End products could be pure materials or doped ones with most useful compounds are those with controlled added impurities.The dopants could be added chemically or mixed and implanted physically. In case the impurities were added chemically, the dopants/co-dopants on substitutional/interstitial sites should be optimized and investigated thoroughly as well as any stresses instigated by their presence within the structure; whereas in the case of the physical mixing, the influence of the degree of heterogeneity of the prepared hybrid composites ought to be studied.The different physical and chemical preparation techniques can be used solely or combined including solid state synthesis, hydrothermal, sol-gel, precipitations and coprecipitations, spin coating, physical vapor deposition, and spray pyrolysis. Types of impurities along with their amounts are usually dictated by types of matrices to be added to, and their ability to maximize the desired products' usefulness. Among the most commonly used characterization techniques are X-ray diffraction (XRD) either single crystal or powder, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray fluorescence (XRF), differential scanning calorimetry (DSC), UV-Vis absorption Spectroscopy, Fourier transform infra-red (FTIR), and Photoluminescence spectrometry. In addition, it is usually considered of extreme importance to find theoretical models that can confirm and/or predict the experimental findings and assist in discussion, assignment, and the explanation of results and outcomes. Also, vision and room for future modification and development should always be pinpointed. Hence, one can classify the material as a smart one if its presence can serve multi purposes within the final product.