What is Materials Science?

Recent business news reports “Materials Science” as the next big thing in scientific research today.

So what is Materials Science? What are its uses and applications? How is materials science important to the future of high technology, climate change, and space exploration?

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Plainly put, materials science is the modern scientific study of what once was called alchemy. Both disciplines attempt to understand the structure and composition of basic natural substances such as elemental metals and minerals and using that knowledge to create entirely new types of materials with novel properties and applications. In the middle ages, alchemy was the province of sorcerers. Today, we think of names like Albert Einstein, Elon Musk, who earned a PhD in energy physics/materials science at Stanford University and Google CEO Sundar Pichai, who holds a Master’s degree in materials science from Stanford University.

Materials Science is now an interdisciplinary field, drawing on many academic areas such as chemistry, physics, biology, engineering, metallurgy, and more. By teasing out new and unexpected properties of the basic elements, materials scientists have discovered everything from nuclear energy to wireless communication to solar panels to computers, all by intellectually “mining” the properties of that rectangular stack of little boxes we call the Periodic Table. All of nature and all of its yet-to-be-discovered properties that will sustain humanity for the long term are found therein. That’s why we say materials science is all about thinking INSIDE the box.


Fundamental Concepts of Materials Science

"The Three P's"

Purity

American Elements grown ultra high purity crystals for solar energyFor many high-tech and scientific applications, the physical and chemical properties of materials must be both highly reliable and constrained within very narrow parameters. The exact properties of interest often vary by application, but what many such properties have in common is that they are exquisitely sensitive to minor variations in the precise chemical composition of a material. Impurities present even as fractions of a percentage of the makeup of an otherwise pure material can drastically alter how the material as a whole conducts electricity, interacts with light, reacts chemically with other compounds, or stands up to environmental damage. For these reasons, raw materials of exceptional purity are absolutely essential in many fields. Techniques such as crystal growth and other methods produce high and ultra high purity materials - up to 99.99999% pure - with critical element impurities in the lowest ppb (parts per billion) range. Sophisticated and exact analysis methods such as X-ray diffraction (XRD), scanning electron microscopy (SEM), glow discharge mass spectroscopy (GDMS), and BET surface area analysis verify the elemental composition and structural properties of materials, ensuring their optimal performance.

Nickel Cermet NanoparticlesAmerican Elements manufactured nanoparticles for Z-Mite™ nanopowder

Particle Size

In his seminal 1959 lecture "There’s Plenty of Room at the Bottom”, Richard Feynman laid the groundwork for the field of nanotechnology by considering the possibility of manipulating materials on the atomic scale. In the subsequent years, researchers discovered techniques to synthesize smaller and smaller particles, from micron (µm) down to the nanometer (nm) scale. These minuscule particles known as nanoparticles exhibit unique mechanical, optical, and electronic properties, introducing an enormously greater range of possible material characteristics than are achievable through conventional, macro or even micro scale engineering. Nanomaterials utilized across wide-reaching fields of industry and research, from bioengineering and advanced microelectronics to commercial product manufacturing. For example, American Elements Z-Mite™, zinc oxide nanoparticles used for its UV absorbing properties to create transparent but highly effective sunscreen. Nanotechnology is a continually advancing field with limitless possibilities for the future - such as developing additive manufacturing methods which can construct materials from the atomic level up.

Periodic Table

The fundamental building blocks of materials science are the elements themselves. A chemical element is defined by the number of protons in its nucleus, increasing in number (and atomic weight) as one goes down the table. Hydrogen, at the top of the table, is the lightest element, with only a single proton; the heaviest naturally occurring element, Plutonium, has two hundred and forty four. Scientists are also capable of synthesizing heavier “artificial” elements in nuclear laboratories, all of which are radioactive and decay quickly. At this point in time, 24 synthetic elements have been produced up to element 118 (Oganesson), with 294 protons; as technology advances, even more elements may end up being added to the table!

Period Table of the Elements

The elements make up our entire world, from the air we breathe to the cars we drive. Traditional scientific disciplines such as chemistry explore how and why the elements behave as they do, both individually and in combination with others. Materials science goes further, finding new ways to manipulate and combine elements and to exploit the more unusual electrical, magnetic, and optical properties of larger elements like the rare earths. For example, doping and intercalation are methods that insert individual atoms into the crystal structure of a material such as a semiconductor, imparting entirely new properties.


Novel Types of Materials

  • Semiconductors. Semiconductors are materials with electrical conductivities between that of a metal and an insulator, but their true value in electronic devices lies in the ability of their conductivity to be easily manipulated. Current conduction in a semiconductor occurs due to the movement of charge carriers: free electrons carry negative charge, while the spaces left behind when electrons move, often termed "holes", carry positive charge. The inherent electrical properties of a semiconducting material can be manipulated by doping the material with elemental impurities, which greatly increases the number of charge carriers available to conduct a current. The most well-known semiconductor elements are silicon and germanium, but materials scientists are discovering and engineering new semiconducting materials such as quantum dots every day.
  • Nanomaterials. The variety of nanoscale structures extends far beyond the simple nanoparticle. From elongated particles like nanotubes and nanowires to increasingly exotic structures such as nanohoops, nanopyramids, nanocubes, and buckyballs, there is no limit to the type of shape nanomaterials can take. One of the most important type of nanomaterial is a two-dimensional atomically thin layer of carbon atoms arranged in a hexagonal lattice - graphene. Graphene is both incredibly strong and thin, with exceptional thermal conductivity, electron mobility, opacity to light, and surface area.
  • Organometallics. Also known as metalorganics, these molecules consist of a metallic element covalently bonded to a carbon atom in a type of hybrid organic-inorganic composition. These are synthetic materials with numerous applications, notably as catalysts and precursors for thin film deposition and the synthesis of semiconductors and nanomaterials.
  • Perovskites. Perovskite materials possess the same crystal structure as the mineral of the same name with formula CaTiO3 (calcium titanate). Perovskites have many interesting properties such as superconductivity, colossal magnetoresistance, ionic conductivity, ferroelectricity, and various dielectric properties. These materials are of interest for perovskite solar cells, a novel high-efficiency, low cost alternative to current photovoltaic cells.
  • MXenes. Mxenes (pronounced "max-enes") are a novel type of two-dimensional (2D) ceramic material composed of layered nitrides, carbides, or carbonitrides of transition metals. MXenes are notable for their properties that combine aspects of both metals and ceramics. These include excellent thermal and electrical conductivity, heat resistance, easy machinability, and excellent volumetric capacitance, having the highest EMI shielding effectiveness of all similar synthetic 2D materials, and hydrophobic natures due to various surface functional groups. MXenes have applications in advanced battery and energy storage technologies such as lithium-ion, sodium-ion, and supercapacitors, water purification, electromagnetic shielding, photocatalysis, gas sensors, optoelectronics, polymer nanocomposite fillers, and conductive coatings. In many cases MXenes have been shown to outperform other 2D materials such as graphene.

  • MOFs. MOFs, or metal-organic frameworks, have elemental compositions similar to organometallic compounds but with larger and more complex molecular structures consisting of metallic ions bonded to organic ligands. MOFs are porous, high surface-area materials that are exceptionally efficient electrocatalysts for splitting water and carbon dioxide reduction. They are highly efficient gas adsorbers, making them prime candidates for hydrogen storage technologies, carbon capture, and other green technology applications.

Uses & Applications for Materials Science

Green Technology & Alternative Energy

Materials science has revolutionized the field of green technology, offering new processes, practices, sources of energy to power our lives that are more efficient and substantially decrease our impact on the environment.

Battery Technology

High energy density lithium-ion (Li-I) batteries are the current hi-tech standard in the computing and electronics. The central mechanism by which the battery stores and generates energy is the reversible intercalation, or insertion, of lithium ions in the crystalline electrode materials; the positively-charged Li+ ions shuttling between the cathode (typically a lithium compound or mixed metal oxide) and the anode (typically graphitic carbon) through the electrolyte and separator membrane. Lithium Ion BatteryBecause of the high reactivity of lithium metal with water, non-aqueous electrolyte formulations are required, typically lithium salts like LiPF6 in an organic solvent. Types of Li-ion batteries are known by their cathode materials, the most common being lithium cobalt oxide (LCO), lithium manganese oxide (LMO), lithium iron phosphate (LFP), and lithium nickel manganese cobalt oxide (NMC). Two other chemistries that are gaining attention for transportation and grid energy storage applications are lithium nickel cobalt aluminum oxide (NCA), used as a cathode, and lithium titanate (LTO), used as an anode material replacing graphite.

The current generation of lithium-ion batteries suffers from certain limitations to electrochemical performance that arise from its design, from the low conductivity of oxide-based cathode materials and insulating tendencies of electrolyte binders to the formation of dendrites at the surfaces of the electrode-electrolyte interface. Added to safety concerns based on the high reactivity of lithium metal, and the flammability and toxicity of electrolyte formulations, researchers are focusing on developing alternative designs that either improve existing lithium-ion technology or propose commercially viable alternative technologies. Some substitutes for electrode materials include lithium vanadium oxide and lithium vanadium phosphate. Alternative chemistries to the lithium-ion paradigm include lithium-sulfur, sodium sulfur, sodium ion, lithium-air, nickel-lithium, and vanadium redox (flow) batteries. In addition many novel experimental battery designs are under investigation that rely on advanced materials like copper antimonide nanowires, tin oxide nanocrystals, vanadium dioxide ribbons paired with graphene, and carbon nanotubes.

Fuel Cells

As the global demand for green energy sources continues to rise, the advancement of fuel cell design plays a critical role in the development of viable alternatives to fossil fuel-based technologies for portable, stationary, and grid-scale power generation and storage. Unlike batteries, which generate power from internally-stored electrochemical energy, fuel cells require the continuous input of a hydrogen-based fuel source in order to produce electricity. Fuel cells possess the advantage of being able to operate indefinitely, in theory, and can be fully discharged without suffering voltage disruptions or degradation of internal components.

Solid Oxide Fuel Cell

Solid oxide fuel cells (SOFCs) use all solid components: the most common design uses yttria stabilized zirconia as the electrolyte, nickel-ceramic composites (cermets) for anodes, and lanthanum strontium manganite for cathodes. The use of all solid materials is the key defining feature of these cells, as it allows for the development of cell designs that are incompatible with the use of liquid electrolytes. SOFCs can run on a variety of fuels, including hydrocarbons and pure hydrogen gas, and require high operating temperatures regardless of fuel type. The high temperature is necessary for the solid electrolyte to achieve high enough conductivity for optimal cell performance. Solid oxide fuel cells are currently being used or considered for use in auxilary power, electric power plant, and distributed generation applications.

Polymer electrolye membrane fuel cells (PEMFCs), also known as proton exchange membrane fuel cells, are a class of fuel cells being developed for both transportation and stationary applications. They are a lower temperature fuel cell and feature a special polymer membrane which serves as the electrolyte. The chemistry which produces the energy in all PEMFC cells is hydrogen-based, but some cell designs use hydrogen directly, while others are designed for use with hydrogen-heavy organic molecules. Advantages of PEMFC fuel cells include quick startup times, low operating temperature, and the durability and design advantages inherent to using a solid rather than liquid electrolyte. However, the catalysts they require make them expensive to build and they are sensitive to fuel impurities. Additionally, the low operating temperature of PEMFCs, while advantageous in some respects, does make using their waste heat to increase overall system efficiency impractical. PEMFCs are currently mostly of interest for transportation applications, or for short-term stationary applications, such as to serve as a backup power source.

Solar Energy

Photovoltaics constitute the fastest growing segment of the modern energy market, and for good reason. Photovoltaic systems are clean, produce electricity directly, and are scalable to meet the demands of a vast range of applications. Photovoltaic Solar PanelsThe most prominent materials used in the current generation of solar cells are Copper Indium Selenide (CIS)/Copper Indium Gallium Selenide (CIGS) and Cadmium Telluride (CdTe). Both cell types use the material they are named for as the p-type sunlight-absorbing layer, while cadmium sulfide is used as the n-type later. Both cell types boast significantly higher absorptivity than silicon, allowing for the use of much thinner material layers. However, technologies suffer from some issues with material toxicity and scarcity: cadmium is a toxic heavy metal, tellurium is as rare as gold, and indium is subject to supply problems related to the enormous demand for indium tin oxide for transparent electrodes.

While first and second generation solar cells typically use conventional semiconductor materials and designs dependent on single large-area p-n junctions to produce current, the next generation of solar technology uses radically different materials and cell designs for new approaches to lowering cost while maintaining reasonable cell efficiencies in addition to using more environmentally friendly materials. Polymer or organic photovoltaics (OPV) and dye-sensitized solar cells (DSSCs) are two promising candidates to become commercially viable alternatives to These cell types are of particular interest due to their ability to be fabricated very simply--the polymers lend themselves to roll-to-roll printing methods, allowing for extremely efficient and cheap production. Perovskite solar cells (PSCs) are another promising technology under development which uses perovskite-structured materials like hybrid organic-inorganic tin, cesium, or lead halides (such as methylammonium lead iodide). These cells possess the advantage of being simple and inexpensive to produce, while being tolerant to internal defects.

Additive Manufacturing & 3D-Printing

The old ways of "making stuff" pale in comparison to the efficiency of the newest method of creation--additive manufacturing, also known as 3D-printing. Once limited to building smaller objects using polymers, additive manufacturing now has an increasing range of source materials available such as from metal, alloy, and ceramic powders to construct large scale-objects layer-by-layer. The advantage of 3D printing is low volume production, conserving materials to fabricate only what is needed (known as "rapid prototyping"), thus conserving time and eliminating waste. Additive manufacturing can produce objects from advanced medical prostheses to aerospace and automotive parts; future applications may extend to the nanoscale, allowing for atomic level building.

Optical Materials & Lighting

Laser

From laser crystals to LEDs, advanced optical materials are ubiquitous in the field of high technology. Through materials science, the oldest and most well-known optical material, glass, can be made bulletproof, shatterproof, touch sensitive, electrically conductive, and responsive to fluctuations in light and temperature. Rare earth elements are particularly versatile in optical materials; cerium oxide is one of the most effective materials for precision polishing, and oxides of neodymium, praseodymium, and lanthanum are used to impart both colors and additional properties to glasses such as infrared absorption (used in night-vision goggles). The rare earths are also important dopants in laser crystals. Nd:YAG (neodymium-doped yttrium aluminum garnet) lasers are one of the most common types, used in dentistry, medicine, and defense, although YAG lasers can be doped with other rare earths including erbium, ytterbium, and thulium, or transition metals like chromium. Doping with different elements yields gain mediums that lase at different wavelengths, giving them applications as phosphors or scintillators. Light-emitting diodes (LEDs) are are solid-state lighting devices composed of semiconductors like Gallium Nitride (GaN) used in energy-efficient light bulbs and display screens for electronic devices like televisions and smartphones. Development is underway to produce LEDs from alternate materials to improve efficiency and performance, particularly brightness and color quality. Examples of next-generation types of LEDs are those that use organic semiconductors (OLEDs) and quantum dots (QLEDs).

Thin Film Deposition

The history of applying thin metallic coatings to surfaces spans hundreds of years, from the experiments of Thomas Edison and the rise of metal plating during World War II to the present. Now, the various techniques of the process known as thin film deposition are crucial to all fields of high technology including the fabrication of integrated circuits, semiconductor crystals, and nanomaterials. "Depositing" the thinnest layers of materials is achieved via physical or chemical methods including "sputtering," which involves controlled removal and conversion of the target material into a directed gaseous/plasma phase through ionic bombardment.

Satellite

Space-based Materials

Materials science is the foundation of one of humanity's greatest achievements--space exploration. Outer space is the harshest imaginable environment, requiring materials that can withstand the intense heat of entering and exiting earth's atmosphere to the constant bombardment from solar radiation. Ultrawhite anti-reflective coatings created from high purity oxides, refractory structural alloys made from aluminum and beryllium that are both ultra strong and ultra light , and parts made from iridium (the lowest corroding metal known) have become the standard for constructing spacecraft and satellites.


MATERIALS SCIENCE RESOURCES

Careers in Materials Science

What can I do with a materials science degree?

There is a wealth of career opportunities available to graduates with materials science degrees. Below are a few of the best jobs for MSE graduates:

  • Materials Engineer
  • Research Scientist
  • Metallurgist
  • Process Engineer
  • Technical Sales Engineer
  • Manufacturing Engineer
  • Biotechnology Engineer
  • Pharmaceutical Development
  • and more!

American Elements is always hiring! To apply for a job or internship, click here.