physics Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which r ...

electrical engineering Electrical engineering is an engineering discipline concerned with the study, design, and application of equipment, devices, and systems which use electricity, electronics, and electromagnetism. It emerged as an identifiable occupation in the l ...

and materials science, electromaterials are the set of materials which store, controllably convert, exchange and conduct electrically

charged particle In physics, a charged particle is a particle with an electric charge. It may be an ion, such as a molecule or atom with a surplus or deficit of electrons relative to protons. It can also be an electron or a proton, or another elementary particle, ...

s. The term electromaterial can refer to any electronically or ionically active material. While this definition is quite broad, the term is typically used in the context of properties and/or applications in which

atomic electronic transition Atomic electron transition is a change (or jump) of an electron from one energy level to another within an atom or artificial atom. It appears discontinuous as the electron "jumps" from one quantized energy level to another, typically in a few n ...

is pertinent. The word electromaterials is a compound form of the

Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic peri ...

term, ἤλεκτρον ēlektron, "

Amber Amber is fossilized tree resin that has been appreciated for its color and natural beauty since Neolithic times. Much valued from antiquity to the present as a gemstone, amber is made into a variety of decorative objects."Amber" (2004). In Ma ...

", and the Latin term, materia, "

Matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects that can be touched are ultimately composed of atoms, which are made up of interacting subatomic partic ...

Properties

Electromaterials enable the transport of charged species (

electrons The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no ...

and/or

ions An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conven ...

) as well as facilitate the exchange of charge to other materials. For

atom Every atom is composed of a nucleus and one or more electrons bound to the nucleus. The nucleus is made of one or more protons and a number of neutrons. Only the most common variety of hydrogen has no neutrons. Every solid, liquid, gas, and ...

ic and

molecule A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bioch ...

systems, this is observed as

between discrete orbitals, while for bulk

semiconductor A semiconductor is a material which has an electrical resistivity and conductivity, electrical conductivity value falling between that of a electrical conductor, conductor, such as copper, and an insulator (electricity), insulator, such as glas ...

materials electronic bands determine which transitions may occur. Metals, in which the conduction band is permanently populated, may also be considered electromaterials, although this is typically outside the category compared to other conduction mechanisms such as for a

degenerate semiconductor A degenerate semiconductor is a semiconductor with such a high level of doping that the material starts to act more like a metal than as a semiconductor. Unlike non-degenerate semiconductors, these kind of semiconductor do not obey law of mass act ...

(transparent conductive oxides) or

polaron A polaron is a quasiparticle used in condensed matter physics to understand the interactions between electrons and atoms in a solid material. The polaron concept was proposed by Lev Landau in 1933 and Solomon Pekar in 1946 to describe an electro ...

hopping ( organic conductor). Materials which can be ionised (i.e. electrons either added or stripped away) may also be considered electronically active. Electromaterials have a number of properties broadly, including: * Opto-electronic properties * Photoelectric propertiesSariciftci, N. S., Smilowitz, L., Heeger, A. J. & Wudl, F. Photoinduced electron transfer from a conducting polymer to buckminsterfullerene. Science 258, 1474–1476 (1992)

* Exotic phenomena such as super-conductive properties * Partial charge transfer, adsorption of species leading to change in electronic properties of material * Ion conductive materials

Applications

In the application of electromaterials, ions or electrons are used to carry out a specific function. For example, the

oxidation Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a d ...

or reduction (loss or gain of electrons, respectively) of another species. Materials such as metals, metal particles, conducting polymers, conducting carbon, e.g. CNTs, graphene, carbon fibres, electrodes, electrolytes, electrocatalysts, light harvesting materials (e.g. dyes for DSSCs) find applications in which electromaterials are critical to their functionality: * Batteries * Super-capacitors *

Fuel cell A fuel cell is an electrochemical cell that converts the chemical energy of a fuel (often hydrogen) and an oxidizing agent (often oxygen) into electricity through a pair of redox reactions. Fuel cells are different from most batteries in requ ...

s *

Photovoltaics Photovoltaics (PV) is the conversion of light into electricity using semiconducting materials that exhibit the photovoltaic effect, a phenomenon studied in physics, photochemistry, and electrochemistry. The photovoltaic effect is commercially us ...

Artificial muscle Artificial muscles, also known as muscle-like actuators, are materials or devices that mimic natural muscle and can change their stiffness, reversibly contract, expand, or rotate within one component due to an external stimulus (such as voltage, ...

s * Chemical sensors * LEDs * Energy conversion/storage devices * Systems that interact with living tissue and soft robotics (prosthetics)

Characterisation

Electromaterials can be explored by techniques such as (but not limited to)

absorption spectroscopy Absorption spectroscopy refers to spectroscopic techniques that measure the absorption of radiation, as a function of frequency or wavelength, due to its interaction with a sample. The sample absorbs energy, i.e., photons, from the radiating fie ...

, photoluminescence spectroscopy, electrochemistry, FTIR,

Raman spectroscopy Raman spectroscopy () (named after Indian physicist C. V. Raman) is a spectroscopic technique typically used to determine vibrational modes of molecules, although rotational and other low-frequency modes of systems may also be observed. Raman sp ...

or combinations of the above, such as raman spectroelectrochemistry.

References

{{reflist Electricity Materials science

Properties

Applications

Characterisation

See also

References