What is the largest indigenous tribe in Canada?

The Ojibwe, Ojibwa, Chippewa, or Saulteaux are an Anishinaabe people of Canada and the United States. They are one of the largest indigenous peoples north of the Rio Grande. In Canada, they are the second-largest First Nations population, surpassed only by the Cree. In the United States, they have the fifth-largest population among Native American peoples, surpassed in number only by the Navajo, Cherokee, Choctaw and Sioux.

Ojibwe

The Ojibwe people traditionally speak the Ojibwe language, a branch of the Algonquian language family. They are part of the Council of Three Fires and the Anishinaabeg, which include the Algonquin, Nipissing, Oji-Cree, Odawa and the Potawatomi. Historically, through the Saulteaux branch, they were a part of the Iron Confederacy, joining the Cree, Assiniboine and, Metis.
The majority of the Ojibwe people live in Canada. There are 77,940 mainline Ojibwe; 76,760 Saulteaux; and 8,770 Mississauga, organized in 125 bands. They live from western Quebec to eastern British Columbia., Ojibwe in the US census population is 170,742.

The Ojibwe are known for their birch bark canoes, birch bark scrolls, mining and trade in copper, as well as their cultivation of wild rice and Maple syrup. Their Midewiwin Society is well respected as the keeper of detailed and complex scrolls of events, oral history, songs, maps, memories, stories, geometry, and mathematics.

The Ojibwe people set the agenda with European-Canadian leaders by signing detailed treaties before they allowed many European settlers into their western areas.

The exonym for this Anishinaabe group is "Ojibwe" (plural: "Ojibweg"). This name is commonly anglicized as "Ojibwa" or "Ojibway". The name "Chippewa" is an alternative anglicization. Although many variations exist in literature, "Chippewa" is more common in the United States, and "Ojibway" predominates in Canada, but both terms are used in each country. In many Ojibwe communities throughout Canada and the U.S. since the late 20th century, more members have been using the generalized name "Anishinaabe(-g)".

The exact meaning of the name "Ojibwe" is not known; the most common explanations for the name derivations are:

Because many Ojibwe were formerly located around the outlet of Lake Superior, which the French colonists called Sault Ste. Marie for its rapids, the early Canadian settlers referred to the Ojibwe as "Saulteurs". Ojibwe who subsequently moved to the prairie provinces of Canada have retained the name Saulteaux. This is disputed since some scholars believe that only the name migrated west. Ojibwe who were originally located along the Mississagi River and made their way to southern Ontario are known as the Mississaugas.

The Ojibwe language is known as "Anishinaabemowin" or "Ojibwemowin", and is still widely spoken, although the number of fluent speakers has declined sharply. Today, most of the language's fluent speakers are elders. Since the early 21st century, there is a growing movement to revitalize the language, and restore its strength as a central part of Ojibwe culture. The language belongs to the Algonquian linguistic group, and is descended from Proto-Algonquian. Its sister languages include Blackfoot, Cheyenne, Cree, Fox, Menominee, Potawatomi, and Shawnee among the northern Plains tribes. "Anishinaabemowin" is frequently referred to as a "Central Algonquian" language; Central Algonquian is an area grouping, however, rather than a linguistic genetic one.

"Ojibwemowin" is the fourth-most spoken Native language in North America (US and Canada) after Navajo, Cree, and Inuktitut. Many decades of fur trading with the French established the language as one of the key trade languages of the Great Lakes and the northern Great Plains.

The popularity of the epic poem "The Song of Hiawatha", written by Henry Wadsworth Longfellow in 1855, publicized the Ojibwe culture. The epic contains many toponyms that originate from Ojibwe words.

According to Ojibwe oral history and from recordings in birch bark scrolls, the Ojibwe originated from the mouth of the St. Lawrence River on the Atlantic coast of what is now Quebec. They traded widely across the continent for thousands of years as they migrated, and knew of the canoe routes to move north, west to east, and then south in the Americas. The identification of the Ojibwe as a culture or people may have occurred in response to contact with Europeans. The Europeans preferred to deal with bounded groups and tried to identify those they encountered.

According to Ojibwe oral history, seven great "miigis" (radiant/iridescent) beings appeared to them in the "Waabanakiing" (Land of the Dawn, i.e., Eastern Land) to teach them the "mide" way of life. One of the seven great "miigis" beings was too spiritually powerful and killed the people in the "Waabanakiing" when they were in its presence. The six great "miigis" beings remained to teach, while the one returned into the ocean. The six great "miigis" beings established "doodem" (clans) for people in the east, symbolized by animal, fish or bird species. The five original Anishinaabe "doodem" were the "Wawaazisii" (Bullhead), "Baswenaazhi" (Echo-maker, i.e., Crane), "Aan'aawenh" (Pintail Duck), "Nooke" (Tender, i.e., Bear) and "Moozoonsii" (Little Moose), then these six "miigis" beings returned into the ocean as well. If the seventh "miigis" being had stayed, it would have established the Thunderbird "doodem".

At a later time, one of these "miigis" appeared in a vision to relate a prophecy. It said that if the Anishinaabeg did not move further west, they would not be able to keep their traditional ways alive because of the many new pale-skinned settlers who would arrive soon in the east. Their migration path would be symbolized by a series of smaller Turtle Islands, which was confirmed with "miigis" shells (i.e., cowry shells). After receiving assurance from their "Allied Brothers" (i.e., Mi'kmaq) and "Father" (i.e., Abenaki) of their safety to move inland, the Anishinaabeg gradually migrated west along the Saint Lawrence River to the Ottawa River to Lake Nipissing, and then to the Great Lakes.

The first of the smaller Turtle Islands was "Mooniyaa", where "Mooniyaang" (present-day Montreal) developed. The "second stopping place" was in the vicinity of the "Wayaanag-gakaabikaa" (Concave Waterfalls, i.e., Niagara Falls). At their "third stopping place", near the present-day city of Detroit, Michigan, the Anishinaabeg divided into six groups, of which the Ojibwe was one.

The first significant new Ojibwe culture-center was their "fourth stopping place" on "Manidoo Minising" (Manitoulin Island). Their first new political-center was referred to as their "fifth stopping place", in their present country at "Baawiting" (Sault Ste. Marie).

Continuing their westward expansion, the Ojibwe divided into the "northern branch", following the north shore of Lake Superior, and the "southern branch", along its south shore.

As the people continued to migrate westward, the "northern branch" divided into a "westerly group" and a "southerly group". The "southern branch" and the "southerly group" of the "northern branch" came together at their "sixth stopping place" on Spirit Island () located in the Saint Louis River estuary at the western end of Lake Superior. (This has since been developed as the present-day Duluth/Superior cities.) The people were directed in a vision by the "miigis" being to go to the "place where there is food (i.e., wild rice) upon the waters." Their second major settlement, referred to as their "seventh stopping place", was at Shaugawaumikong (or "Zhaagawaamikong", French, "Chequamegon") on the southern shore of Lake Superior, near the present La Pointe, Wisconsin.

The "westerly group" of the "northern branch" migrated along the Rainy River, Red River of the North, and across the northern Great Plains until reaching the Pacific Northwest. Along their migration to the west, they came across many "miigis", or cowry shells, as told in the prophecy.

The first historical mention of the Ojibwe occurs in the French Jesuit "Relation of 1640", a report by the missionary priests to their superiors in France. Through their friendship with the French traders ("coureurs des bois" and voyageurs), the Ojibwe gained guns, began to use European goods, and began to dominate their traditional enemies, the Lakota and Fox to their west and south. They drove the Sioux from the Upper Mississippi region to the area of the present-day Dakotas, and forced the Fox down from northern Wisconsin. The latter allied with the Sauk for protection.

By the end of the 18th century, the Ojibwe controlled nearly all of present-day Michigan, northern Wisconsin, and Minnesota, including most of the Red River area. They also controlled the entire northern shores of lakes Huron and Superior on the Canadian side and extending westward to the Turtle Mountains of North Dakota. In the latter area, the French Canadians called them Ojibwe or "Saulteaux".
The Ojibwe (Chippewa) were part of a long-term alliance with the Anishinaabe Ottawa and Potawatomi peoples, called the Council of Three Fires. They fought against the Iroquois Confederacy, based mainly to the southeast of the Great Lakes in present-day New York, and the Sioux to the west. The Ojibwa stopped the Iroquois advance into their territory near Lake Superior in 1662. Then they formed an alliance with other tribes such as the Huron and the Ottawa who had been displaced by the Iroquois invasion. Together they launched a massive counterattack against the Iroquois and drove them out of Michigan and Southern Ontario until they were forced to flee back to their original homeland in upstate New York. At the same time the Iroquois were subjected to attacks by the French. This was the beginning of the end of the Iroquois Confederacy as they were put on the defensive. The Ojibwe expanded eastward, taking over the lands along the eastern shores of Lake Huron and Georgian Bay.

In 1745, they adopted guns from the British in order to repel the Dakota people in the Lake Superior area, pushing them to the south and west. In the 1680s the Ojibwa defeated the Iroquois who dispersed their Huron allies and trading partners. This victory allowed them a "golden age" in which they ruled uncontested in southern Ontario.

Often, treaties known as "Peace and Friendship Treaties" were made to establish community bonds between the Ojibwe and the European settlers. These established the groundwork for cooperative resource-sharing between the Ojibwe and the settlers. The United States and Canada viewed later treaties offering land cessions as offering territorial advantages. The Ojibwe did not understand the land cession terms in the same way because of the cultural differences in understanding the uses of land. The governments of the US and Canada considered land a commodity of value that could be freely bought, owned and sold.

The Ojibwe believed it was a fully shared resource, along with air, water and sunlight—despite having an understanding of "territory". At the time of the treaty councils, they could not conceive of separate land sales or exclusive ownership of land. Consequently, today, in both Canada and the US, legal arguments in treaty-rights and treaty interpretations often bring to light the differences in cultural understanding of treaty terms to come to legal understanding of the treaty obligations.

In part due to its long trading alliance, the Ojibwe allied with the French against Great Britain and its colonists in the Seven Years' War (also called the French and Indian War). After losing the war in 1763, France was forced to cede its colonial claims to lands in Canada and east of the Mississippi River to Britain. After Pontiac's War and adjusting to British colonial rule, the Ojibwe allied with British forces and against the United States in the War of 1812. They had hoped that a British victory could protect them against United States settlers' encroachment on their territory.

Following the war, the United States government tried to forcibly remove all the Ojibwe to Minnesota, west of the Mississippi River. The Ojibwe resisted, and there were violent confrontations. In the Sandy Lake Tragedy, several hundred Ojibwe died because of the federal government's failure to deliver fall annuity payments. Through the efforts of Chief Buffalo and the rise of popular opinion in the US against Ojibwe removal, the bands east of the Mississippi were allowed to return to reservations on ceded territory. A few families were removed to Kansas as part of the Potawatomi removal.
In British North America, the Royal Proclamation of 1763 following the Seven Years' War governed the cession of land by treaty or purchase. Subsequently, France ceded most of the land in Upper Canada to Great Britain. Even with the Jay Treaty signed between Great Britain and the United States following the American Revolutionary War, the newly formed United States did not fully uphold the treaty. As it was still preoccupied by war with France, Great Britain ceded to the United States much of the lands in Ohio, Indiana, Michigan, parts of Illinois and Wisconsin, and northern Minnesota and North Dakota to settle the boundary of their holdings in Canada.

In 1807, the Ojibwe joined three other tribes, the Odawa, Potawatomi and Wyandot people, in signing the Treaty of Detroit. The agreement, between the tribes and William Hull, representing the Michigan Territory, gave the United States a portion of today's Southeastern Michigan and a section of Ohio near the Maumee River. The tribes were able to retain small pockets of land in the territory.

In Canada, many of the land cession treaties the British made with the Ojibwe provided for their rights for continued hunting, fishing and gathering of natural resources after land sales. The government signed numbered treaties in northwestern Ontario, Manitoba, Saskatchewan, and Alberta. British Columbia had not signed treaties until the late 20th century, and most areas have no treaties yet. The government and First Nations are continuing to negotiate treaty land entitlements and settlements. The treaties are constantly being reinterpreted by the courts because many of them are vague and difficult to apply in modern times. The numbered treaties were some of the most detailed treaties signed for their time. The Ojibwe Nation set the agenda and negotiated the first numbered treaties before they would allow safe passage of many more British settlers to the prairies.

Ojibwe communities have a strong history of political and social activism. Long before contact, they were closely aligned with Odawa and Potawatomi people in the Council of the Three Fires. From the 1870s to 1938, the Grand General Indian Council of Ontario attempted to reconcile multiple traditional models into one cohesive voice to exercise political influence over colonial legislation. In the West, 16 Plains Cree and Ojibwe bands formed the Allied Bands of Qu'Appelle in 1910 in order to redress concerns about the failure of the government to uphold Treaty 4’s promises.

During its Indian Removal of the 1830s, the US government attempted to relocate tribes from the east to the west of the Mississippi River as the white pioneers increasingly migrated west. By the late 19th century, the government policy was to move tribes onto reservations within their territories. The government attempted to do this to the "Anishinaabe" in the Keweenaw Peninsula in the Upper Peninsula of Michigan.

The Battle of the Brule was an October 1842 battle between the La Pointe Band of Ojibwe Indians and a war party of Dakota Indians. The battle took place along the Brule River (Bois Brule) in what is today northern Wisconsin and resulted in a decisive victory for the Ojibwe.

The Ojibwe live in groups (otherwise known as "bands"). Most Ojibwe, except for the Great Plains bands, lived a sedentary lifestyle, engaging in fishing and hunting to supplement the women's cultivation of numerous varieties of maize and squash, and the harvesting of "manoomin" (wild rice). Their typical dwelling was the "wiigiwaam" (wigwam), built either as a "waginogaan" (domed-lodge) or as a "nasawa'ogaan" (pointed-lodge), made of birch bark, juniper bark and willow saplings.
They developed a form of pictorial writing, used in religious rites of the "Midewiwin" and recorded on birch bark scrolls and possibly on rock. The many complex pictures on the sacred scrolls communicate much historical, geometrical, and mathematical knowledge. The use of petroforms, petroglyphs, and pictographs was common throughout the Ojibwe traditional territories. Petroforms and medicine wheels were a way to teach the important concepts of four directions and astronomical observations about the seasons, and to use as a memorizing tool for certain stories and beliefs.

Ceremonies also used the "miigis" shell (cowry shell), which is found naturally in distant coastal areas. Their use of such shells demonstrates there was a vast trade network across the continent at some time. The use and trade of copper across the continent has also been proof of a large trading network that took place for thousands of years, as far back as the Hopewell tradition. Certain types of rock used for spear and arrow heads were also traded over large distances.
During the summer months, the people attend "jiingotamog" for the spiritual and "niimi'idimaa" for a social gathering (pow-wows or "pau waus") at various reservations in the "Anishinaabe-Aki" (Anishinaabe Country). Many people still follow the traditional ways of harvesting wild rice, picking berries, hunting, making medicines, and making maple sugar. Many of the Ojibwe take part in sun dance ceremonies across the continent. The sacred scrolls are kept hidden away until those who are worthy and respect them are given permission to see and interpret them properly.

The Ojibwe would not bury their dead in a burial mound. Many erect a "jiibegamig" or a "spirit-house" over each mound. A traditional burial mound would typically have a wooden marker, inscribed with the deceased's "doodem" (clan sign). Because of the distinct features of these burials, Ojibwe graves have been often looted by grave robbers. In the United States, many Ojibwe communities safe-guard their burial mounds through the enforcement of the 1990 Native American Graves Protection and Repatriation Act.

As with various other North American peoples, the Ojibwe culture includes a third gender. Ojibwe Two-Spirit women take on men's roles, classified as either "Iron Woman" or "Half Sky". Generally, two-spirit men practiced Shamanism and it was taboo for women to take on this role, but a two-spirit following this path was called an Iron Woman. The Half Sky two-spirit would be physically good at a man's trade (like hunting). Also, there is an instance when a wife becomes a widow and takes on her husband's manly deeds; this woman is called a "Woman Covered All Over". (Landes 153, 176, 178-179, and Merriam- Webster Dictionary).

Several Ojibwe bands in the United States cooperate in the Great Lakes Indian Fish & Wildlife Commission, which manages the treaty hunting and fishing rights in the Lake Superior-Lake Michigan areas. The commission follows the directives of U.S. agencies to run several wilderness areas. Some Minnesota Ojibwe tribal councils cooperate in the 1854 Treaty Authority, which manages their treaty hunting and fishing rights in the Arrowhead Region. In Michigan, the Chippewa-Ottawa Resource Authority manages the hunting, fishing and gathering rights about Sault Ste. Marie, and the resources of the waters of lakes Michigan and Huron. In Canada, the Grand Council of Treaty No. 3 manages the Treaty 3 hunting and fishing rights related to the area around Lake of the Woods.

Traditionally, the Ojibwe had a patrilineal system, in which children were considered born to the father's clan. For this reason, children with French or English fathers were considered outside the clan and Ojibwe society unless adopted by an Ojibwe male. They were sometimes referred to as "white" because of their fathers, regardless if their mothers were Ojibwe, as they had no official place in the Ojibwe society. The people would shelter the woman and her children, but they did not have the same place in the culture as children born to Ojibwe fathers.

Ojibwe understanding of kinship is complex, and includes not only the immediate family but also the extended family. It is considered a modified bifurcate merging kinship system. As with any bifurcate-merging kinship system, siblings generally share the same kinship term with parallel cousins because they are all part of the same clan. The modified system allows for younger siblings to share the same kinship term with younger cross-cousins. Complexity wanes further from the speaker's immediate generation, but some complexity is retained with female relatives. For example, "ninooshenh" is "my mother's sister" or "my father's sister-in-law"—i.e., my parallel-aunt, but also "my parent's female cross-cousin". Great-grandparents and older generations, as well as great-grandchildren and younger generations, are collectively called "aanikoobijigan". This system of kinship reflects the Anishinaabe philosophy of interconnectedness and balance among all living generations, as well as of all generations of the past and of the future.

The Ojibwe people were divided into a number of "odoodeman" (clans; singular: "doodem") named primarily for animals and birds totems (pronounced "doodem"). The five original totems were "Wawaazisii" (Bullhead), "Baswenaazhi" ("Echo-maker", i.e., Crane), "Aan'aawenh" (Pintail Duck), "Nooke" ("Tender", i.e., Bear) and "Moozwaanowe" ("Little" Moose-tail). The Crane totem was the most vocal among the Ojibwe, and the Bear was the largest – so large, that it was sub-divided into body parts such as the head, the ribs and the feet. Each clan had certain responsibilities among the people. People had to marry a spouse from a different clan.

Traditionally, each band had a self-regulating council consisting of leaders of the communities' clans, or "odoodemaan". The band was often identified by the principal "doodem". In meeting others, the traditional greeting among the Ojibwe people is, "What is your 'doodem'?" (""Aaniin gidoodem?"" or ""Awanen gidoodem?"") The response allows the parties to establish social conduct by identifying as family, friends or enemies. Today, the greeting has been shortened to ""Aanii"". Pronounced; (Ah-nee)

The Ojibwe have a number of spiritual beliefs passed down by oral tradition under the Midewiwin teachings. These include a creation story and a recounting of the origins of ceremonies and rituals. Spiritual beliefs and rituals were very important to the Ojibwe because spirits guided them through life. Birch bark scrolls and petroforms were used to pass along knowledge and information, as well as for ceremonies. Pictographs were also used for ceremonies.

The sweatlodge is still used during important ceremonies about the four directions, when oral history is recounted. Teaching lodges are common today to teach the next generations about the language and ancient ways of the past. The traditional ways, ideas, and teachings are preserved and practiced in such living ceremonies.

The Ojibwe crafted the dreamcatcher. They believe that if one is hung above the head of a sleeper, it will catch and trap bad dreams, preventing them from reaching the dreamer. Traditional Ojibwe use dreamcatchers only for children, as they believe that adults should be able to interpret their dreams, good or bad, and use them in their lives.

Plants used by the Ojibwe include Agrimonia gryposepala, used for urinary problems, and "pinus strobus", the resin of which was used to treat infections and gangrene. The roots of Symphyotrichum novae-angliae are smoked in pipes to attract game. Allium tricoccum is eaten as part of Ojibwe cuisine. They also use a decoction as a quick-acting emetic. An infusion of the "alba" subspecies of Silene latifolia is used as physic. The South Ojibwa use a decoction of the root Viola canadensis for pains near the bladder. The Ojibwa are documented to use the root of Uvularia grandiflora for pain in the solar plexus, which may refer to pleurisy. They take a compound decoction of the root of Ribes glandulosum for back pain and for "female weakness." The Ojibwe eat the corms of Sagittaria cuneata for indigestion, and also as a food, eaten boiled fresh, dried or candied with maple sugar. Muskrat and beavers store them in large caches, which they have learned to recognize and appropriate. They take an infusion of the Antennaria howellii ssp. neodioica after childbirth to purge afterbirth and to heal.
They use the roots of Solidago rigida, using a decoction of root as an enema and take an infusion of the root for "stoppage of urine.

In his "History of the Ojibway People" (1855), William W. Warren recorded 10 major divisions of the Ojibwe in the United States. He mistakenly omitted the Ojibwe located in Michigan, western Minnesota and westward, and all of Canada. When identified major historical bands located in Michigan and Ontario are added, the count becomes 15:
These 15 major divisions developed into the following Ojibwe Bands and First Nations of today. Bands are listed under their respective tribes where possible. See also the listing of Saulteaux communities.


When was the first graphene production technique developed?

The theory of graphene was first explored by Wallace in 1947 as a starting point for understanding the electronic properties of 3D graphite. The emergent massless Dirac equation was first pointed out by Semenoff, DiVincenzo and Mele. The earliest TEM images of few-layer graphite were published by Ruess and Vogt in 1948. An early, detailed study on few-layer graphite dates to 1962 when Boehm and colleagues reported producing monolayer flakes of reduced graphene oxide. Efforts to make thin films of graphite by mechanical exfoliation started in 1990, but nothing thinner than 50 to 100 layers was produced before 2004. Initial attempts to make atomically thin graphitic films employed exfoliation techniques similar to the drawing method. Multilayer samples down to 10 nm in thickness were obtained.

Graphene

Graphene is an allotrope (form) of carbon consisting of a single layer of carbon atoms arranged in a hexagonal lattice. It is a semimetal with small overlap between the valence and the conduction bands (zero bandgap material). It is the basic structural element of many other allotropes of carbon, such as graphite, charcoal, carbon nanotubes and fullerenes.

Graphene has many uncommon properties. It is the strongest material ever tested, conducts heat and electricity efficiently, and is nearly transparent. Graphene shows a large and nonlinear diamagnetism, greater than that of graphite, and can be levitated by neodymium magnets.

Scientists theorized about graphene for years. It had been produced unintentionally in small quantities for centuries through the use of pencils and other similar graphite applications. It was observed originally in electron microscopes in 1962, but it was studied only while supported on metal surfaces. The material was later rediscovered, isolated, and characterized in 2004 by Andre Geim and Konstantin Novoselov at the University of Manchester. Research was informed by existing theoretical descriptions of its composition, structure, and properties. This work resulted in the two winning the Nobel Prize in Physics in 2010 "for groundbreaking experiments regarding the two-dimensional material graphene."

"Graphene" is a combination of "graphite" and the suffix -ene, named by Hanns-Peter Boehm and colleagues, who produced and observed single-layer carbon foils in 1962.

Boehm et al. introduced the term "graphene" in 1986 to describe single sheets of graphite. Graphene can be considered an "infinite alternant" (only six-member carbon ring) polycyclic aromatic hydrocarbon.

The International Union of Pure and Applied Chemistry (IUPAC) notes, "previously, descriptions such as graphite layers, carbon layers, or carbon sheets have been used for the term graphene...it is incorrect to use for a single layer a term which includes the term graphite, which would imply a three-dimensional structure. The term graphene should be used only when the reactions, structural relations or other properties of individual layers are discussed."

Geim defined "isolated or free-standing graphene" as "graphene is a single atomic plane of graphite, which – and this is essential – is sufficiently isolated from its environment to be considered free-standing." This definition is narrower than the IUPAC definition and refers to cloven, transferred and suspended graphene. Other forms such as graphene grown on various metals, can become free-standing if, for example, suspended or transferred to silicon dioxide () or silicon carbide.

Graphene is a crystalline allotrope of carbon with 2-dimensional properties. Its carbon atoms are packed densely in a regular atomic-scale chicken wire (hexagonal) pattern.

Each atom has four bonds: one σ bond with each of its three neighbors and one π-bond that is oriented out of plane. The atoms are about 1.42 Å apart.

Graphene's hexagonal lattice can be regarded as two interleaving triangular lattices. This perspective was successfully used to calculate the band structure for a single graphite layer using a tight-binding approximation.

Graphene's stability is due to its tightly packed carbon atoms and a sp orbital hybridization – a combination of orbitals s, p and p that constitute the σ-bond. The final p electron makes up the π-bond. The π-bonds hybridize together to form the π-band and π∗-bands. These bands are responsible for most of graphene's notable electronic properties, via the half-filled band that permits free-moving electrons.

Graphene sheets in solid form usually show evidence in diffraction for graphite's (002) layering. This is true of some single-walled nanostructures. However, unlayered graphene with only (hk0) rings has been found in the core of presolar graphite onions. TEM studies show faceting at defects in flat graphene sheets and suggest a role for two-dimensional crystallization from a melt.

Graphene can self-repair holes in its sheets when exposed to molecules containing carbon, such as hydrocarbons. Bombarded with pure carbon atoms, the atoms perfectly align into hexagons, completely filling the holes.

The atomic structure of isolated, single-layer graphene is studied by TEM on sheets of graphene suspended between bars of a metallic grid. Electron diffraction patterns showed the expected honeycomb lattice. Suspended graphene showed "rippling" of the flat sheet, with amplitude of about one nanometer. These ripples may be intrinsic to the material as a result of the instability of two-dimensional crystals, or may originate from the ubiquitous dirt seen in all TEM images of graphene. Atomic resolution real-space images of isolated, single-layer graphene on substrates are available via scanning tunneling microscopy (STM). Photoresist residue, which must be removed to obtain atomic-resolution images, may be the "adsorbates" observed in TEM images, and may explain the observed rippling. Rippling on is caused by conformation of graphene to the underlying and is not intrinsic.

Ab initio calculations show that a graphene sheet is thermodynamically unstable if its size is less than about ("graphene is the least stable structure until about 6000 atoms") and becomes the most stable fullerene (as within graphite) only for molecules larger than 24,000 atoms.

Analogs (also referred to as "artificial graphene") are two-dimensional systems that exhibit similar properties to graphene. Analogs can be systems in which the physics is easier to observe and to manipulate. In those systems, electrons are not always the chosen particles—they might be optical photons, microwave photons, plasmons, microcavity polaritons or even atoms. Also, the honeycomb structure in which those particles evolve can be of a different nature than carbon atoms in graphene. It can be, respectively, a photonic crystal, an array of metallic rods, metallic nanoparticles, a lattice of coupled microcavities or an optical lattice.

Graphene has a theoretical specific surface area (SSA) of. This is much larger than that reported to date for carbon black (typically smaller than ) or for carbon nanotubes (CNTs), from ≈100 to and is similar to activated carbon.

Graphene is a zero-gap semiconductor, because its conduction and valence bands meet at the Dirac points, which are six locations in momentum space, on the edge of the Brillouin zone, divided into two non-equivalent sets of three points. The two sets are labeled K and K'. The sets give graphene a valley degeneracy of. By contrast, for traditional semiconductors the primary point of interest is generally Γ, where momentum is zero. However, if the in-plane direction is confined, in which case it is referred to as a nanoribbon, its electronic structure is different. If it is "zig-zag", the bandgap is zero. If it is "armchair", the bandgap is non-zero (see figure)...

Graphene displays remarkable electron mobility at room temperature, with reported values in excess of. Hole and electron mobilities were expected to be nearly identical. The mobility is nearly independent of temperature between and, which implies that the dominant scattering mechanism is defect scattering. Scattering by graphene's acoustic phonons intrinsically limits room temperature mobility to at a carrier density of, times greater than copper.

The corresponding resistivity of graphene sheets would be. This is less than the resistivity of silver, the lowest otherwise known at room temperature. However, on substrates, scattering of electrons by optical phonons of the substrate is a larger effect than scattering by graphene’s own phonons. This limits mobility to. Charge transport is affected by adsorption of contaminants such as water and oxygen molecules. This leads to non-repetitive and large hysteresis I-V characteristics.

Electrons propagating through graphene's honeycomb lattice effectively lose their mass, producing quasi-particles (known as massless Dirac fermions) that are described by a 2D analogue of the Dirac equation rather than the Schrödinger equation for spin- particles.

Superconductivity has been observed in twisted bilayer graphene.

Graphene's unique optical properties produce an unexpectedly high opacity for an atomic monolayer in vacuum, absorbing of red light, where "α" is the fine-structure constant. This is a consequence of the "unusual low-energy electronic structure of monolayer graphene that features electron and hole conical bands meeting each other at the Dirac point... [which] is qualitatively different from more common quadratic massive bands." Based on the Slonczewski–Weiss–McClure (SWMcC) band model of graphite, the interatomic distance, hopping value and frequency cancel when optical conductance is calculated using Fresnel equations in the thin-film limit.

Although confirmed experimentally, the measurement is not precise enough to improve on other techniques for determining the fine-structure constant.

Multi-parametric surface plasmon resonance was used to characterize both thickness and refractive index of chemical-vapor-deposition (CVD)-grown graphene films. The measured refractive index and extinction coefficient values at 670 nm wavelength are 3.135 and 0.897, respectively. The thickness was determined as 3.7 Å from a 0.5 mm area, which agrees with 3.35 Å reported for layer-to-layer carbon atom distance of graphite crystals.

The method can be used for real-time label-free interactions of graphene with organic and inorganic substances. The existence of unidirectional surface plasmons in the nonreciprocal graphene-based gyrotropic interfaces has been demonstrated theoretically. By efficiently controlling the chemical potential of graphene, the unidirectional working frequency can be continuously tunable from THz to near-infrared and even visible. Particularly, the unidirectional frequency bandwidth can be 1–2 orders of magnitude larger than that in metal under the same magnetic field, which arises from the superiority of extremely small effective electron mass in graphene.

Graphene's band gap can be tuned from 0 to (about 5 micrometre wavelength) by applying voltage to a dual-gate bilayer graphene field-effect transistor (FET) at room temperature. The optical response of graphene nanoribbons is tunable into the terahertz regime by an applied magnetic field. Graphene/graphene oxide systems exhibit electrochromic behavior, allowing tuning of both linear and ultrafast optical properties.

A graphene-based Bragg grating (one-dimensional photonic crystal) demonstrated its capability for excitation of surface electromagnetic waves in the periodic structure using a He–Ne laser as the light source.

Such unique absorption could become saturated when the input optical intensity is above a threshold value. This nonlinear optical behavior is termed saturable absorption and the threshold value is called the saturation fluence. Graphene can be saturated readily under strong excitation over the visible to near-infrared region, due to the universal optical absorption and zero band gap. This has relevance for the mode locking of fiber lasers, where fullband mode locking has been achieved by a graphene-based saturable absorber. Due to this special property, graphene has wide application in ultrafast photonics. The optical response of graphene/graphene oxide layers can be tuned electrically. Saturable absorption in graphene could occur at the Microwave and Terahertz bands, owing to its wideband optical absorption property. The microwave saturable absorption in graphene demonstrates the possibility of graphene microwave and terahertz photonics devices, such as a microwave saturable absorber, modulator, polarizer, microwave signal processing and broad-band wireless access networks.

Under more intensive laser illumination, graphene could possess a nonlinear phase shift due to the optical nonlinear Kerr effect. Based on a typical open and close aperture z-scan measurement, graphene possesses a nonlinear Kerr coefficient of, almost nine orders of magnitude larger than that of bulk dielectrics. This suggests that graphene may be a powerful nonlinear Kerr medium, with the possibility of observing a variety of nonlinear effects, the most important of which is the soliton. A 2016 study has shown that the nonlinear refractive index of graphene is negative. Thermal lens spectroscopy can be used for measuring the thermo-optic coefficient of graphene and inspecting its thermal nonlinearity.

Several techniques can prepare nanostructured graphene, e.g., graphene quantum dots (GQDs); these techniques mainly include electron beam lithography, chemical synthesis, electrochemical preparation, graphene oxide (GO) reduction, C60 catalytic transformation, the microwave assisted hydrothermal method (MAH), the Soft-Template method, the hydrothermal method, and the ultrasonic exfoliation method.

Thermal transport in graphene is an active area of research which has attracted attention because of the potential for thermal management applications. Early measurements of the thermal conductivity of suspended graphene reported an exceptionally large thermal conductivity of approximately, compared with the thermal conductivity of pyrolytic graphite of approximately at room temperature. However, later studies have questioned whether this ultrahigh value was overestimated, and instead measured thermal conductivities between – for suspended single layer graphene. The large range can be attributed to large measurement uncertainties as well as variations in the graphene quality and processing conditions. In addition, when single-layer graphene is supported on an amorphous material, the thermal conductivity is reduced to about – at room temperature as a result of scattering of graphene lattice waves by the substrate, and can be even lower for few layer graphene encased in amorphous oxide. Likewise, polymeric residue can contribute to a similar decrease for suspended graphene to approximately –for bilayer graphene.

It has been suggested that the isotopic composition, the ratio of C to C, has a significant impact on thermal conductivity. For example, isotopically pure C graphene has higher thermal conductivity than either a 50:50 isotope ratio or the naturally occurring 99:1 ratio. It can be shown by using the Wiedemann–Franz law, that the thermal conduction is phonon-dominated. However, for a gated graphene strip, an applied gate bias causing a Fermi energy shift much larger than "k""T" can cause the electronic contribution to increase and dominate over the phonon contribution at low temperatures. The ballistic thermal conductance of graphene is isotropic.

Potential for this high conductivity can be seen by considering graphite, a 3D version of graphene that has basal plane thermal conductivity of over (comparable to diamond). In graphite, the c-axis (out of plane) thermal conductivity is over a factor of ≈100 smaller due to the weak binding forces between basal planes as well as the larger lattice spacing. In addition, the ballistic thermal conductance of graphene gives the lower limit of the ballistic thermal conductances, per unit circumference and length of carbon nanotubes.

Despite its 2-D nature, graphene has 3 acoustic phonon modes. The two in-plane modes (LA, TA) have a linear dispersion relation, while the out of plane mode (ZA) has a quadratic dispersion relation. Due to this, the "T" dependent thermal conductivity contribution of the linear modes is dominated at low temperatures by the T contribution of the out-of-plane mode. Some graphene phonon bands display negative Grüneisen parameters (GPs). At low temperatures (where most optical modes with positive GPs are still not excited) the contribution from the negative GPs will be dominant and thermal expansion coefficient (which is directly proportional to GPs) negative. The lowest negative GPs correspond to the lowest transverse acoustic ZA modes. Phonon frequencies for such modes increase with the in-plane lattice parameter since atoms in the layer upon stretching will be less free to move in the z direction. This is similar to the behavior of a stretched string that has vibrations of smaller amplitude and higher frequency. This phenomenon, named "membrane effect", was predicted by Lifshitz in 1952.

A prediction that was published in 2015 suggested a melting point of ≈4125 K. Recent and more sophisticated modelling has increased this temperature to at least 5000 K. At 6000 K (the sun's surface having an effective temperature of 5,777 K) graphene melts into an agglomeration of loosely coupled doubled bonded chains, before becoming a gas.

The carbon–carbon bond length in graphene is about 0.142 nanometers. Graphene sheets stack to form graphite with an interplanar spacing of.

Graphene is the strongest material ever tested, with an intrinsic tensile strength of 130.5 GPa and a Young's modulus of (). The Nobel announcement gave the strength as 42 N/m; the mass of 1 m as, and the electrical resistance of a square as 31 Ω.

Large-angle-bent graphene monolayer has been achieved with negligible strain, showing mechanical robustness of the two-dimensional carbon nanostructure. Even with extreme deformation, excellent carrier mobility in monolayer graphene can be preserved.

The spring constant of suspended graphene sheets has been measured using an atomic force microscope (AFM). Graphene sheets were suspended over cavities where an atomic force microscope (AFM) tip was used to apply a stress to the sheet to test its mechanical properties. Its spring constant was in the range 1–5 N/m and the stiffness was, which differs from that of bulk graphite. These intrinsic properties could lead to applications such as NEMS as pressure sensors and resonators. Due to its large surface energy and out of plane ductility, flat graphene sheets are unstable with respect to scrolling, i.e. bending into a cylindrical shape, which is its lower-energy state.

As is true of all materials, regions of graphene are subject to thermal and quantum fluctuations in relative displacement. Although the amplitude of these fluctuations is bounded in 3D structures (even in the limit of infinite size), the Mermin–Wagner theorem shows that the amplitude of long-wavelength fluctuations grows logarithmically with the scale of a 2D structure and would therefore be unbounded in structures of infinite size. Local deformation and elastic strain are negligibly affected by this long-range divergence in relative displacement. It is believed that a sufficiently large 2D structure, in the absence of applied lateral tension, will bend and crumple to form a fluctuating 3D structure. Ripples have been observed in suspended layers of graphene. It has been proposed that the ripples are caused by thermal fluctuations in the material. As a consequence of these dynamical deformations, it is debatable whether graphene is truly a 2D structure. In 2014 it was shown that these ripples, if amplified through the introduction of vacancy defects, can impart a negative Poisson's ratio into graphene, resulting in the thinnest auxetic material known.

Graphene nanosheets can be incorporated into a nickel matrix through a plating process to form Ni-graphene composites on a target substrate. The enhancement in mechanical properties of the composites is attributed to the high interaction between Ni and graphene and the prevention of the dislocation sliding in the Ni matrix by the graphene.

Despite its strength, graphene is also relatively brittle, with a fracture toughness of about 4 MPa. This indicates that imperfect graphene is likely to crack in a brittle manner like ceramic materials, as opposed to many metallic materials that have fracture toughnesses in the range of 15–50 MPa. Graphene shows a greater ability to distribute force from an impact than any known material, ten times that of steel per unit weight. The force was transmitted at.

In 2011 graphene was shown to accelerate the osteogenic differentiation of human mesenchymal stem cells without the use of biochemical inducers.

In 2015 graphene was used to create biosensors with epitaxial graphene on silicon carbide. The sensors bind to 8-hydroxydeoxyguanosine (8-OHdG) and is capable of selective binding with antibodies. The presence of 8-OHdG in blood, urine and saliva is commonly associated with DNA damage. Elevated levels of 8-OHdG have been linked to increased risk of several cancers. A commercial version of a graphene biosensor has been used as a protein binding sensor platform.

In 2016 uncoated graphene was shown to serve as a neuro-interface electrode without altering or damaging properties such as signal strength or formation of scar tissue. Graphene electrodes in the body stay significantly more stable than electrodes of tungsten or silicon because of properties such as flexibility, bio-compatibility and conductivity.

A production unit produces continuous monolayer sheets of High Strength Metallurgical Graphene (HSMG). The process is based on graphene growth on a liquid metal matrix.

Bilayer graphene displays the anomalous quantum Hall effect, a tunable band gap and potential for excitonic condensation. Bilayer graphene typically can be found either in twisted configurations where the two layers are rotated relative to each other or graphitic Bernal stacked configurations where half the atoms in one layer lie atop half the atoms in the other. Stacking order and orientation govern its optical and electronic properties. One synthesis method is chemical vapor deposition, which can produce large bilayer regions that almost exclusively conform to a Bernal stack geometry. Superconductivity has been observed in twisted bilayer graphene.

Graphene nanoribbons ("nanostripes" in the "zig-zag" orientation), at low temperatures, show spin-polarized metallic edge currents, which suggest spintronics applications. (In the "armchair" orientation, the edges behave like semiconductors.)

In 2013, a three-dimensional honeycomb of hexagonally arranged carbon was termed 3D graphene. Self-supporting 3D graphene was produced that year. Three dimensional bilayer graphene was reported in 2012 and 2014.

In 2016, a box-shaped graphene (BSG) nanostructure resulted from mechanical cleavage of pyrolytic graphite has been reported. The discovered nanostructure is a multilayer system of parallel hollow nanochannels located along the surface that displayed quadrangular cross-section. The thickness of the channel walls is approximately equal to 1 nm, the typical width of channel facets makes about 25 nm.

In 2017, freestanding graphene gyroids with 35 nm and 60 nm unit cells were fabricated via controlled direct chemical vapor deposition. They represent the smallest free standing periodic graphene 3D structures yet produced with a pore size of tens of nm. A graphene gyroid has five percent of the density of steel, yet is ten times as strong with an enormous surface area to volume ratio. An aerogel made of graphene layers separated by carbon nanotubes was measured at 0.16 milligrams per cubic centimeter. The material has superior elasticity and absorption: it can recover completely after more than 90% compression, and absorb up to 900 times its weight in oil, at a rate of 68.8 grams per second.

Multiple production techniques have been developed. Isolated 2D crystals cannot be grown via chemical synthesis beyond small sizes even in principle, because the rapid growth of phonon density with increasing lateral size forces 2D crystallites to bend into the third dimension. In all cases, graphene must bond to a substrate to retain its two-dimensional shape.

As of 2014, exfoliation produced graphene with the lowest number of defects and highest electron mobility. Geim and Novoselov initially used adhesive tape to pull graphene sheets away from graphite. Achieving single layers typically requires multiple exfoliation steps. After exfoliation the flakes are deposited on a silicon wafer. Alternatively a sharp single-crystal diamond wedge cleave layers from a graphite source. Another method is reduction of graphite oxide monolayer films, e.g. by hydrazine with annealing in argon/hydrogen with an almost intact carbon framework that allows efficient removal of functional groups. Measured charge carrier mobility exceeded /Vs. Defect-free, unoxidized graphene-containing liquids can be made from graphite using mixers that produce local shear rates greater than. Burning a graphite oxide coated DVD produced a conductive graphene film (1738 siemens per meter) and specific surface area (1520 square meters per gram) that was highly resistant and malleable.

Dispersing graphite in a liquid medium can produce graphene by sonication followed by centrifugation. The addition of dispersants ("e.g.", graphene quantum dots) can facilitate the exfoliation process, forming aqueous graphene dispersion with high yield. Such process is straightforward, low-cost, and environmentally friendly. Sonicating graphite at the interface of two immiscible liquids, most notably heptane and water, produced macro-scale graphene films. Graphite particles can be corroded in molten salts to form a variety of carbon nanostructures including graphene. Electrochemical synthesis can exfoliate graphene. Varying a pulsed voltage controls thickness, flake area, number of defects and affects its properties. The process begins by bathing the graphite in a solvent for intercalation. The process can be tracked by monitoring the solution’s transparency with an LED and photodiode.

Graphene has been prepared by using a sugar (e.g. glucose, sugar, fructose, etc.) This substrate-free "bottom-up" synthesis is safer, simpler and more environmentally friendly than exfoliation. The method can control thickness, ranging from monolayer to multilayers, which is known as "Tang-Lau Method".

Epitaxial graphene may be coupled to surfaces weakly enough (by Van der Waals forces) to retain the two dimensional electronic band structure of isolated graphene. Heating silicon carbide (SiC) to high temperatures () under low pressures (c. 10 torr) reduces it to graphene. A normal silicon wafer coated with a layer of germanium (Ge) dipped in dilute hydrofluoric acid strips the naturally forming germanium oxide groups, creating hydrogen-terminated germanium. CVD can coat that with graphene. A two-step CVD process is shown to grow graphene directly on TiO crystals or exfoliated TiO nanosheets without using a metal catalyst. The atomic structure of metal substrates including ruthenium, iridium, nickel and copper has been used as substrates for graphene production. Commercial copper foils have been used for graphene production, reducing substrate costs by 100-fold. Gaseous catalyst-assisted CVD paves the way for synthesizing high-quality graphene for device applications while avoiding the transfer process. Gram quantities were produced by the reduction of ethanol by sodium metal, followed by pyrolysis and washing with water. Growing graphene in an industrial resistive-heating cold wall CVD system was claimed to produce graphene 100 times faster than conventional CVD systems, cut costs by 99% and produce material with enhanced electronic qualities. Experiments with precise control of process parameters during cold wall CVD provided conclusive insight into the classical surface-mediated two dimensional nucleation and growth mechanism of graphene grown using catalytic CVD under conditions sought out in the semiconductor industry.

In applications where the thickness and packing density of the graphene layer need to be carefully controlled, the Langmuir-Blodgett method has been used to produce single layer films of graphene and graphene oxide which can then be reduced to graphene. Some of the benefits of Langmuir-Blodgett deposition include accurate control over the layered architecture of the graphene, that the layer-by-layer deposition process allows assembling any combination of thin carbon layers on a substrates, and that the assembly process is performed at room temperature and produces greater throughputs while being amenable to automation and mass production.

Graphene is the only form of carbon (or solid material) in which every atom is available for chemical reaction from two sides (due to the 2D structure). Atoms at the edges of a graphene sheet have special chemical reactivity. Graphene has the highest ratio of edge atoms of any allotrope. Defects within a sheet increase its chemical reactivity. The onset temperature of reaction between the basal plane of single-layer graphene and oxygen gas is below. Graphene combusts at. Graphene is commonly modified with oxygen- and nitrogen-containing functional groups and analyzed by infrared spectroscopy and X-ray photoelectron spectroscopy. However, determination of structures of graphene with oxygen- and nitrogen- functional groups requires the structures to be well controlled.

Contrary to the ideal 2D structure of graphene, chemical applications of graphene need either structural or chemical irregularities, as perfectly flat graphene is chemically inert. In other words, the definition of an ideal graphene is different in chemistry and physics.

Graphene placed on a soda-lime glass (SLG) substrate under ambient conditions exhibited spontaneous n-doping (1.33 × 10 "e"/cm) via surface-transfer. On p-type copper indium gallium diselenide (CIGS) semiconductor itself deposited on SLG n-doping reached 2.11 × 10 "e"/cm.

Various graphene derivatives, e.g., cyanographene and graphene acid, can be prepared via elegant chemistry of fluorographene. Cyanographene and graphene acid have high degree of functionalization (~15%), open band gap and are hydrophilic providing stable colloids in water.

Graphene is a transparent and flexible conductor that holds promise for various material/device applications, including solar cells, light-emitting diodes (LED), touch panels and smart windows or phones. Graphene has also been used in other fundamental electronic devices, such as capacitors and Field Effect Transistors (FETs), in which it can act as an atomically thin channel. In the same framework, fluorine-doped graphene has shown to have insulating properties and it can be used as a passivation layer in graphene FETs, leading to a substantial increase in carrier mobility.

Other early commercial uses of graphene include fillers such as a graphene-infused printer powder.

Graphene supercapacitors serve as energy storage alternative to traditional electrolytic batteries. Among advantages are fast charging, long life span and environmentally friendly production. Graphene supercapacitors produced by Skeleton Technologies have been commercially available since around 2015 and were first used in some specialized applications instead of traditional batteries. By 2017, commercial graphene supercapacitor units were available for industrial power applications, with maximal power output of 1500 kW. In 2016, Adgero announced a regenerative braking system (KERS) for large trucks that employed a graphene-based supercapacitor.

A joint effort from the University of Pennsylvania, Shanghai Institute of Ceramics, Queensland University of Technology, and Rice University has led to the development of carbon nanotube supercapacitors that can offer three times the energy density of most carbon-based nanomaterials. The scientists on this team utilized silicon and graphene to develop carbon nanotubes 4-6 nm wide and then doped the carbon atoms with nitrogen.
This process causes a chemical reaction which allows the material to store up to three times more energy without compromising their power density. Fuqiang Huang, a researcher on this project, reports that the fabricated carbon nanotube integrated supercapacitors are able to store up to 41 Wh/kg of energy; for comparison, an average lead acid battery has an energy density of 33 - 42 Wh/kg. Additionally, the supercapacitors offer a substantially higher power density of 70 - 250 Wh/kg compared to average lead acid battery which is capable of.2 - 1 Wh/kg. This breakthrough demonstrates that supercapacitors can provide a performance that matches, and even supersedes, of conventional energy storage methods. To put this achievement into perspective, a materials scientist from University of Pennsylvania, I-Wei Chen, stated that the implementation of these supercapacitors would allow an average bus to make 25 km trips with a recharge time of only 30 seconds.

In 2016, Henrik Fisker announced development of an electric car that will use graphene supercapacitor instead of lithium-ion batteries. Its low energy density as compared to lithium-ion batteries is being addressed. The planned electric car would target a minimum range of 400 miles (640 km). It has been announced later that the electric car produced by Fisker Inc. will still use lithium-ion batteries, but research in graphene supercapacitors will continue by Nanotech Energy Inc.

BAC's 2016 Mono model is said to be made out of graphene as a first of both a street-legal track car and a production car.
The first company to use graphene-made structural parts on a production model was Spania GTA, which unveiled a version of its Spano supercar fitted with graphene in 2015.

The global market for graphene reached $9 million by 2012 with most sales in the semiconductor, electronics, battery, energy storage or conversion, and composites industries.

The toxicity of graphene has been extensively debated. A review on graphene toxicity summarized the "in vitro", "in vivo", antimicrobial and environmental effects and highlights the various mechanisms of graphene toxicity. Nanotubes of graphene could reproduce the effects of asbestosis. The toxicity of graphene depends on its shape, size, purity, post-production processing steps, oxidative state, functional groups, dispersion state, synthesis methods, route, dose of administration, and exposure times.

Graphene nanoribbons, graphene nanoplatelets, and graphene nano–onions are non-toxic at concentrations up to 50 µg/ml. These nanoparticles do not alter the differentiation of human bone marrow stem cells towards osteoblasts (bone) or adipocytes (fat) suggesting that at low doses graphene nanoparticles are safe for biomedical applications. 10 µm few-layered graphene flakes were able to pierce cell membranes in solution. They were observed to enter initially via sharp and jagged points, allowing graphene to enter the cell. The physiological effects of this remain uncertain, and this remains a relatively unexplored field.

One of the first patents pertaining to the production of graphene was filed in October 2002 and granted in 2006. Two years later, in 2004 Geim and Novoselov extracted single-atom-thick crystallites from bulk graphite and transferred them onto thin silicon dioxide () on a silicon wafer, which electrically isolated the graphene. The cleavage technique led directly to the first observation of the anomalous quantum Hall effect in graphene, which provided direct evidence of graphene's theoretically predicted Berry's phase of massless Dirac fermions. The effect was reported by Geim's group and by Kim and Zhang, whose papers appeared in "Nature" in 2005. Geim and Novoselov received awards for their pioneering research on graphene, notably the 2010 Nobel Prize in Physics.

In 2013, the European Commission funded the large-scale research project Graphene Flagship with a total budget of €1 billion, involving 150 partner organizations.

Commercialization of graphene proceeded rapidly once commercial scale production was demonstrated. By 2017, 13 years after creation of the first laboratory graphene electronic device, an integrated graphene electronics chip was produced commercially and marketed to pharmaceutical researchers by Nanomedical Diagnostics in San Diego.