What is a sensor?

A sensor is a device that detects events that occur in the physical environment (like light, heat, motion, moisture, pressure, and more), and responds with an output, usually an electrical, mechanical or optical signal. The household mercury thermometer is a simple example of a sensor - it detects temperature and reacts with a measurable expansion of liquid. Sensors are everywhere - they can be found in everyday applications like touch-sensitive elevator buttons and lamp dimmer surfaces that respond to touch, but there are also many kinds of sensors that go unnoticed by most - like sensors that are used in medicine, robotics, aerospace and more.

Traditional kinds of sensors include temperature, pressure (thermistors, thermocouples, and more), moisture, flow (electromagnetic, positional displacement and more), movement and proximity (capacitive, photoelectric, ultrasonic and more), though innumerable other versions exist. sensors are divided into two groups: active and passive sensors. Active sensors (such as photoconductive cells or light detection sensors) require a power supply while passive ones (radiometers, film photography) do not.

Where can sensors be found?

Sensors are used in numerous applications, and can roughly be arranged in groups by forms of use:

  • Accelerometers: Micro Electro Mechanical technology based sensors, used mainly in mobile devices, medicine for patient monitoring (like pacemakers) and vehicular systems.
  • Biosensors: electrochemical technology based sensors, used for food and water testing, medical devices, fitness tracker and wristbands (that measure, for example, blood oxygen levels and heart rate) and military uses (biological warfare and more).
  • Image sensors: CMOS (Complementary Metal-Oxide Semiconductor) based sensors, used in consumer electronics, biometrics, traffic and security surveillance and PC imaging.
  • Motion Detectors: sensors which can be Infrared, Ultrasonic or Microwave/Radar technology. They are used in video games, security detection and light activation.

What is graphene?

Graphene is a two-dimensional material made of carbon atoms, often dubbed “miracle material” for its outstanding characteristics. It is 200 times stronger than steel at one atom thick, as well as the world’s most conductive material. It is so dense that the smallest atom of Helium cannot pass through it, but is also lightweight and transparent. Since its isolation in 2004, researchers and companies alike are fervently studying graphene, which is set to revolutionize various markets and produce improved processes, better performing components and new products.

Graphene and sensors

Graphene and sensors are a natural combination, as graphene’s large surface-to-volume ratio, unique optical properties, excellent electrical conductivity, high carrier mobility and density, high thermal conductivity and many other attributes can be greatly beneficial for sensor functions. The large surface area of graphene is able to enhance the surface loading of desired biomolecules, and excellent conductivity and small band gap can be beneficial for conducting electrons between biomolecules and the electrode surface.

Graphene-based chemical sensor photo

Graphene is thought to become especially widespread in biosensors and diagnostics. The large surface area of graphene can enhance the surface loading of desired biomolecules, and excellent conductivity and small band gap can be beneficial for conducting electrons between biomolecules and the electrode surface. Biosensors can be used, among other things, for the detection of a range of analytes like glucose, glutamate, cholesterol, hemoglobin and more. Graphene also has significant potential for enabling the development of electrochemical biosensors, based on direct electron transfer between the enzyme and the electrode surface.

Graphene will enable sensors that are smaller and lighter - providing endless design possibilities. They will also be more sensitive and able to detect smaller changes in matter, work more quickly and eventually even be less expensive than traditional sensors. Some graphene-based sensor designs contain a Field Effect Transistor (FET) with a graphene channel. Upon detection of the targeted analyte’s binding, the current through the transistor changes, which sends a signal that can be analyzed to determine several variables.

Graphene-based nanoelectronic devices have also been researched for use in DNA sensors (for detecting nucleobases and nucleotides), Gas sensors (for detection of different gases), PH sensors, environmental contamination sensors, strain and pressure sensors, and more.

Commercial activities in the field of graphene sensors

In June 2015, A collaboration between Bosch, the Germany-based engineering giant, and scientists at the Max-Planck Institute for Solid State Research yielded a graphene-based magnetic sensor 100 times more sensitive than an equivalent device based on silicon.

In August 2014, the US based Graphene Frontier announced raising $1.6m to expand the development and manufacturing of their graphene functionalized GFET sensors. Their “six sensors” brand for highly sensitive chemical and biological sensors can be used to diagnose diseases with sensitivity and efficiency unparalleled by traditional sensors.

Graphene Frontiers G-FET sensorG-FET Six-Sensors

In September 2014, the German AMO developed a graphene-based photodetector in collaboration with Alcatel Lucent Bell Labs, which is said to be the world’s fastest photodetector.

In November 2013, Nokia’s Cambridge research center developed a humidity sensor based on graphene oxide which is incredibly fast, thin, transparent, flexible and has great response and recovery times. Nokia also filed for a patent in August 2012 for a graphene-based photodetector that is transparent, thin and should ultimately be cheaper than traditional photodetectors.

Further reading

Latest Graphene Sensors news

Graphene-based sensors show great potential for environmental monitoring of NO2

Researchers at NPL, University of Surrey, University of London, Chalmers University and Linköping University have demonstrated proof-of-concept graphene-based sensors for environmental monitoring of ultra-low concentration NO2 in complex environments.

Graphene NO2 sensors image

The team reports that robust detection in a wide range of NO2 concentrations, 10-154 ppb, was achieved, highlighting the great potential for graphene-based NO2 sensors, with applications in environmental pollution monitoring, portable monitors, automotive and mobile sensors for a global real-time monitoring network.

MIT researchers create synthetic cells through controlled fracturing of graphene

MIT engineers recently managed to create cell-sized robots that could collect data about their environment, but were quite tricky to manufacture. Now, the team has found a way to mass produce these synthetic cells (syncells) through controlled fracturing of graphene.

MIT creates synthetic cells through controlled fracturing of graphene image

The previously developed MIT robots were so small, that there was no point trying to steer them, but they could still sense and observe, scanning their surroundings and storing data for long periods of time. Later, they could be filtered out and analyzed to get a reading of water quality, for example, or biomarkers for disease in a patient's bloodstream.

The Graphene Catalog - find your graphene material here

Impressions from the 2018 Graphene Week in San Sebastian

The Graphene-Info team attended this year's Graphene Week, organized by the Graphene Flagship in San Sebastian, Spain, 10-14 September 2018. The event attracted over 600 visitors from all over the world, and was extremely well organized.

While the talks and lectures were clearly scientifically-oriented, the commercial angle was also evident and many institutes and companies were there to show their recent product advancements. The Graphene Flagship's booth held a fascinating array of exhibits: graphene-enhanced retina and neural prosthesis (biomedical devices) by the ICN2 as a part of Braincom, Airbus' graphene composite for the leading edge of the tail of the Airbus A350, Nokia, Ericsson and AMO's graphene-based modulators and photodetectors for optical communications, a prosthetic robotic hand enhanced with graphene nerve sensors by the IIT, University of Cambridge's insole graphene-based pressure sensor and more.

Paragraf opens new R&D facility in Cambridge

Paragraf logo imageParagraf, the UK-based graphene technology development company, has announced the opening of an R&D facility in Cambridge. This follows the May 2018 announcement regarding seed investment of £2.9 million. The new site represents a turning point for graphene-based technologies, according to Paragraf, which it hopes will drive large-scale development of mass-market, graphene-based electronic devices.

Paragraf says its proprietary production technique overcomes the quality, contamination and reproducibility barriers faced by other graphene production methods. The customized equipment at the Cambridge facility will also allow Paragraf to convert its laboratory research into novel products, including next generation sensors, solid state electronics and energy storage cells.

Archer Exploration to work on graphene-based biosensors with undisclosed German biotech partner

Archer Exploration logo imageArcher Exploration has announced that it has entered into a legally binding Material Transfer Agreement (“MTA”) with a leading German biotechnology company, regarding Archer’s graphene-based biosensor development activities with The University of Adelaide ARC Graphene Hub.

The Agreement involves the transfer of materials between Archer and the Partner for use in the development of electrochemical biosensors for the semi-quantitative detection of disease state markers. The materials to be used include those held in the inventory of the Partner (e.g. infectious disease antigens, antibodies, disease state sera, coupling and assay reagents) and materials in the inventory of Archer’s wholly owned subsidiary Carbon Allotropes (e.g. graphene, ink formulations, and printed graphene electrodes).

XFNANO: Graphene and graphene-like materials since 2009 XFNANO: Graphene and graphene-like materials since 2009