Article last updated on: Jan 25, 2019

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.

The latest graphene sensor news:

Emberion raises €6 million to further its infrared imaging business

Emberion recently raised €6 million in funding to further develop their infrared imaging business. Currently, Emberion is one of the leaders in the development of these technologies, enabled by graphene and other layered materials.

Graphene Flagship partner Emberion develops high-performance SWIR sensors for imaging technologies. These devices detect light in both the visible and short-wave infrared (SWIR) wavelengths, enabling new applications in machine vision – used in surveillance, autonomous driving, food processing, waste sorting, and more. Emberion also leads Graphene Flagship Spearhead Project GBIRCAM, to design cheaper and more efficient broadband infrared devices.

New graphene-based neural probes improve detection of epileptic brain signals

Researchers the UK and Spain have demonstrated that tiny graphene neural probes can be used safely to improve our understanding of the causes of epilepsy.

The graphene depth neural probe (gDNP) consists of a millimeter-long linear array of micro-transistors imbedded in a micrometer-thin polymeric flexible substrate. The transistors were developed by a collaboration between The University of Manchester’s Neuromedicine Lab and UCL’s Institute of Neurology along with their Graphene Flagship partners.

Researchers develop graphene-biosensors for brain machine interfaces

Researchers at the University of Technology Sydney (UTS) have developed a novel graphene-based biosensor, set to drive new innovations in brain-controlled robotics.

The biosensor adheres to the skin of the face and head in order to detect electrical signals being sent by the brain. These signals can be translated into commands to control autonomous robotic systems. The sensor, made of epitaxial graphene grown onto a silicon carbide on silicon substrate, overcomes the major challenges of corrosion, durability and skin-contact resistance.

Researchers examine the mechanism of electric field detection in microscale graphene sensors

Researchers at Japan Advanced Institute of Science and Technology (JAIST) and Otowa Electric, a lightning protection equipment manufacturer, have used graphene as an electric field sensor that can detect both positive and negative electric fields.

Revisiting the Mechanism of Electric Field Sensing in Graphene Devices image

The response of the sensor is recorded as the change in drain current under the application of an electric field. In addition, by systematic analysis, The team established the mechanism of the graphene electric field sensor, which was found to be different from what they expected.

FLAG-ERA announces funding for 10 new projects on graphene research and applications

FLAG-ERA has announced the funding of 10 new projects on graphene and related materials, which will become partnering projects of the Graphene Flagship. The projects split between basic and applied research and innovation, covering areas from magnetic memories and photodetectors to novel batteries and neural inter-faces.

The FLAG-ERA initiative establishes links between the EU-funded FET Flagship projects and national and regional funding agencies in Member States. Through different strategies, FLAG-ERA fosters multi-disciplinary collaborations to expand the scope of the Graphene Flagship and the Human Brain Project. Among these was their latest Joint Transnational Call (JTC) 2021, announced earlier this year. JTC 2021 has resolved funding for the 10 projects, seven of which involve partners from widening countries like Bulgaria, Hungary, Slovakia, Slovenia and Turkey.