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:

Graphene-based intelligent quantum sensor can simultaneously detect the intensity, polarization and wavelength of light

A team of researchers from Yale University, The University of Texas at Dallas and the National Institute for Materials Science in Tsukuba, Japan, has built a graphene-based intelligent sensor that can simultaneously detect the intensity, polarization and wavelength of light, tapping into the quantum properties of electrons. The team estimates this breakthrough could help advance the fields of astronomy, health care, and remote sensing.

The researchers used twisted double bilayer graphene (TDBG)—that is, two atomic layers of natural stacked carbon atoms given a slight rotational twist—to build their sensing device. The twist reportedly reduces the crystal symmetry, and materials with atomic structures that are less symmetrical—in many cases—promise some intriguing physical properties that aren't found in those with greater symmetry.

SensFit Technologies partners with Footwork Podiatric Laboratory to develop graphene-enhanced smart orthotics

SensFit Technologies developed a smart shoe with inbuilt sensors, aiming to improve the quality of life of older people through the early detection of dementia, diabetic ulcers and other physical activity issues. Now, SensFit has announced that it is partnering with Footwork Podiatric Laboratory, a leading Australian custom-made orthotic manufacturer to develop Smart Orthotics to help diabetic ulcer treatment.

SensFit Technologies partners with Footwork Podiatric Laboratory on graphene-enhanced smart orthotics image

This product combines two innovative technologies: Sensfit’s unique graphene sensors integrated with AI and data analysis technology, combined with Footwork’s 3D printing technology to custom manufacture large volume orthotics.

Zentek’s rapid diagnostic platform receives two NSERC grants

Zentek has announced that McMaster University has received two Natural Sciences and Engineering Research Council (“NSERC”) Grants related to the aptamer-based rapid detection technology exclusively licensed by Zentek, pursuant to its license agreement with McMaster: The Alliance Missions Grant for the amount of CAD$1,000,000 (around USD$782,000) and an Idea to Innovation (I2I) Grant for the amount of CAD$350,000 (around USD$274,000) of which Zentek will make a CAD$140,000 (around USD$109,000) contribution. Both of these awards are the maximum awarded under each respective grant program, with disbursements delivered over the next two years.

“The research team at McMaster University has achieved significant milestones for the rapid diagnostic platform including the creation of a new ‘universal’ aptamer with a high binding affinity to all known Covid variants,” said Greg Fenton, CEO of Zentek. “Zentek is proud to continue working with the global-leading research team at McMaster University, with significant financial support from NSERC, which is a great endorsement of our technology and goal of commercialization.”

Reduced graphene oxide enables stretchable strain sensor for monitoring of physical activities

A new work by scientists at India's National Institute of Technology Rourkela describes the fabrication of extremely flexible, accurate, and robust strain sensors employing electrochemically produced reduced graphene oxide (rGO).

Conventional silicon-based strain sensors have relatively low flexibility of less than 5% and inadequate responsiveness, making them unsuitable for detecting both small and large strains. Aside from the flexibility constraint, typical silicon-based strain sensors need sophisticated manufacturing procedures such as microelectromechanical and deposition of thin films. Flexibility, responsiveness, and endurance are critical characteristics of wearable devices because they aid in the integration of the sensors over non-uniform interfaces such as the human body. Aside from elasticity, these products also need a sensor capable of detecting minute deformations caused by physiological factors and physical activity.

Researchers develop a graphene platform for extra sensitive detection of viral proteins

Scientists at Swansea University, Biovici Ltd and the National Physical Laboratory have developed a graphene-based method to detect viruses in very small volumes.

Researchers develop graphene platform of biosensors imageGraphene device chip attached to an electrical connector, with two 5 μL HCVcAg samples (one applied on each graphene resistor). Image credit: Swansea U

The work followed a successful Innovate UK project developing graphene for use in biosensors – devices that can detect tiny levels of disease markers.