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

The SGPCM project aims to use graphene plasmons for novel applications in medical imaging, biosensing, signal processing and computing

An EU-funded project called the SGPCM project ("Switching Graphene-plasmon with Phase-Change Materials") is focusing on the unique capabilities of graphene plasmons to transport and control light emissions at spatial scales far smaller than their wavelength. This project is working on developing ways to use graphene efficiently in novel optical technologies with potential applications in medical imaging, biosensing, signal processing and computing.

Plasmons are quasiparticles that form the smallest quantum of plasma oscillations – just as a photon is the smallest quantum of light. Graphene plasmons interact strongly with light and can therefore be used to guide it in entirely novel ways, opening pathways to the development of promising new technologies. They can be exploited in countless applications, including for infrared biosensing and absorption spectroscopy to identify the chemical information of biomolecules by detecting their vibrational fingerprints, and for sub-wavelength optical imaging, which enables the imaging of details much smaller than the wavelength of the illuminating light.

Liquid X and Bonbouton to collaborate on graphene-enhanced textile-based sensors

Liquid X Printed Metals, an advanced material manufacturer of functional metallic inks, has announced a collaboration effort with Bonbouton (a company focused on developing thermal sensing applications using a smart textile platform) to build graphene-enhanced temperature and pressure sensors directly on textiles using additive manufacturing techniques.

Through Bonbouton's inkjet-printable graphene technology, licensed from the Stevens Institute of Technology, the Company is developing thin and mechanically flexible sensors for wearable physiology monitoring. This gives consumers wearable personal health options that are unobtrusive, comfortable and attractive, while still enabling the collection of accurate, precise and useful data.

Graphene for the Display and Lighting Industries

Researchers use graphene to detect mid-infrared light at room temperature and convert it into electricity

Researchers from ICFO and Yale have used graphene to efficiently detect mid-infrared light at room temperature and convert it into electricity. Detecting infrared light is of major importance for current applications in spectroscopy, materials processing, chemical, bio-molecular and environmental sensing, security and industry since the mid-infrared spectral region is the range where characteristic vibrational transitions and rotational excitations of many important molecules occur.

Graphene mid-infrared detector imageSchematic of the proposed device, composed of graphene-disk plasmonic resonators connected by quasi-1D graphene nanoribbons

These vibrational and rotational excitations of many molecules, including hazardous and biological molecules, have frequencies that are found in the mid-infrared, which can be monitored by observing the absorption of light in this specific spectral range. However, currently available mid-infrared detectors are very inefficient, except those that can operate at cryogenic temperatures, because they incorporate superconducting elements. Thus, this low temperature limitation is a major drawback in having detectors integrated in devices for consumer products.

Project NanoGraM promotes applications of suspended graphene membranes

Graphenea, in collaboration with industrial and academic partners (Infineon Technologies, WITec, RWTH Aachen University and Simune Atomistics), announced the successful completion of project NanoGraM that focused on nano/microelectromechanical (NEMS/MEMS) devices based on graphene. The project focused on three specific device concepts for potential future products: graphene microphones, graphene-membrane pressure sensors and graphene-membrane Hall sensors.

Project NanoGram image

The target markets for these devices include portable electronics (smartphones, laptops), automotive, industrial, and smart homes, among others.

Versarien enters agreement with AXIA Materials on smart building and EV applications

Versarien LogoVersarien, the advanced materials engineering group, has announced that it has entered into a collaboration agreement with AXIA Materials to develop graphene-enhanced composite materials and smart graphene devices using both Versarien's proprietary Nanene graphene nano platelets and proprietary Graphinks graphene inks.

AXIA, based in South Korea, develops advanced thermoplastic composite material solutions under its LiteTex brand for the automotive, sports, electronics and building sectors, and produces pre-fabricated buildings under its Pixel Haus brand.

Versarien - Think you know graphene? Think again! Versarien - Think you know graphene? Think again!