Bosch Announces Breakthrough in Graphene Sensor Technology: 100X More Sensitive

Graphene Week 2015 was awash with outstanding research results, but one presentation created quite a stir at this Graphene Flagship conference. To a stunned audience, Robert Roelver of Stuttgart-based engineering firm Bosch reported on June 25, 2015, that company researchers, together with scientists at the Max-Planck Institute for Solid State Research, have created a graphene-based magnetic sensor 100 times more sensitive than an equivalent device based on silicon.

Bosch sensor portfolio

Bosch has long been involved in sensor technology, notably in the automotive sector. In 2008, the company expanded beyond its pressure, acceleration and gyroscopic motion sensors, to geomagnetic, temperature, humidity, air quality and sound pressure devices, including for use in consumer electronics devices such as mobile phones. Roelver noted that Bosch is the world’s number one supplier of microelectromechanical sensors, with €1bn in sales.

 

Bosch looks at graphene

Interested in whether graphene could enable new applications and improved sensor performance, Bosch has been investigating the use of the two-dimensional material in its pressure, magnetic, humidity, gas and sound pressure devices. The first step was to look at fabrication methods.

Top-down approaches to graphene device fabrication such as mechanical and chemical exfoliation would not work on a commercial scale, so Bosch focused instead on bottom-up techniques such as the thermal decomposition of silicon carbide, and chemical vapor deposition onto metal surfaces. The latter is certainly suited to mass production, and the former possibly so.

Roelver cautioned that graphene-based sensor applications will require 5-10 years before they can compete with established technologies. This is due to the current lack of large-scale wafer-based and transfer-free synthesis techniques.

A graphene-based magnetic sensor

Various substrates were considered by the Bosch and Max-Planck researchers, who in the case of their magnetic sensor settled on hexagonal boron nitride. This is for reasons of both cost and technical performance.

Bosch’s magnetic sensors are based on the Hall effect, in which a magnetic field induces a Lorentz force on moving electric charge carriers, leading to deflection and a measurable Hall voltage. Sensor performance is defined by two parameters: (1) sensitivity, which depends on the number of charge carriers, and (2) power consumption, which varies inversely with charge carrier mobility. It is high carrier mobility that makes graphene useful in such applications, and the results achieved by the Bosch-led team confirm this.

Comparing and contrasting materials, Roelver in his Graphene Week presentation showed that the worst case graphene scenarios roughly match a silicon reference. In the best case scenario, the result is a huge improvement over silicon, with much lower source current and power requirements for a given Hall sensitivity. In short, graphene provides for a high-performance magnetic sensor with low power and footprint requirements.

Graphene sensor 100 times more sensitive

In terms of numbers, the remarkable result shown by Roelver centered on a direct comparison between the sensitivity of a silicon-based Hall sensor with that of the Bosch-MPI graphene device. The silicon sensor has a sensitivity of 70 volts per amp-tesla, whereas with the boron nitride and graphene device the figure is 7,000. That is a jaw-dropping two orders of magnitude improvement, hence the reaction in the conference hall.

After summarizing this stunning research result, Roelver concluded on a high note, stressing that Bosch takes graphene very seriously indeed as a future commercial technology.

“We are pleased to see that Graphene Week has been chosen as the forum to disclose such an important technological milestone,” says Andrea Ferrari, chairman of the Executive Board of the Graphene Flagship. “Bosch’s call for large-area integration of graphene into industrial processes fully matches and validates the flagship’s planned investments in this critical area for the mass production of devices.”

SOURCE: Graphene Flagship

Nanotechnology: Characterizing the Very SMALL: The BIG Challenge

Nanotechnologies are everywhere, from the medicines we take to the food we eat, but what do we really know about the potential effects when they come into contact with complex matrices and how do we ensure that nanoproducts are safe?

The global market for nanomaterials is estimated by the European Commission to be 11 million tonnes at a market value of €20 billion, and products underpinned by nanotechnology are forecast to grow from a global volume of €200 billion in 2009 to €2 trillion by 2015. 

We know that the properties of nanomaterials can change significantly when they are used in complex matrices, such as biological systems, potentially affecting functionality and behaviour. It is these changes that are exploited in nanobiotechnology or nanomedical applications. For example, in some therapeutic applications, protein coated nanoparticles (apolipoprotein E coatings) can target specific locations, such as the brain.

However, there may be other currently unknown biological interactions which could pose a potential risk to human health. These risks are compounded by a lack of robust methods to characterise nanomaterials in complex biological matrices.

This was the challenge behind a three-year multi-national project, ‘Chemical and Optical Characterisation of Nanomaterials in Biological Systems’ (NanoChOp), which finished last month. The project is led by the international life sciences company LGC, which is the UK’s designated National Measurement Institute for chemical and bio- measurement, and involves a consortium of European partners.

Dr Heidi Goenaga-Infante, NanoChOp project coordinator and principal scientist for Inorganic Analysis at LGC, said: “The benefits of nanotechnology can only be fully realised if nanomaterials, particularly those for use in nanomedicine applications and consumer products, are shown to be non-toxic. Generally, nanomaterials are characterised in their pure form or in simple idealised matrices. However, if we are to understand the evolution of nanomaterials, it is important to be able to measure their physicochemical properties not only in a simple water environment but also within more complex biological matrices. This is a particularly challenging task, since matrix components are likely to interfere with numerous techniques and assays, leading to ambiguous readouts.”

To address this challenge, the project partners have developed methods to characterise nanomaterials for their physical, chemical and optical properties in biological matrices. They have also developed a series of nanoparticle quality control (QC) materials composed of metal oxide materials (which enable the development of methods for physical and chemical characterization), fluorescently labelled metal oxide materials (which allow nanomaterials tracking within biological systems), and a quantum dot nanomaterial (to enable the development of methods for the optical characterisation of fluorescent nanomaterials).

Goenaga-Infante said: “The traceable methods developed in the NanoChOp project will lead to a reduction in the uncertainty of measurements used to characterize nanomaterials in terms of their size, zeta potential, elemental composition, fluorescence etc. Such methods will be invaluable to evaluate the potential changes that nanomaterials may undergo due to interactions with biological systems.”

 

This new breakthrough will be welcome news to regulatory bodies who have been voicing concerns over the regulation of nanotechnologies for several years.

In 2009, the European Scientific Committee on Emerging and Newly Identified Health Risks published a report highlighting concerns about the methods for evaluating the potential risks of nanomaterials. It highlighted the need for further research to develop validated and standardised methodology for assessing risks associated with nanomaterials. The UK Nanotechnologies Strategy was launched in 2010 with the challenge of ensuring that society can benefit from novel applications of nanotechnology, while a high level of protection of health, safety and the environment is maintained.

Legislation has been introduced, albeit in a piecemeal fashion, which place restrictions on the use of nanomaterials. For example, the REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) Regulation (EC No. 1907/2006) provides an over-arching legislation applicable to the manufacture, placing on the market and use of substances on their own, in preparations or in articles. Nanomaterials are covered by the definition of a ‘substance’ in REACH even though there is no explicit reference to nanomaterials. The Cosmetic Regulation (EU No 1223/2009) was one of the first to be introduced and states that all ingredients present as nanomaterials must be clearly indicated with the term ‘nano’ in the ingredients list on the product packaging. Others include the Biocidal Products Regulation (EU No 528/2012) and there are additional areas of legislation where proposals are being made including controlling the use of nanomaterials including in medical devices.

The new methods and QC materials from the NanoChop project will assist in providing regulatory bodies and legislators with coherent and comparable data from which to formulate policy, enabling manufacturers of nanomaterials to operate under a fit for purpose regulatory framework.

Goenaga-Infante said: “Ultimately, the NanoChOp project will help to alleviate public concern regarding the safety of many applications of nanoparticles by providing the nanobiotechnology and the nanomedicine sectors with validated protocols to perform their analysis. In turn, this will lead to regulatory and legislative bodies being equipped with reliable data upon which to make more informed decisions.”

The NanoChOp project is funded by the European Metrology Research programme (EMRP).

Water & Wastewater Treatment: Organics & Micro-Pollutants: Graphene Materials Company Ariva Secures £4m Funding

Innovative water and wastewater treatment company Arvia^TM Technology has secured £4 million in its latest round of investment funding. The company is now embarking on a series of demonstration installations in industrial treatment facilities.

Arvia has developed its own graphene-based proprietary material – Nyex^TM – which removes organics, emerging contaminants and micro-pollutants from wastewater and is regenerated in-situ in the novel organics destruction cell (ODC) process. The technology was spun-out of Manchester University’s School of Chemical Engineering.

Arvia’s modular treatment units can remove and oxidise low, trace toxic and problematic pollutants. These include metaldehyde, which is used by farmers in slug pest control and endocrine-disrupting and problem chemicals used in thepharmaceutical industry andpersonal care products, including triclosan.

Arvia Chief Executive Mike Lodge said:

“This is a very exciting time for Arvia Technology. We now have in place the secure financial backing required to strengthen our team and launch Arvia’s game-changing products into the water sector.”

“We have numerous test units to deploy into the market and we are looking for early adopters to collaborate with Arvia in applying this technology, which is changing the boundaries of how water is treated.”

The advanced treatment units can treat emerging contaminants and priority substances can be configured with the appropriate number of ODCs based on organics concentrations in a given waste stream. Units can be placed in series to manage a range of flow volumes from a few cubic metres per day to over 2,000 cubic metres per hour.

Organics can be treated at source and Arvia is now identifying companies in the industrial, pharmaceutical, herbicide and chemical sectors with problematic wastes.