Cambridge University - Page 3

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.

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.

Australian advanced materials technology company, Talga Resources, recently announced positive initial test results from the development of its graphene silicon lithium-ion anode in the UK.

The results are the first under Talga’s UK Government-funded Safevolt project - a Talga-led program run in conjunction with consortia partners, Johnson Matthey, the University of Cambridge and manufacturing research group, TWI.

Graphene Flagship Partners at the National Inter-University Consortium for Telecommunications (CNIT) in Italy, IMEC in Belgium and University of Cambridge in UK have designed and tested a graphene-based phase modulator that reportedly outperforms existing silicon-based ones.

Modern optical data and telecommunications employ phase modulators to increase the amount of data relayed and data rate efficiency, i.e. the speed at which information is relayed. Phase modulators traditionally work by grouping several bits of information into fewer symbols, or packets, reducing the overall size, or spectral width. The smaller the spectral width, the higher the data rate efficiency. However, this efficiency is reaching a maximum with silicon based devices, and so a novel solution is needed to bridge the gap between the increase in demand for data and the efficiency in transmitting it.

Versarien, the advanced materials engineering group, has provided an update on its activities in relation to graphene-enhanced power storage devices like batteries and supercapacitors. The primary goal of incorporating graphene into these devices, Versarien says, is to significantly increase power storage capacity and reduce charging times.

Versarien has been working with WMG (Warwick Manufacturing Group) and their partner companies and scientists at the universities of Warwick and Cambridge to collaborate on the production of power storage devices such as batteries and supercapacitors using Versarien's proprietary Nanene graphene nano platelets. Significant advances have been made through incorporating the Company's high quality graphene into these devices and the Company looks forward to commercial products becoming available in due course.

Australia-based Talga Resources and its UK subsidiary Talga Technologies recently announced collaboration agreements to commence three UK Government Faraday Challenge battery programs. The execution of formal agreements follows the awarding of the grants under Faraday, a £246 million UK Government commitment over the next four years into battery development for automotive electrification. The initiative will encompass cell manufacture, modules, battery pack design/assembly and vehicle applications, and follows an undertaking by the UK Government to place a ban on new petrol and diesel engines by 2040.

Talga’s participation in the funding program of Innovate UK, the government development body, follows successful tests by Talga of its natural carbon materials and technologies in Li-ion batteries. Talga, together with its consortia partners, secured significant funding support under the ‘Innovation’ aspect of Faraday. Talga will receive a 70% rebate against its eligible costs, including salaries, consumables, equipment and contractor expenses. Talga’s participation in the programs range from 12-24 months and development activities will be led from Talga Technologies Limited in Cambridge UK, utilizing the Company's Swedish high grade graphite and functionalized graphene processed at Talga’s test facility in Germany.

A team led by researchers from the Indian Institute of Technology (IIT) in Bombay, India, has developed a graphene-enhanced inexpensive, flexible pressure sensor that can be used for various health-care applications. The piezoresistive pressure sensor can reportedly monitor even small-scale movements caused by low-pressure variations.

The sensor can measure blood pulse rate in real time when placed on the wrist and neck. The sensor was also tested for its ability to monitor respiration; When placed on the throat, the sensor could detect changes in pressure when different words were pronounced. Interestingly, the fabricated sensor also showed good sensitivity in detecting large-scale motion monitoring, as in the case of bending and extension of finger joints.

As part of a collaboration between the Graphene Flagship and the European Space Agency, experiments testing graphene for two different space-related applications have been performed. These have been reported to show very promising results, based on which the Flagship is to continue the development of graphene devices for use in space.

Graphene's excellent thermal properties are promising for improving the performance of loop heat pipes, thermal management systems used in aerospace and satellite applications. Graphene could also have a use in space propulsion, due to its lightness and strong interaction with light. The Graphene Flagship tested both these applications in recent experiments in November and December 2017.

Researchers from Cambridge University have demonstrated how graphene and other related 2D materials (namely hBN) can be directly printed onto textiles to create fully inkjet-printed dielectrically gated field effect transistors (FETs) with solution processed 2D materials.

According to the team, these devices are washable, flexible, cheap, safe, comfortable to wear and environmentally-friendly, essential requirements for applications in wearable electronics. The team also demonstrated the first reprogrammable memories, inverters and logic gates with solution processed 2D materials by coupling these FETs together to create integrated circuits, the most fundamental components of a modern-day computer.

Two interesting projects focused on coating single-layer graphene with metal-oxide nanolayers were presented at the latest Thin Films and Coating Technologies for Science and Industry event in the UK. Researchers from Cranfield University, UK, together with collaborators from University of Cambridge and the Centre for Process Innovation (CPI), applied alumina to form a composite barrier layer, while a team from Imperial College London, UK, used the unique properties of strontium titanate to fabricate a tuneable capacitor.

The researchers of the first project explained that in theory, graphene should represent an ideal ultrathin barrier layer, as the pores between carbon atoms are smaller even than the radius of a helium atom. In practice, however, crystal boundaries and missing atoms allow vapor to permeate through the material, and the weak van der Waals bonds between planes mean that even stacks of multiple graphene layers can be penetrated. The solution reported by the team is to take a graphene monolayer formed by CVD, and to then use atomic layer deposition (ALD) to coat it with a 2550 nm thick layer of alumina. Achieving conformal coatings on single-layer graphene is known to be difficult due to the material’s strong hydrophobicity.

OLED displays are very sensitive to oxygen and moisture, and the need to protect the displays is one of the major challenges of this next-generation display technology. First generation OLED displays were protected with a glass barrier, but glass is not easily flexible and so cannot be used in flexible OLEDs. Flexible OLEDs are today encapsulation with a thin-film encapsulation layer made from both organic and in-organic materials, and companies are searching for better OLED encapsulation technologies.

Graphene is the world's most impermeable material, and so the idea of using graphene as a barrier layer for OLED has been around for a while. In 2015 the UK launched a collaboration project called Gravia to develop graphene-based encapsulation, and the project's team has now reported their results.