International research undertaken by scientists from ICFO and CIC nanoGUNE, amongst other centres, has enabled compressing light into small devices and controlling their flow of electricity, thanks to the union of graphene and boron nitride (a good bidimensional insulator). Such a promising heterostructure has been made possible through taking advantage of what are known as plasmons: quasiparticles in which electrons and light move together as a coherent wave. The plasmons, guided by the graphene, can be limited to nanometric wave scales, up to 200 times smaller than the wavelength of light. An important obstacle to date, however, has been the rapid loss of energy that these plasmons undergo, thus limiting the range within which they can travel. This problem has been solved thanks to the union between graphene and boron nitride. The combination of these two unique bidimensional materials has provided the solution to controlling light in small devices, as well as obviating energy losses. When the graphene is encapsulated within boron nitride, the electrons can travel, ballistically, large distances without dispersion, including at ambient temperature. This research (, "Highly confined low-loss plasmons in graphene–boron nitride heterostructures") shows that the graphene/boron material nitride system is also an excellent host to extremely strongly confined light as well as to suppressing loss of plasmons. The research was carried out by researchers from ICFO (Barcelona), nanoGUNE and CNR/Scuola Normale Superiore (Pisa) — all members of the EU Graphene Flagship, and the US universities of Columbia and Missouri. According to Ikerbasque researcher Rainer Hillenbrand, Nano-optics team leader at nanoGUNE, “we are now able to compress light and, at the same time, propagate it for considerable distances by employing nanomaterials. In the future, thanks to the fact that plasmon loss is insignificant, much faster signal processing and information processing can be achieved, with greater optical sensitivity”. According to the authors of the research, this is only the beginning of a series of discoveries about the nano-optoelectronic properties of this new heterostructure, previously discovered at the University of Columbia. These discoveries open the path to extremely miniaturised optical circuits and devices which can be useful for biological detection, information processing and data communication.
Graphene-boron nitride heterostructures propagate light at the nanoscale
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Stable long term operation of graphene devices achieved
Graphene based devices have shown outstanding electrical and optical performances. However, the properties of graphene devices are extremely sensitive to environmental factors, such as humidity or gas composition, making a reproducible operation in normal atmosphere impossible so far. Researchers from AMO GmbH and Graphenea SE have now demonstrated a sophisticated encapsulation technique enabling highly reproducible operation of graphene devices in normal atmosphere for several months. 
Generally, adsorbates from the ambient (such as moisture or oxygen) and residuals from lithography processes used during device fabrication adhere to the graphene and change its doping level unintentionally. As these contaminants are unstable under normal conditions, the doping level and hence the electrical and optical properties of graphene devices also change. The variation in these parameters is a major roadblock for using graphene devices in applications. The researchers at AMO GmbH and Graphenea SE have identified this problem and investigated the encapsulation of graphene field effect devices using aluminum oxide, an encapsulation material well known for OLEDs. The key parameter for device passivation found in this study is the growth of an oxide layer using a properly in-situ oxidized aluminum seed layer. The employed passivation layer is able to persistently stabilize the device characteristics over several months when stored and measured in ambient atmosphere. This is a major step towards the use of graphene devices in real applications. The research work is published in the Royal Society of Chemistry journal ("Highly Air Stable Passivation of Graphene Based Field Effect Devices"). The work is financially supported by the European Commission under the projects GRAFOL (contract no. 285275), Flagship Graphene (contract no. 604391), and by the German Science Foundation under the project Ultragraphen (contract no. BA3788/2-1).
Generally, adsorbates from the ambient (such as moisture or oxygen) and residuals from lithography processes used during device fabrication adhere to the graphene and change its doping level unintentionally. As these contaminants are unstable under normal conditions, the doping level and hence the electrical and optical properties of graphene devices also change. The variation in these parameters is a major roadblock for using graphene devices in applications. The researchers at AMO GmbH and Graphenea SE have identified this problem and investigated the encapsulation of graphene field effect devices using aluminum oxide, an encapsulation material well known for OLEDs. The key parameter for device passivation found in this study is the growth of an oxide layer using a properly in-situ oxidized aluminum seed layer. The employed passivation layer is able to persistently stabilize the device characteristics over several months when stored and measured in ambient atmosphere. This is a major step towards the use of graphene devices in real applications. The research work is published in the Royal Society of Chemistry journal ("Highly Air Stable Passivation of Graphene Based Field Effect Devices"). The work is financially supported by the European Commission under the projects GRAFOL (contract no. 285275), Flagship Graphene (contract no. 604391), and by the German Science Foundation under the project Ultragraphen (contract no. BA3788/2-1).Graphene nanosensor determines caffeine and other componets in tea
Researchers from University of Tehran used a simple, cost-effective and eco-friendly method to produce a sensor based on graphene nano-sheets with high sensitivity and simultaneously measure useful components of tea (, "Simultaneous determination of theophylline, theobromine and caffeine in different tea beverages by graphene-oxide based ultrasonic-assisted dispersive micro solid-phase extraction combined with HPLC-UV"). Tea is a traditional drink in many countries. Alkaloid compounds, including methylxanthine, are known as the cause of useful properties of the drink such as decreasing the risk of cancer and cardiovascular diseases, anti-oxidant, anti-inflammation and anti-overweighting. Theophylline, theobromine and caffeine existing in tea are among the type of methylxanthines that are found in almost all types of teas. The aim of the research was to produce a sensor and measure the abovementioned components to evaluate the quality of the tea. Finding a pattern for the useful components of home-made tea and comparing it with the foreign-made products is among other objectives of the research. According to Dr. Hassan Sereshti, chemical composition and the mechanism to process tea provides the required information to understand therapeutic characteristics of the tea. However, no scientific and reliable method has so far been presented to study the quality of tea. Therefore, the results of the research can be used for the production of domestically-made tea and to improve its quality. The development of the method and taking samples from tea products at various geographical areas at different times of the process result in obtaining a national standard pattern for tea. Due to the potentials of graphene oxide, this sorbent can be used as a suitable method for the measurement and separation of polar and hydrophilic molecule samples from aqueous solutions.
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