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Researchers compute unprecedented values for spin lifetime anisotropy in graphene

The team’s calculations indicate a spin lifetime anisotropy that is orders of magnitude larger than anything observed in graphene until now.

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Compacted dimensions and singular plasmonic surfaces

In advanced field theories, there can be more than four dimensions to space, the excess dimensions described as compacted and unobservable on everyday length scales. We report a simple model, unconnected to field theory, for a compacted dimension realized in a metallic metasurface periodically structured in the form of a grating comprising a series of singularities. An extra dimension of the grating is hidden, and the surface plasmon excitations, though localized at the surface, are characterized by three wave vectors rather than the two of typical two-dimensional metal grating. We propose an experimental realization in a doped graphene layer.

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Tunable excitons in bilayer graphene

Excitons, the bound states of an electron and a hole in a solid material, play a key role in the optical properties of insulators and semiconductors. Here, we report the observation of excitons in bilayer graphene (BLG) using photocurrent spectroscopy of high-quality BLG encapsulated in hexagonal boron nitride. We observed two prominent excitonic resonances with narrow line widths that are tunable from the mid-infrared to the terahertz range. These excitons obey optical selection rules distinct from those in conventional semiconductors and feature an electron pseudospin winding number of 2. An external magnetic field induces a large splitting of the valley excitons, corresponding to a g-factor of about 20. These findings open up opportunities to explore exciton physics with pseudospin texture in electrically tunable graphene systems.

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Pairing up electrons and holes in bilayer graphene

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Graphene water filter turns whisky clear

In the newly developed ultrathin membranes, graphene-oxide sheets are assembled in such a way that pinholes formed during the assembly are interconnected by graphene nanochannels, which produces an atomic-scale sieve allowing the large flow of solvents through the membrane.

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3…2…1…Launch! Graphene goes zero G!

After a long summer of hard work in the laboratories, researchers in the Graphene Flagship are ready for two experiments this week, testing graphene technologies for space-related applications in collaboration with the European Space Agency.

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Key to direct graphene transfer is the control of water intercalation

A proposed intercalation-based electrochemical transfer method forms the basis of a novel optimized direct graphene transfer method.

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Perovskite solar cells with CuSCN hole extraction layers yield stabilized efficiencies greater than 20%

Perovskite solar cells (PSCs) with efficiencies greater than 20% have been realized only with expensive organic hole-transporting materials. We demonstrate PSCs that achieve stabilized efficiencies exceeding 20% with copper(I) thiocyanate (CuSCN) as the hole extraction layer. A fast solvent removal method enabled the creation of compact, highly conformal CuSCN layers that facilitate rapid carrier extraction and collection. The PSCs showed high thermal stability under long-term heating, although their operational stability was poor. This instability originated from potential-induced degradation of the CuSCN/Au contact. The addition of a conductive reduced graphene oxide spacer layer between CuSCN and gold allowed PSCs to retain >95% of their initial efficiency after aging at a maximum power point for 1000 hours under full solar intensity at 60°C. Under both continuous full-sun illumination and thermal stress, CuSCN-based devices surpassed the stability of spiro-OMeTAD–based PSCs.

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Graphene-based composite materials unlock the path to ultra-low-power transistors

An international team of scientists has discovered a new route to ultra-low-power transistors using a graphene-based composite material.

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Graphene performs under pressure

Scientists have fabricated highly miniaturised pressure sensors using graphene membranes which can detect minute changes in pressure with high sensitivity, over a wide range of operating pressures.

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