graphene tagged posts

Graphene/WSe2 (2-D material)/graphene heterostructure. Credit: ICFO-Fabien Vialla

A 2D crystal, combined with graphene, has the capability to detect optical pulses with a response faster than 10 picoseconds, while maintaining a high efficiency, a new study demonstrates. Ultra-fast detection of light lies at the heart of optical communication systems nowadays. Driven by the internet of things and 5G, data communication bandwidth is growing exponentially, thus requiring even faster optical detectors that can be integrated into photonic circuits.

Prof Frank Koppens’s team has shown that a 2D crystal, combined with graphene, has the capability to detect optical pulses with a response faster than 10 picoseconds, while maintaining a high efficiency...

The perovskite film (black, 200-300 nm) is covered by Spiro.OMeTAD, Graphene with gold contact at one edge, a glass substrate and an amorphous/crystalline silicon solar cell. Credit: F. Lang / HZB

Measurements show the graphene layer is an ideal front contact in several respects. Silicon absorbers primarily convert the red portion of the solar spectrum very effectively into electrical energy, whereas the blue portions are partially lost as heat. To reduce this loss, the silicon cell can be combined with an additional solar cell that primarily converts the blue portions.

Teams at HZB have already acquired extensive experience with these kinds of tandem cells. A particularly effective complement to conventional silicon is the hybrid material called perovskite. It has a band gap of 1...

Schematic diagrams showing the synthesis and microstructures of a 3D graphene-RACNT fiber. (A) Aluminum wire. (B) Surface anodized aluminum wire (AAO wire). (C) 3D graphene-RACNT structure on the AAO wire. (D) Schematic representation of the pure 3D graphene-RACNT structure. (E to G) Top view SEM images of the 3D graphene-RACNT fiber at different magnifications. (I to K) SEM images of the cross-section of the 3D graphene-RACNT fiber. (H and L) AFM images of the 3D graphene-RACNT fiber. (M to P) SEM image (M) and corresponding EDX elemental mapping of (N) aluminum, (O) oxygen, and (P) carbon from the 3D graphene-RACNT fiber.

First 1-step process for making seamless carbon-based nanomaterials that possess superior thermal, electrical and mechanical properties in 3 dimensions...

Physicists build stable diffraction structure in atomically thin graphene.
The quantum mechanical wave nature of matter is the basis for a number of modern technologies like high resolution electron microscopy, neutron-based studies on solid state materials or highly sensitive inertial sensors working with atoms. Prof. Markus Arndt group focused on how one can extend such technologies to large molecules and cluster.

In order to demonstrate the quantum mechanical nature of a massive object it has to be delocalized first >> achieved by Heisenberg’s uncertainty relation: If molecules are emitted from a point-like source, they start to ‘forget’ their position after a while and delocalize...