Researchers deepen understanding of unconventional superconductivity in trilayer graphene

Researchers from Science and Technology (IST) Austria, in collaboration with scientists from the Weizmann Institute of Science in Israel, have developed a theoretical framework of unconventional superconductivity, which addresses the questions raised by earlier work that detected unique superconductivity in 'magic angle' trilayer graphene.

Superconductivity relies on the pairing of free electrons in the material despite their repulsion arising from their equal negative charges. This pairing happens between electrons of opposite spin through vibrations of the crystal lattice. Spin is a quantum property of particles comparable, but not identical to rotation. The mentioned kind of pairing is the case at least in conventional superconductors. "Applied to trilayer graphene," co-lead-author from IST, Areg Ghazaryan, points out, "we identified two puzzles that seem difficult to reconcile with conventional superconductivity."

Researchers achieve precision sieving of gases through atomic pores in graphene

A team of researchers, led by Professor Sir Andre Geim at The University of Manchester, in collaboration with scientists from Belgium and China, used low-energy electrons to make individual atomic-scale holes in suspended graphene. The holes came in sizes down to about two angstroms, smaller than even the smallest atoms like helium and hydrogen.

Exponentially selective molecular sieving through angstrom pores image

The researchers report that they achieved practically perfect selectivity (better than 99.9%) for such gases as helium or hydrogen with respect to nitrogen, methane or xenon. Also, air molecules (oxygen and nitrogen) pass through the pores easily relative to carbon dioxide, which is >95% captured.

Researchers demonstrate how graphene can improve perovskite solar cells

Recent research has shown that the incorporation of graphene-related materials improves the performance and stability of perovskite solar cells. Graphene is hydrophobic, which can enhance several properties of perovskite solar cells. Firstly, it can enhance stability and the passivation of electron traps at the perovskite’s crystalline domain interfaces. Graphene can also provide better energy level alignment, leading to more efficient devices.

Improving Solar Cells with Pristine Graphene on Lead Iodide Films image

In a recent study, Spain-based scientists used pristine graphene to improve the properties of MAPbI3, a popular perovskite material. Pristine graphene was combined with the metal halide perovskite to form the active layer of the solar cells. By analyzing the resulting graphene/perovskite material, it was observed that an average efficiency value of 15% under high-stress conditions was achieved when the optimal amount of graphene was used.

Researchers use 'aerographene' to create controllable electrical explosions

An international research team, led by Germany's Kiel University (CAU) and including scientists from the University of Southern Denmark, Technische Universität Dresden, University of Trento, Sixonia Tech and Queen Mary University of London, has used aero-graphene to develop a new method for the generation of controllable electrical explosions. "Aerographene" consists of a finely-structured tubular network based on graphene with numerous cavities. This makes it extremely stable, conductive and almost as lightweight as air.

The research team has now taken a major step toward practical applications. They have succeeded in repeatedly heating and cooling aerographene and the air contained inside it to very high temperatures in an extremely short period of time. This enables extremely powerful pumps, compressed air applications or sterilizing air filters in miniature.

Researchers demonstrate Doppler effect and sonic boom in graphene devices

A team of researchers from universities in Loughborough, Nottingham, Manchester, Lancaster and Kansas (US) has revealed that sonic boom and Doppler-shifted sound waves can be created in a graphene transistor.

When a police car speeds past you with its siren blaring, you hear a distinct change in the frequency of the siren’s noise. This is the Doppler effect. When a jet aircraft’s speed exceeds the speed of sound (about 760 mph), the pressure it exerts upon the air produces a shock wave which can be heard as a loud supersonic boom or thunderclap. This is the Mach effect. The scientists discovered that a quantum mechanical version of these phenomena occurs in an electronic transistor made from high-purity graphene.