Technical / Research

Researchers at Soochow University, University of Science and Technology of China, Peking University, ShanghaiTech University, Beijing Graphene Institute and additional collaborators have developed a copper-based growth process that produces large-area trilayer graphene films with uniform thickness and improved mechanical strength.

Schematic representation illustrating the synchronous growth process catalyzed by the heterogeneous Cu–Cu2O substrate. Inset: schematic of the graphene edge–Cu–Cu2O three-phase interfaces. Image from: Nature Communications

The team stated that much of graphene's functional promise - especially in electronics and optoelectronics - relies not on the single-layer form that dominates laboratory work, but on precise multilayer structures. Adding layers enables electronic band structures to be tuned and improves properties such as stiffness and thermal transport. Despite this, the controlled synthesis of multilayer graphene films with consistent thickness across large areas has remained quite elusive.

In systems with multiple energy bands, the interplay between electrons with different effective masses drives correlated phenomena that do not occur in single-band systems. Magic-angle twisted trilayer graphene is a tunable platform for exploring such effects, hosting both heavy ("bound") electrons and light ("weakly bound and mobile") electrons. 

Researchers at Harvard, MIT and National Institute for Material Science in Japan have examined the interplay between "light" and "heavy" electrons in magic-angle twisted trilayer graphene, shedding new light on how they may help form novel quantum states.

Vacuum is perceived as empty, but in fact it is full of fleeting energy fluctuations - virtual photons popping in and out of existence that can interact with matter, giving rise to new, potentially useful properties. Researchers use optical cavities, structures made of mirrors facing one another, to confine these fluctuations, harnessing their effects to engineer new forms of matter. Conventional optical cavities boost fluctuations, or vacuum fields, for both right- and left-handed circularly polarized light. 

Researchers at Rice University, Harvard University and Max Planck Institute have developed a new cavity design that selectively enhances the quantum vacuum fluctuations of circularly polarized light in a single direction, achieving chirality - a feat that typically requires the use of a strong magnetic field. The team used lightly doped indium antimonide to construct the chiral cavity. The researchers also conducted comprehensive theoretical investigations to predict how the new cavity design would transform the properties of materials placed inside it.

Researchers at Korea's Electronics and Telecommunications Research Institute (ETRI) have succeeded in developing an innovative transparent film using graphene. The film’s transparency changes depending on the intensity of light, and is expected to be used in a variety of fields, including laser protection devices, smart optical sensors, and artificial intelligence (AI) photonic materials.

Graphene has been challenging to utilize in real-world applications due to issues with adhesion. Although chemical dispersants have been employed to address this problem, they often compromise graphene’s intrinsic properties. The ETRI team's new photocurable graphene-dispersed colloid could address this issue and enable graphene to be stably and uniformly dispersed within a polymer without a dispersant. 

Atomically thin suspended graphene can be used as NEMS transducers for ultra-small and high-performance sensors thanks to its excellent mechanical and electrical properties. Most applications of suspended graphene in NEMS devices are limited to pressure sensors, resonators, switches, etc. Graphene-based NEMS accelerometers have rarely been reported, with limitations such as mechanical robustness, life span and device yield, thereby limiting their practical applications.

Researchers from the Beijing Institute of Technology and North University of China have developed piezoresistive graphene-based NEMS accelerometers with high manufacturing yield, excellent mechanical robustness and stability, and long life span, in which the width of trenches for suspending graphene membranes was only 1 µm and fully-clamped suspended double-layer graphene membranes with an attached SiO₂/Si proof mass was used as acceleration transducer. 

Researchers from the Complutense University of Madrid, University of Malaga, Autonomous University of Madrid, National University of Singapore (NUS) and Kyoto University have created a molecular model of bilayer graphene that is capable of controlling rotation, which in turn allows controlling conductivity and achieving "potentially spectacular semiconducting properties."

Structural analysis. Image from: Nature Chemistry

"By designing covalently bound molecular nanographenes we can simulate the search for the magic angle between graphene-like sheets, which is where semiconductivity is achieved, a key property in, for example, the construction of transistors, the basic units of computers," explains the team.

Zinc-ion batteries based on water-based electrolytes are inherently safe, environmentally friendly, and economically viable. They also mitigate fire risks and thermal runaway issues associated with their lithium-based counterparts, which makes them lucrative for grid-scale energy storage. Furthermore, zinc has high capacity, low cost, ample abundance, and low toxicity. Unfortunately, current collectors utilized in zinc-ion batteries, such as graphite foil, are difficult to scale up and suffer from relatively poor mechanical properties, limiting their industrial use.

Image credit: Dongguk University, Republic of Korea

In a new study, a team of researchers from the Republic of Korea, led by Associate Professor Geon-Hyoung An at the Department of Energy and Materials Engineering at Dongguk University, has proposed graphene-coated stainless steel foil as a novel alternative current collector. 

Researchers from the University of Vienna and Technical University of Vienna have used a unique technique to significantly enhance the stretchability of graphene for the first time by creating an accordion-like ripple effect. This achievement could open up new possibilities for applications that require specific levels of stretchability, such as wearable electronics. 

Graphene is notable for its high electrical conductivity but tends to be extremely stiff, as its atoms are arranged in a honeycomb pattern that contributes to this stiffness. It makes sense that removing some atoms from the material along with their bonds would result in reduced stiffness. Scientific research, however, has documented both a modest decline and a notable rise. Scientists have now resolved these contradictions with new measurements. Modern devices were used in the experiments and housed in the same ultra-clean, airless environment. As a result, samples can be moved between the various devices without contacting outside air.

Researchers from Hefei University and Chinese Academy of Sciences (CAS) have developed a novel 3D-printed graphene/polymer double-layer composite featuring high anisotropic thermal conductivity that offers improved photothermal and electrothermal performance for advanced ice control applications. 

Graphene is known for its outstanding thermal and electrical conductivity, particularly its strong anisotropy—high in-plane conductivity and much lower through-plane conductivity. To capitalize on this property, the researchers used dual-nozzle fused deposition modeling (FDM) 3D printing to directionally align graphene within a thermoplastic polyurethane (TPU) matrix. The resulting double-layer composite, consisting of graphene-enhanced TPU (G-TPU) and neat TPU (N-TPU), achieved an in-plane thermal conductivity of 4.54 W/(m·K), with an anisotropic ratio of about 8.

A team of researchers at École Polytechnique Fédérale de Lausanne (EPFL) recently developed a scalable technique to create porous graphene membranes that selectively filter CO₂ from gas mixtures. Their approach is said to reduce production costs while improving membrane quality and performance, paving the way for real-world applications in carbon capture and beyond.

Image from: Nature Chemical Engineering

Graphene membranes are excellent at separating gases because they can be engineered with pores just the right size to let CO₂ through while blocking larger molecules like nitrogen. This makes them ideal for capturing CO₂ emissions from power plants and industrial processes. But there’s a catch: manufacturing these membranes at a meaningful scale has been difficult and costly.