Publications

Graphene-Based Liquid Crystal Device

Graphene is only one atom thick, optically transparent, chemically inert, and an excellent conductor. These properties seem to make this material an excellent candidate for applications in various photonic devices that require conducting but transparent thin films. In this letter, we demonstrate liquid crystal devices with electrodes made of graphene that show excellent performance with a high contrast ratio. We also discuss the advantages of graphene compared to conventionally used metal oxides in terms of low resistivity, high transparency and chemical stability.

Van der Waals Force Driven Ultrahigh-Density Piezoelectric Nano-Generators Arrays

No abstract is provided for this article.

Topological Spin Textures in an Insulating van der Waals Ferromagnet (Adv. Mater. 24/2024)

Topological Spin Textures Implementation of magnets with low-damping, minimum Joule heating and tunable topological spin properties consist one of the main goals towards novel information storage technologies. In article number 2311949, Sergey Grebenchuk, Elton J. G. Santos, Maciej Koperski, and co-workers report that a wide variety of topological magnetic textures can be created and controlled on-demand on CrBr3 van der Waals magnet insulators at different thicknesses, temperatures and external excitations, such as energy-efficient optical excitations.

Control of CO ₂ Electrocatalysis via Modularly Customizable Graphdiyne

On-demand customization of materials with tailored structures and properties is a long-standing goal in materials science. Yet conventional materials often exhibit complex configurations, hindering unified design principles and limiting performance optimization. Here, utilizing modular graphdiyne (GDY) as a configurable platform, we present a chemically guided molecular design framework to achieve atomic-level precision control over catalytic behaviors. By combining density functional theory (DFT) with experimental validation, we systematically introduced electron-donating and electron-withdrawing groups to construct 13 organic molecular units, yielding modularly customizable GDYs with predetermined structures, enabling us to disentangle the interplay between structure and catalytic function. We identified a volcano-shaped correlation, linking the oxidation state of the active alkyne carbons to CO₂ reduction (CO₂RR) activity. Furthermore, we established that this oxidation state is directly correlated with intrinsic electronic descriptors, including work function, VBM, and Fermi level (<i>E</i>_f)─constructing a predictive framework. In particular, by precisely tuning the oxidation state of <i>sp</i>-hybridized carbons, we showed that GDYs can rationally optimize intermediate binding energies and effectively resolve the conventional trade-off between the CO₂RR activity and HER suppression. This mechanistic approach enables systematic control of the CO/H₂ ratio from 1:10 to 13:1. Notably, the fluorinated GDY (3FGDY) achieves a remarkable 93% CO Faradaic efficiency with sustained stability over 90 h. These findings establish a direct atomic-level structure-performance relationship and provide a robust proof-of-concept for modular materials design, with promising implications for syngas production and sustainable energy conversion.

Highly Flexible and Conductive Printed Graphene for Wireless Wearable Communications Applications

In this paper, we report highly conductive, highly flexible, light weight and low cost printed graphene for wireless wearable communications applications. As a proof of concept, printed graphene enabled transmission lines and antennas on paper substrates were designed, fabricated and characterized. To explore its potentials in wearable communications applications, mechanically flexible transmission lines and antennas under various bended cases were experimentally studied. The measurement results demonstrate that the printed graphene can be used for RF signal transmitting, radiating and receiving, which represents some of the essential functionalities of RF signal processing in wireless wearable communications systems. Furthermore, the printed graphene can be processed at low temperature so that it is compatible with heat-sensitive flexible materials like papers and textiles. This work brings a step closer to the prospect to implement graphene enabled low cost and environmentally friendly wireless wearable communications systems in the near future.

Ore mineralogy and formation conditions of the Pirunkoukku gold occurrence (Finland)

No abstract is provided for this article.

Environmental Impacts of Personal Protective Clothing Used to Combat COVID-19

Personal protective clothing is critical to shield users from highly infectious diseases including COVID-19. Such clothing is predominantly single-use, made of plastic-based synthetic fibres such as polypropylene and polyester, low cost and able to provide protection against pathogens. However, the environmental impacts of synthetic fibre-based clothing are significant and well-documented. Despite growing environmental concerns with single-use plastic-based protective clothing, the recent COVID-19 pandemic has seen a significant increase in their use, that could result in a further surge of oceanic plastic pollution, adding to mass of plastic waste that already threatens marine life. In this review, we briefly discuss the nature of the raw materials involved in the production of such clothing, as well as manufacturing techniques and the PPE supply chain. We identify the environmental impacts at critical points in the protective clothing value chain from production to consumption, focusing on water use, chemical pollution, CO2 emissions and waste. On the basis of these environmental impacts, we outline the need for fundamental changes in the business model, including increased usage of reusable protective clothing, addressing supply chain bottlenecks, establishing better waste management, and the use of sustainable materials and processes without associated environmental problems.

Primary Au prospecting results in the Logrosán area (Central Iberian Zone, Spain).

No abstract is provided for this article.

Mineralogy and formation conditions of ore from the Biksizak silver-base-metal occurrence in the South Ural, Russia

No abstract is provided for this article.

Tearing Graphene Sheets From Adhesive Substrates Produces Tapered Nanoribbons

Graphene is a truly two‐dimensional atomic crystal with exceptional electronic and mechanical properties. Whereas conventional bulk and thin‐film materials have been studied extensively, the key mechanical properties of graphene, such as tearing and cracking, remain unknown, partly due to its two‐dimensional nature and ultimate single‐atom‐layer thickness, which result in the breakdown of conventional material models. By combining first‐principles ReaxFF molecular dynamics and experimental studies, a bottom‐up investigation of the tearing of graphene sheets from adhesive substrates is reported, including the discovery of the formation of tapered graphene nanoribbons. Through a careful analysis of the underlying molecular rupture mechanisms, it is shown that the resulting nanoribbon geometry is controlled by both the graphene–substrate adhesion energy and by the number of torn graphene layers. By considering graphene as a model material for a broader class of two‐dimensional atomic crystals, these results provide fundamental insights into the tearing and cracking mechanisms of highly confined nanomaterials.

Giant Spin-Hall Effect Induced by the Zeeman Interaction in Graphene

Observing Imperfection in Atomic Interfaces for van der Waals Heterostructures

Vertically stacked van der Waals heterostructures are a lucrative platform for exploring the rich electronic and optoelectronic phenomena in two-dimensional materials. Their performance will be strongly affected by impurities and defects at the interfaces. Here we present the first systematic study of interfaces in van der Waals heterostructure using cross sectional scanning transmission electron microscope (STEM) imaging. By measuring interlayer separations and comparing these to density functional theory (DFT) calculations we find that pristine interfaces exist between hBN and MoS2 or WS2 for stacks prepared by mechanical exfoliation in air. However, for two technologically important transition metal dichalcogenide (TMDC) systems, MoSe2 and WSe2, our measurement of interlayer separations provide the first evidence for impurity species being trapped at buried interfaces with hBN: interfaces which are flat at the nanometer length scale. While decreasing the thickness of encapsulated WSe2 from bulk to monolayer we see a systematic increase in the interlayer separation. We attribute these differences to the thinnest TMDC flakes being flexible and hence able to deform mechanically around a sparse population of protruding interfacial impurities. We show that the air sensitive two dimensional (2D) crystal NbSe2 can be fabricated into heterostructures with pristine interfaces by processing in an inert-gas environment. Finally we find that adopting glove-box transfer significantly improves the quality of interfaces for WSe2 compared to processing in air.

Infrared photodetection in graphene-based heterostructures: bolometric and thermoelectric effects at the tunneling barrier

Graphene/hBN/graphene tunnel devices offer promise as sensitive mid-infrared photodetectors but the microscopic origin underlying the photoresponse in them remains elusive. In this work, we investigated the photocurrent generation in graphene/hBN/graphene tunnel structures with localized defect states under mid-IR illumination. We demonstrate that the photocurrent in these devices is proportional to the second derivative of the tunnel current with respect to the bias voltage, peaking during tunneling through the hBN impurity level. We revealed that the origin of the photocurrent generation lies in the change of the tunneling probability upon radiation-induced electron heating in graphene layers, in agreement with the theoretical model that we developed. Finally, we show that at a finite bias voltage, the photocurrent is proportional to either of the graphene layers heating under the illumination, while at zero bias, it is proportional to the heating difference. Thus, the photocurrent in such devices can be used for accurate measurements of the electronic temperature, providing a convenient alternative to Johnson noise thermometry.

Strong Coulomb drag and broken symmetry in double-layer graphene

No abstract is provided for this article.

Piezoelectric Materials: Piezoelectricity in Monolayer Hexagonal Boron Nitride (Adv. Mater. 1/2020)

Monolayer hexagonal boron nitride (hBN) is a 2D crystal with a unique combination of properties. It is also predicted to be piezoelectric, yet experimental evidence has been lacking. In article 1905504, Francisco Guinea, Laura Fumagalli, Konstantin S. Novoselov, and co-workers use electrostatic force microscopy and directly visualize the piezoelectric field in monolayer hBN in nonhomogeneous strain regions around bubbles and creases.

AI for Science and Science for AI

In 2016, Hiroaki Kitano proposed that artificial intelligence (AI) will be able to overcome a number of human cognitive limitations that slow down the process of scientific discovery [Kitano 2016 web]. Since then, the odds of AI being awarded the Nobel Prize have been widely discussed, particularly within aca­demic community [Engineering for Research Symposium web 2020]. At the AI Journey 2021 conference, some renowned representatives of four scientific dis­ciplines (physics, mathematics, neurobiology, philosophy) discussed this issue and then co-authored this article [AI 2021 web]. In the first part of our paper, we critically analyze the role of AI technologies in natural science research: how useful they can be for fundamental science, what the potential of AI in natural and exact sciences is, and what principal limitations it has. Another part of our article discusses a counter-question of what science can do for the future re­search into AI. Today, it is impossible to imagine machine learning without lin­ear algebra, physics of materials, and brain research. All this falls under what is now commonly referred to as AI, a general umbrella term [Russel, Norvig 2021]. Thus, having served the birth of AI once, how can physics, mathematics, and neuroscience serve it today?

The New Architecture of Science

No abstract is provided for this article.

Atomically precise vacancy-assembled quantum antidots

No abstract is provided for this article.