Recently observed white-light emission from graphene ceramics cannot be explained by black body radiation theory because of a relatively low temperature of the sample. Furthermore the intensity of the emission stays at the same level even at temperatures as low as 10 K, indicating the purely electronic nature of the observed emission. In this work a model of light emission from locally interacting stacked graphene layers after intense continuous wave laser excitation is proposed. After a light-induced sp to sp change of the hybridization sp-nanodomains surrounded by sp carbon atoms could be created and the electrons can be confined. Using DFT and TD-DFT methods followed by a molecular-like approach we examine the electronic structure and the optical properties of graphene (sp,sp)-clusters. We show the quantized and well separated energy levels of electrons from the domain's interior and the possibility of emission in the NIR/VIS/UV range.
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http://dx.doi.org/10.1039/c6cp07632g | DOI Listing |
Nat Commun
January 2025
Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control of Mechanical Structures, and Institute for Frontier Science, Nanjing University of Aeronautics and Astronautics, Nanjing, China.
The ferroelectricity in stacked van der Waals multilayers through interlayer sliding holds great promise for ultrathin high-density memory devices, yet mostly subject to weak polarization and cryogenic operating condition. Here, we demonstrate robust room-temperature ferroelectricity in monolayer graphene sandwiched between hexagonal boron nitride layers with a rhombohedral-like stacking (i.e.
View Article and Find Full Text PDFACS Nano
January 2025
Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea.
Bismuth oxyselenide (BiOSe) stands as a highly promising layered semiconductor with outstanding optical, electrical, and thermal properties. For the practical application of the material toward the devices, growing BiOSe directly on the amorphous substrate at low temperatures (<400 °C) is essential; however, the negatively charged bottom Se layer originating from alternating stacks of Se and [BiO] has hindered this process. In this work, we report the method for synthesizing a BiOSe film on amorphous alumina (AlO) directly at 350 °C by using chemical solution deposition.
View Article and Find Full Text PDFNano Lett
January 2025
Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies (C2N), 91120 Palaiseau, France.
The ability to tune the energy gap in bilayer graphene makes it the perfect playground for the study of the effects of internal electric fields, such as the crystalline field, which are developed when other layered materials are deposited on top of it. Here, we introduce a novel device architecture allowing simultaneous control over the applied displacement field and the crystalline alignment between two materials. Our experimental and numerical results confirm that the crystal field and electrostatic doping due to the interface reflect the 120° symmetry of the bilayer graphene/BN heterostructure and are highly affected by the commensurate state.
View Article and Find Full Text PDFSci Rep
January 2025
Materials Science and Engineering Program, College of Arts and Sciences, American University of Sharjah, POB 26666, Sharjah, United Arab Emirates.
Graphene, a two-dimensional material featuring densely packed sp-hybridized carbon atoms arranged in a honeycomb lattice, has revolutionized material science. Laser-induced graphene (LIG) represents a breakthrough method for producing graphene from both commercial and natural precursors via direct laser writing, offering advantages such as simplicity, efficiency, and cost-effectiveness. This study demonstrates a novel approach to synthesize a composite material exclusively from a porous organic polymer (POP) by direct femtosecond laser writing on a compressed imide-linked porous organic polymer substrate.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
National University of Singapore, Department of Materials Science and Engineering, 9 Engineering Drive 1, Singapore 117575.
By virtue of being atomically thin, the electronic properties of heterostructures built from two-dimensional materials are strongly influenced by atomic relaxation. The atomic layers behave as flexible membranes rather than rigid crystals. Here we develop an analytical theory of lattice relaxation in twisted moiré materials.
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