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Two-Dimensional Phosphorene, Arsenene, Antimonene Quantum Dots: Anomalous Size-Dependent Behaviors of Optical Properties
摘要： Employing size effect to tailor photo-absorption and -emission properties of quantum dots (QDs) nanostructures is a widely used method for optoelectronic and biomedical applications. In this work, based on time-dependent density functional theory calculations, we systematically research the size-dependent optical absorption and emission properties of two-dimensional phosphorene, arsenene, antimonene single-element QDs. As expected, the photo-absorption gap presents monotonically decreasing with the increase of QDs diameter which is consistent with the well-accepted quantum confinement effect (QCE). Surprisingly, the emission gap increases with the increase of size within ~3 nm diameter range. It is revealed that the anomalous phenomenon derives from the competition between the QCE and excited state structure rearrangement during the relaxation of excited state. The smaller two-dimensional QDs is more prone to structure deformation at excited state accompanied with the greater change of electronic structure, which prevails over the QCE and reduces the emission gap. The atomic level picture of anomalous emission phenomenon revealed in our research is valuable for the fundamental understanding size effect of QDs as well as for optical utilization in optoelectronics and biomedical field.
关键词： quantum dots,antimonene,optical properties,phosphorene,arsenene,size-dependent behaviors
更新于2025-09-16 10:30:52
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A First-Principles Study on the Adsorption of Small Molecules on Arsenene: Comparison of Oxidation Kinetics in Arsenene, Antimonene, Phosphorene and InSe
摘要： Arsenene, a new group V two-dimensional (2D) semiconducting material beyond phosphorene and antimonene, has recently gained an increasing attention owning to its various interesting properties which can be altered or intentionally functionalized by chemical reactions with various molecules. This work provides a systematic study on the interactions of arsenene with the small molecules, including H2, NH3, O2, H2O, NO, and NO2. It is predicted that O2, H2O, NO, and NO2 are strong acceptors, while NH3 serves as a donor. Importantly, it is shown a negligible charge transfer between H2 and arsenene which is ten times lower than that between H2 and phosphorene and about thousand times lower than that between H2 and InSe and antimonene. The calculated energy barrier for O2 splitting on arsenene is found to be as low as 0.67 eV. Thus, pristine arsenene may easily oxidize in ambient conditions as other group V 2D materials. On the other hand, the acceptor role of H2O on arsenene, similarly to the cases of antimonene and InSe, may help to prevent the proton transfer between H2O and O– species by forming acids, which suppresses further structural degradation of arsenene. The structural decomposition of the 2D layers upon interaction with the environment may be avoided due to the acceptor role of H2O molecules as the study predicts from the comparison of common group V 2D materials. However, the protection for arsenene is still required due to its strong interaction with other small environmental molecules. The present work renders the possible ways to protect arsenene from structure degradation and to modulate its electronic properties, which is useful for the material synthesis, storage and applications.
关键词： group V two-dimensional materials,electronic structure,first-principles calculations,O2 molecule splitting,arsenene
更新于2025-09-04 15:30:14
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Atomically Thin 2D‐Arsenene by Liquid‐Phased Exfoliation: Toward Selective Vapor Sensing
摘要： Phosphorene and antimonene, single- or few-layered (FL) semiconductor materials, have recently attracted enormous attention due to their unique properties, provided by their extreme thinness. Here, a liquid-phase exfoliation (LPE) procedure to prepare FL arsenene, another member of pnictogens, assisted by sonication and without any additional surfactant is reported. The exfoliation process is performed in various solvents. Among those, N-methylpyrrolidone is found to provide the highest concentration of stable arsenene sheets. Spectroscopic and microscopic analyses confirm the formation of high-quality few-layer arsenene nanosheets with large lateral dimensions. An application of this material for construction of vapor sensor based on electrochemical impedance spectroscopy is demonstrated. The device detects selectively methanol or acetone vapors depending on the selected resonance frequency. The results are highly reproducible, and the vapor sensor has long-term stability.
关键词： centrifugation,arsenic,2D arsenene,vapor sensors,liquid-phase exfoliation
更新于2025-09-04 15:30:14