The controlled imprinting of surfaces with specified patterns is important in the development of nanoscale devices. Previously, such patterns were created using self-assembled physisorbed adsorbate molecules that can be stabilized on the surface by subsequent chemical bonding. Here we show a first step towards use of the bonding within a surface to propagate reactions for patterning, namely the cooperative reaction of adjacent silicon atoms. We exploit the double-bonded silicon dimer pairs present on the surface of Si(100)-2×1 and show that the halogenation of one silicon atom (induced by electrons or heat) results in cooperative halogenation of the neighbouring silicon atom with unit efficiency. The reactants used were two 1-halopentane molecules physisorbed over a pair of silicon atoms. This cooperative pair of halogenation reactions was shown by ab initio calculation to be sequential on a timescale of femtoseconds.
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http://dx.doi.org/10.1038/nchem.440 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
East China University of Science and Technology, Key Laboratory for Advanced Materials and Institute of Fine Chemicals, 130 Meilong Road, 200237, Shanghai, CHINA.
Nanoconfinement at the interface of heterogeneous Fenton-like catalysts offers promising avenues for advancing oxidation processes in water purification. Herein, we introduce a template-free strategy for synthesizing nanoconfined catalysts from municipal sludge (S-NCCs), specifically engineered to optimize reactive oxygen species (ROS) generation and utilization for rapid pollutant degradation. Using selective hydrofluoric acid corrosion, we create an architecture that confines atomically dispersed Fe centers within a micro-mesoporous carbon matrix in situ.
View Article and Find Full Text PDFThis paper explores the process of forming arrays of vertically oriented carbon nanotubes (CNTs) localized on metal electrodes using thin porous anodic alumina (PAA) on a solid substrate. On a silicon substrate, a titanium film served as the electrode layer, and an aluminium film served as the base layer in the initial film structure. A PAA template was formed from the Al film using two-step electrochemical anodizing.
View Article and Find Full Text PDFJ Phys Chem A
January 2025
Institute of Materials Engineering, University of Silesia in Katowice, 75 Pułku Piechoty 1A, 41-500 Chorzów, Poland.
The ubiquitous nature of thermal fluctuations poses a limitation on the identification of crystal structures. However, the trajectory of an atom carries a fingerprint of its surroundings. This rationalizes the search for a method that can determine the local atomic configuration via the analysis of the movement of an individual atom.
View Article and Find Full Text PDFJ Chem Theory Comput
January 2025
Key Laboratory of Precision and Intelligent Chemistry, and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
Hybrid functionals that incorporate exact Hartree-Fock exchange (HFX) into density functional theory (DFT) are crucial for accurately predicting the electronic structures of extended systems in condensed-matter physics and materials science. Although the exact exchange contributes only a small fraction of the total energy, HFX calculations in hybrid functionals demand significant computational resources. Here, we introduce dual-grid and mixed-precision techniques, based on two low-rank approximations, adaptively compressed exchange (ACE) and interpolative separable density fitting (ISDF) methods, to significantly improve the computational efficiency of plane-wave hybrid functional calculations in the software package PWDFT (plane wave density functional theory).
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, India.
The tunability of the energy bandgap in the near-infrared (NIR) range uniquely positions colloidal lead sulfide (PbS) quantum dots (QDs) as a versatile material to enhance the performance of existing perovskite and silicon solar cells in tandem architectures. The desired narrow bandgap (NBG) PbS QDs exhibit polar (111) and nonpolar (100) terminal facets, making effective surface passivation through ligand engineering highly challenging. Despite recent breakthroughs in surface ligand engineering, NBG PbS QDs suffer from uncontrolled agglomeration in solid films, leading to increased energy disorder and trap formation.
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