Colloidal cubic diamond crystals with low-coordinated and staggered structures could display a wide photonic bandgap at low refractive index contrasts, which makes them extremely valuable for photonic applications. However, self-assembly of cubic diamond crystals using simple colloidal building blocks is still considerably challenging, due to their low packing fraction and mechanical instability. Here we propose a new strategy for constructing colloidal cubic diamond crystals through cooperative self-assembly of surface-anisotropic triblock Janus colloids and isotropic colloidal spheres into superlattices. In self-assembly, cooperativity is achieved by tuning the interaction and particle size ratio of colloidal building blocks. The pyrochlore lattice formed by self-assembly of triblock Janus colloids acts as a soft template to direct the packing of colloidal spheres into cubic diamond lattices. Numerical simulations show that this cooperative self-assembly strategy works well in a large range of particle size ratio of these two species. Moreover, photonic band structure calculations reveal that the resulting cubic diamond lattices exhibit wide and complete photonic bandgaps and the width and frequency of the bandgaps can also be easily adjusted by tuning the particle size ratio. Our work will open up a promising avenue toward photonic bandgap materials by cooperative self-assembly employing surface-anisotropic Janus or patchy colloids as a soft template.
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Nanoscale
December 2024
Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284-2006, USA.
SiGe alloy nanocrystals (NCs) are a class of benign semiconductors that show size and composition-tunable energy gaps and promising optical properties because of the lattice disorder. The random distribution of elements within the alloys can lead to efficient light-matter interactions, making them attractive for Si-compatible optoelectronic devices, transistors, charge storage, and memory applications. However, the fabrication of discrete, quantum-confined alloys has proved a challenging task.
View Article and Find Full Text PDFACS Appl Mater Interfaces
December 2024
Neurotherapeutics Laboratory, Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005, India.
Herein, we unveil a remarkable finding for synthesizing room-temperature-stable, nontoxic, ultrasmall free-standing diamond cubic tin nanocrystals (α-Sn) with beta forms in the aqueous phase, avoiding conventional approaches that typically use toxic elements or large reactive substrates (Si/InSb) to stabilize α-Sn above 13 °C. Herein, for the first time, we demonstrate the successful synthesis of free-standing alpha tin with extraordinary stability up to 80 °C and in the aqueous phase at room temperature, which was supported by powder X-ray diffraction and X-ray photoelectron spectroscopy characterization methods. This synthetic approach eliminates the need to use hazardous materials, bulky substrates, and elevated temperatures, offering a safer, low-cost, and more sustainable alternative.
View Article and Find Full Text PDFJ Mech Behav Biomed Mater
November 2024
School of Mechanical Engineering, University of Campinas - UNICAMP, Campinas, SP, Brazil. Electronic address:
Given the capability to produce parts with complex geometries, powder bed fusion using a laser beam (PBF-LB), one of several additive manufacturing techniques, is becoming increasingly prevalent in both research and industry. Advances in the development of biomedical lattice structures show a trend in the use of functional gradients for greater customization and adjustment of mechanical properties according to the demands. This study analyzed four biomedical potential lattice structures (regular and graded) manufactured using PBF-LB in Ti6Al4V alloy.
View Article and Find Full Text PDFJ Colloid Interface Sci
November 2024
Institute of Aerospace Thermodynamics, University of Stuttgart, Pfaffenwaldring 31, Stuttgart, 70569, Germany.
Hypothesis: The shape of the wetted region after a droplet impact can vary significantly even in the early phase of the process. How much of the early spreading process occurs within the structures versus above the structures, flow regimes and local wetting at groove intersections can have effects on the sizes and shapes of the final wetted regions. Experiments and simulations: We experimentally study droplet impacts onto cubic pillars with , and side length, height and separation.
View Article and Find Full Text PDFNano Lett
November 2024
Department of Engineering Physics, Ecole Polytechnique de Montreal, C. P. 6079, Succ. Centre-Ville, Montréal, Québec H3C 3A7, Canada.
The work unravels the previously unexplored atomic-scale mechanism involving the interaction of phonons with crystal homointerfaces. Silicon nanowires with engineered isotopic content and crystal phases were chosen for this investigation. Crystal polytypism, manifested by the presence of both diamond cubic and rhombohedral phases within the same nanowire, provided a testbed to study the impact of phase homointerfaces on phonon transport.
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