Searcharxiv⌕ Search
Home/Archive/arXiv

arXiv · cond-mat/0606613

Influence of Annealing Conditions on Structure and Optical Properties of Copper Nanoparticles Embedded in Silica Matrix

Oleg A. Yeshchenko·Igor. M. Dmitruk·Andriy M. Dmytruk·Alexandr A. Alexeenko
View original source ↗Read source document ↗Export metadata ↓

Abstract

Copper nanoparticles have been grown in silica matrix by annealing of the sol-gel prepared porous matrix impregnated with the copper nitrate. The annealing has been performed in air, successively in air and hydrogen, and in hydrogen. Cu nanoparticles in size range of 2-65 nm have been grown depending on annealing conditions. Annealing in air results in copper oxide nanoparticles (Cu2O) growth as well. Transmission electron microscopy (TEM) and optical spectroscopy of the copper nanoparticles in silica matrix have been performed. The copper nanoparticles of two types are grown: spherical mature particles and elliptical seed particles. The surface plasmon peak has been observed clearly in absorption spectra of Cu nanoparticles. Surface plasmon peak in absorption spectra of Cu nanoparticles demonstrates slight blue shift with decrease of the particle size. The half-width of the surface plasmon peak decreases appreciably at the lowering of temperature from 293 K to 77 and 4.2K that is due to strong electron-phonon interaction. The low-frequency Raman scattering data are in agreement with electron microscopy and absorption data. Photoluminescence from the copper nanoparticles has been observed. Efficiency of the luminescence increases appreciably at the decrease of particle size. The observed increase is explained, probably, by the coupling of the excited incoming and outgoing emitted photons with surface plasmon.

Explore related subjects

cond-mat.mtrl-sci

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Oleg A. Yeshchenko, Igor. M. Dmitruk, Andriy M. Dmytruk, Alexandr A. Alexeenko. 2006-06-23. Influence of Annealing Conditions on Structure and Optical Properties of Copper Nanoparticles Embedded in Silica Matrix. https://arxiv.org/abs/cond-mat/0606613

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Measuring chiral phonons

Chiral phonons are quantized vibrations where the atomic motion in a solid breaks improper rotation symmetries. In many cases, chiral phonons possess angular momenta and are therefore selective to circularly polarized light. Both fundamental and applied research efforts on chiral phonons have been gaining increasing attention owing to their importance in a variety of fields including spintronics, spin-selective chemical reactions, thermal transport, quantum information processing and biosensing, where the bi-directional spin-lattice coupling enabled by chiral phonons can be harnessed in new ways, and potentially lead to new functionalities. Thus far, the studies of chiral phonons across diverse materials platforms have evolved largely independently within these fields, but the experimental techniques are often interrelated. In this perspective, we present a detailed description, as well as advantages and disadvantages of the current approaches for experimentally measuring chiral phonons in chiral and achiral materials. We conclude with a discussion of new methods for measuring chiral phonons. Ultimately, this work seeks to offer an experimental guide for systematically investigating the properties of chiral phonons in various materials systems and applications.

cond-mat.mtrl-sci↗
arXiv2026

A model of grain growth in UN integrating molecular dynamics, phase-field modeling, and uncertainty quantification

Grain growth kinetics and grain-boundary (GB) properties in uranium mononitride (UN) are investigated through an integrated multiscale framework combining molecular dynamics (MD), phase-field modeling, and surrogate-assisted uncertainty quantification. MD simulations yield GB energies for 27 symmetric tilt boundaries from 0--2000~K, which are consistent with available DFT values. The average GB energy is nearly temperature-independent below 1000~K and increases at higher temperatures. A mechanistic pore-drag model applied to the only available grain growth dataset for actinide nitrides yields a mobility reduction factor of $s \approx 0.93$--$0.99$, statistically indistinguishable from unity, confirming that pore drag is negligible under the experimental conditions. The intrinsic GB mobility is therefore extracted directly from the effective mobility, yielding $M_0 = 2.05\times10^{-15}$~m$^4$/(J$\cdot$s) and $Q_M = 0.89$~eV. Phase-field simulations conducted from 1500--2000~K confirm normal curvature-driven grain growth, with grain size distributions converging to the Hillert-like form. A surrogate-assisted global sensitivity analysis---combining principal component analysis, Gaussian process regression, and Sobol decomposition---reveals that the mobility prefactor $M_0$ dominates output variance at all times, followed by the activation energy $Q_M$, while the GB energy $\gamma$ contributes minimally. These results establish the first quantitative grain growth framework for UN and identify the reduction of uncertainty in $M_0$ and $Q_M$ as the highest-priority target for future experimental efforts.

cond-mat.mtrl-sci↗
arXiv2026

Silicon Solar Cell Design for >30% Efficiency via Singlet Fission

Singlet fission (SF) materials convert high-energy photons into multiple charge carriers, providing a route to exceed the efficiency limits of single-junction silicon solar cells without many of the complexities of multi-junction tandem designs. Following the first demonstration of an SF-enhanced silicon solar cell in 2025, there is a need to understand how SF materials can be effectively integrated into high-efficiency industrial silicon devices and translated from proof of concept to a manufacturable technology. Using coupled optical and electrical simulations, we assess the efficiency potential of several industrially relevant silicon cell architectures combined with SF materials. Interdigitated back-contact (IBC) cells offer the greatest potential for improvement due to unrestricted front-surface access and can achieve efficiencies exceeding 33%. However, performance is highly sensitive to front-surface passivation quality. Appropriate silicon design, particularly controlled surface doping and fixed interfacial charge, can mitigate recombination losses and relax passivation requirements for ultra-thin exciton-transfer layers.

cond-mat.mtrl-sci↗