Size Dependence of the Melting Point of Silicon Nanoparticles: Molecular Dynamics and Thermodynamic Simulation

Talyzin, I. V.; Samsonov, M. V.; Samsonov, V. M.; Pushkar, M. Yu.; Dronnikov, V. V.

doi:10.1134/s1063782619070236

Cited by 21 publications

(15 citation statements)

References 23 publications

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“…This is more appropriately treated in the so-called surface-phonon instability model, 54 accounting for the lowering energy of the phonon modes with increasing concentration of defects, offering a better fit to the experimentally observed data. 55 , 56 These observations indicate that melting of the disordered surfaces occurs at lower temperatures compared to the melting of the crystalline core, in agreement with the aforementioned study by Talyzin et al 51 This could rationalize the formation of a crystalline core–amorphous shell Si-NP system.…”

Section: Resultssupporting

confidence: 89%

“…Another recent experimental study by Alessi et al 50 on plasma-synthesized Si-NPs suggested that the crystallinity of the Si-NP of the same size can be manipulated by changing the concentration of silane, which changes optical and electronic properties of the material. More importantly, a recent theoretical study by Talyzin et al 51 suggests that molten Si nanodroplets do not return to the crystalline form but remain fully amorphous and that Si-NP surface has a melting temperature different from that of its core. The phase-equilibrium model of crystallization indicates that the melting temperature of NPs decreases relative to the bulk melting temperature (∼1414 °C for Si) linearly with their reciprocal radius T m ( R –1 ), 52 , 53 though this model does not work very well for covalent materials like Si, where formation of defects (and hence also surfaces) has dynamics different from that in the simpler ionic/metallic nanosystems.…”

Section: Resultsmentioning

confidence: 99%

“…This is in agreement with our observations and two other studies by Thiessen et al 16 , 17 In fact, most studies in the literature do not exceed annealing over 1300 °C and do not pay special attention to the requirements of very slow cooling rates. 51 This could mean that many materials earlier presented as crystalline Si-NPs might have been partially or fully amorphous, where the relatively thin amorphous Si shell would have been difficult to identify via XRD, Raman spectroscopy, or other means. Second, another study on a similar material by Thiessen et al 17 arrived at an opposite interpretation that the PL is dominated by the crystalline Si core.…”

Section: Discussionmentioning

confidence: 99%

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Band-Gap Tunability in Partially Amorphous Silicon Nanoparticles Using Single-Dot Correlative Microscopy

Huang

Tang

Laan

et al. 2020

ACS Appl. Nano Mater.

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Silicon nanoparticles (Si-NPs) represent one of many types of nanomaterials, where the origin of emission is difficult to assess due to a complex interplay between the core and surface chemistry. Band-gap tunability in Si-NPs is predicted to span from the infrared to the ultraviolet spectral range, which is rarely observed in practice. In this work, we directly assess the size dependence of the optical band gap using a single-dot correlative microscopy tool, where the size of the individual NPs is measured using atomic force microscopy (AFM) and the optical band gap is evaluated from single-dot photoluminescence measured on the very same NPs. We analyze 2–8 nm alkyl-capped Si-NPs prepared by a sol–gel method, followed by annealing at 1300 °C. Surprisingly, we find that the optical band gap is given by the amorphous shell, as evidenced by the convergence of the optical band gap size dependence toward the amorphous Si band gap of ∼1.56 eV. We propose that the structural disorder might be the reason behind the often reported limited emission tunability from various Si-NPs in the literature. We believe that our message points toward a pressing need for development and broader use of such direct correlative single-dot microscopy methods to avoid possible misinterpretations that could arise from attempts to recover size–band gap relation from ensemble methods, as practiced nowadays.

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Section: Resultssupporting

confidence: 89%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Band-Gap Tunability in Partially Amorphous Silicon Nanoparticles Using Single-Dot Correlative Microscopy

Huang

Tang

Laan

et al. 2020

ACS Appl. Nano Mater.

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“…However, nanosized primary Si particles in a micrometer-sized Si particle are easily activated at high temperature because of lattice vibration at the surface and are fused together to form lager particles. [29,30] As a result, nanopores within micrometer-sized porous Si particles (Figure 1) will shrink, and the micrometer-sized particles will lose their porous structure as shown in Figure 1a, thus defeating the purpose of forming Si nanostructures in the material design. Therefore, we developed a pitch impregnation method to protect the nanostructure from damage during fabrication of micrometer-sized Si particles with desired nanostructure.…”

Section: Resultsmentioning

confidence: 99%

A Micrometer‐Sized Silicon/Carbon Composite Anode Synthesized by Impregnation of Petroleum Pitch in Nanoporous Silicon

Chae

et al. 2021

Advanced Materials

141

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the energy density of LIBs because Si has ten times higher theoretical capacity (3579 mAh g −1 ) comparing with those of conventional graphite (372 mAh g −1 ). [9][10][11] However, large-scale applications of Si anodes still face several significant challenges, including pulverization of Si particles, continuous growth of a solid electrolyte interface (SEI) layer during the charge/discharge processes, and large swelling of the Si-based anode. [12,13] Without successfully overcoming those challenges, Si can be used only as a limited additive in graphite-based anodes to incrementally increase the energy density of LIBs.Several approaches have been developed in recent years to address those challenges. [14][15][16][17] In this regard, Si nanocomposites stabilized by heterogeneous elements has been used as one of most effective approaches to accommodate large volume changes and prevent side reactions between the electrolyte and Si. [15,16,[18][19][20] Moreover, practical issues associated with the use of nanoengineered Si anodes [21] (e.g., high surface area, low density, and high interparticle resistance) have been addressed by building the nanostructure in a local scale within micrometersized particles. [14,[22][23][24] Representative design of nanostructured Si includes the pomegranate-inspired Si/C anode [23] and Si nanolayer embedded graphite. [24] These nanostructure materials form micrometer (µm) size particles that can be used in practical applications and that are compatible with conventional battery manufacturing process. However, as the primary particle size decreases to nanometer-scale, it is increasingly difficult to assemble nanostructured Si into micrometer-sized material. [25][26][27][28] In this work, we demonstrate a facile method for preparing a Si/C composite containing micrometer-sized nanoporous Si (denoted Np-Si) that is protected by pitch-derived carbon (denoted PC). The resulting PC/Np-Si not only successfully retains its single nanometer-sized Si primary particle without sintering in micrometer-scale, but also exhibits favorable powder properties for conventional battery manufacturing process such as narrow particle size distribution, high density, strong mechanical strength, and small surface area. It also exhibits low swelling upon lithiation at both particle-and Porous silicon (Si)/carbon nanocomposites have been extensively explored as a promising anode material for high-energy lithium (Li)-ion batteries (LIBs). However, shrinking of the pores and sintering of Si in the nanoporous structure during fabrication often diminishes the full benefits of nanoporous Si. Herein, a scalable method is reported to preserve the porous Si nano structure by impregnating petroleum pitch inside of porous Si before high-temperature treatment. The resulting micrometer-sized Si/C composite maintains a desired porosity to accommodate large volume change and high conductivity to facilitate charge transfer. It also forms a stable surface coating that limits the penetration of electrolyte into nanoporous Si and ...

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“…Er 3+ /Yb 3+ CaF 2 (PL ratio) [145] 0.015 293-318 Tm 3+ /Yb 3+ CaF 2 (PL ratio) [145] 0.002 293-318 NaYF 4 :Er 3+ , Yb 3+ (PL ratio) [146] 0.0114 298-334 NaLuF 4 :Yb, Er [147] 0.009 273-348 ZnO:Er 3+ (PL ratio) [148] 0.0098 278-463 β-NaYF 4 :20%Yb 2 %Er (PL ratio) [149] 0.0157 294-334 (Gd,Yb,Er) 2 O 3 (PL ratio) [32] 0.017 300-1050 Nanodiamonds (NDs) NV (PL intensity) [150] 0.01 295-400 GeV (ZPL linewidth) [151] 0.0064 150-400 SiV (ZPL shift) [152] 1.61 ×10 −5 285-305 SnV (ZPL shift) [153] 8.66 ×10 −5 295-315 GeV (anti-Stokes) [154] 0.014 150-400 Optically resonant nanoparticles (RNPs) Au nanorod (anti-Stokes PL) [34] 10 −3 300-1300 [155] Si (Stokes Raman shift) [55] 2×10 −4 0-1685 [156,157,158] α-Fe 2 O 3 (Stokes Raman shift) [159] 4×10 −4 0-1840 [160] Table 1: Nanothermometers. List of materials and nanothermometry techniques based on light-emitting materials, nanostructures, and nanomaterials.…”

Section: Basic Properties Of Materials Employed For Thermonanophotonicsmentioning

confidence: 99%

All-dielectric thermonanophotonics

Zograf,

Petrov,

Makarov

et al. 2021

Preprint

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Nanophotonics is an important branch of modern optics dealing with lightmatter interaction at the nanoscale. Nanoparticles can exhibit enhanced light absorption under illumination by light, and they become nanoscale sources of heat that can be precisely controlled and manipulated. For metal nanoparticles, such effects have been studied in the framework of thermoplasmonics which, similar to plasmonics itself, has a number of limitations. Recently emerged all-dielectric resonant nanophotonics is associated with optically-induced electric and magnetic Mie resonances, and this field is developing very rapidly in the last decade. As a result, thermoplasmonics is being replaced by all-dielectric thermonanophotonics with many important applications such as photothermal cancer therapy, drug and gene delivery, nanochemistry, and photothermal imaging. This review paper aims to introduce this new field of non-plasmonic nanophotonics and discuss associated thermally-induced processes at the nanoscale.

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Size Dependence of the Melting Point of Silicon Nanoparticles: Molecular Dynamics and Thermodynamic Simulation

Cited by 21 publications

References 23 publications

Band-Gap Tunability in Partially Amorphous Silicon Nanoparticles Using Single-Dot Correlative Microscopy

Band-Gap Tunability in Partially Amorphous Silicon Nanoparticles Using Single-Dot Correlative Microscopy

A Micrometer‐Sized Silicon/Carbon Composite Anode Synthesized by Impregnation of Petroleum Pitch in Nanoporous Silicon

All-dielectric thermonanophotonics

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