Effect of annealing temperature on the optical properties of nanosilicon produced from silicon monoxide

Dorofeev, S. G.; Ischenko, A. A.; Kononov, N. N.; Fetisov, Gennady V.

doi:10.1016/j.cap.2011.10.016

Cited by 20 publications

(35 citation statements)

References 40 publications

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“…The stage I is the thermal annealing of the SiO powders at various temperatures T an from 350°C and up to 1100°C. The samples annealed at the stage I were marked as Si350 I , Si900 I , and Si1100 I , respectively (the number indicates the annealing temperature T an , and the upper index indicates that the samples were obtained after the stage I), and the not annealed SiO samples as Si25 (see also [20], which gives a fairly detailed description of the nanosilicon synthesis from SiO).…”

Section: Synthesis Of Silicon Nanoparticlesmentioning

confidence: 99%

“…To monitor the completeness of the SiO 2 removal, the XRD study of the samples was conducted, which showed the absence of silica after etching in hydrofluoric acid [20]. At the stage III, the procedure of thermally activated hydrosilylation of the nanosilicon particle surface (saturated with the Si-H fragments) was implied, as described in [19,20]. 1-Octadecene was used to obtain hydrophobic nanoparticles.…”

Section: Synthesis Of Silicon Nanoparticlesmentioning

confidence: 99%

“…We synthesize the core/shell Si/SiO x nanoparticles having an intense redinfrared photoluminescence by cost-effective and potentially scalable method of synthesis-thermal disproportionation of silicon monoxide in air at temperatures from 300 to 1350°C [8,19,20]. In the course of such synthesis, a microdispersed powder of silicon monoxide, having an average particle size of *100 nm, turns into a sol of Si/ SiO x -NP, possessing a stable, intense red-infrared photoluminescence.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis of photoluminescent Si/SiO x core/shell nanoparticles by thermal disproportionation of SiO: structural and spectral characterization

et al. 2014

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Core/shell Si/SiO x nanoparticles (Si/SiO x -NP) having bright red-infrared photoluminescence were obtained by a three-stage synthesis based on the thermal disproportionation of microdispersed SiO. Transformation patterns of structure and spectroscopic properties of the material during passage through all process stages (starting from initial SiO microparticles and up to the Si/SiO x -NP sols) have been revealed by using Raman, photoluminescence and ESR spectroscopy, XPS, XRD, and electron microscopy. Thermal annealing of SiO microparticles (stage I) results in formation of amorphous-crystalline Si nanophase in the matrix of SiO 2 , as well as generation of paramagnetic P b centres with the concentration up to 4 9 10 18 particles/g. At the annealing temperature, T an [ 900°C, a rapid growth of nanocrystal sizes takes place, and, simultaneously, a rapid growth of paramagnetic P b centre concentration occurs. Elimination of SiO 2 from the annealed sample by etching in HF (stage II) stimulates further crystallization of amorphous-crystalline core, caused by stress relaxation inside the Si core when removing SiO 2 matrix. Functionalization of nanoparticle surface (stage III) allows obtaining core/shell Si/SiO x -NP with a bright red-infrared photoluminescence and their sols. Average size of the crystalline Si core increases from 4.7 to 11.1 nm when T an at the stage I rises from 350 to 1100°C. At relatively low T an = 350°C, the nanoparticles with monocrystalline Si cores are mainly formed, while at T an [ 1100°C, a large number of polycrystalline Si nanoparticles are also observed. Our TEM images have revealed the existence of monocrystalline Si nanoparticles having significantly different contrast even at comparable nanoparticle sizes. We attribute that to the formation of both bulk (with a high TEM contrast) and flat (2D) Si nanocrystals (with a low TEM contrast) in the course of SiO annealing.

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Section: Synthesis Of Silicon Nanoparticlesmentioning

confidence: 99%

Section: Synthesis Of Silicon Nanoparticlesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Synthesis of photoluminescent Si/SiO x core/shell nanoparticles by thermal disproportionation of SiO: structural and spectral characterization

et al. 2014

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“…The commercial SiO powder precursor used by Liu 27 and Dorofeev 28 were claimed to be amorphous, 30 however, their powder X-ray diffraction (PXRD) results clearly show a crystalline silicon phase prior to any thermal treatment or at very low temperatures (200°C). It is conceivable in this earlier work that the size and yield of the resultant ncSi after thermal annealing would sensitively depend on the presence of the initial ncSi, which could act as nucleation sites as well as possibly influence the thermal disproportionation.…”

Section: Dependence Of Ncsi Formation On Thermal Treatment Temperaturementioning

confidence: 99%

“…27 Dorofeev et al expanded upon this work and reported a maximum PL QY of 12% for ncSi. 28 Recently we successfully synthesized ncSi from SiO at a specific heating temperature of 900°C, the size distribution of which enabled a study on the size dependence of the absolute quantum yield (AQY) on passing from bulk to quantum confined silicon. 29 However, much detailed information about the chemistry during such synthesis was left to be investigated.…”

Section: Introductionmentioning

confidence: 99%

Silicon monoxide – a convenient precursor for large scale synthesis of near infrared emitting monodisperse silicon nanocrystals

Sun

Qian

et al. 2016

Nanoscale

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While silicon nanocrystals (ncSi) embedded in silicon dioxide thin films have been intensively studied in physics, the potential of batch synthesis of silicon nanocrystals from the solid-state disproportionation of SiO powder has not drawn much attention in chemistry. Herein we describe some remarkable effects observed in the diffraction, microscopy and spectroscopy of SiO powder upon thermal processing in the temperature range 850-1100 °C. Quantum confinement effects and structural changes of the material related to the size of the silicon nanocrystals nucleated and grown in this way were established by Photoluminescence (PL), Raman, FTIR and UV-Visible spectroscopy, PXRD and STEM, pinpointing that the most significant disproportionation transformations happened in the temperature range between 900 and 950 °C. With this know-how a high yield synthesis was developed that produced polydispersions of decyl-capped, hexanesoluble silicon nanocrystals predominantly with near infrared (NIR) PL. Using size-selective precipitation, these polydispersions were separated into monodisperse fractions, which allowed their PL absolute quantum yield (AQY) to be studied as a function of silicon nanocrystal size. This investigation yielded volcano-shaped plots for the AQY confirming the most efficient PL wavelength for ncSi to be located at around 820-830 nm, which corresponded to a size of 3.5-4.0 nm. This work provides opportunities for applications of size-selected near infrared emitting silicon nanocrystals in biomedical imaging and photothermal therapy. While silicon nanocrystals (ncSi) embedded in silicon dioxide thin films have been intensively studied in physics, the potential of batch synthesis of silicon nanocrystals from the solid-state disproportionation of SiO powder has not drawn much attention in chemistry. Herein we describe some remarkable effects observed in the diffraction, microscopy and spectroscopy of SiO powder upon thermal processing in the temperature range 850-1100°C. Quantum confinement effects and structural changes of the material related to the size of the silicon nanocrystals nucleated and grown in this way were established by Photoluminescence (PL), Raman, FTIR and UV-Visible spectroscopy, PXRD and STEM, pinpointing that the most significant disproportionation transformations happened in the temperature range between 900 and 950°C. With this know-how a high yield synthesis was developed that produced polydispersions of decyl-capped, hexane-soluble silicon nanocrystals predominantly with near infrared (NIR) PL. Using sizeselective precipitation, these polydispersions were separated into monodisperse fractions, which allowed their PL absolute quantum yield (AQY) to be studied as a function of silicon nanocrystal size. This investigation yielded volcano-shaped plots for the AQY confirming the most efficient PL wavelength for ncSi to be located at around 820-830 nm, which corresponded to a size of 3.5-4.0 nm. This work provides opportunities for applications of size-selected near infrared emit...

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Insights into the Effect of Heat Treatment and Carbon Coating on the Electrochemical Behaviors of SiO Anodes for Li‐Ion Batteries

Hou

Wang

et al. 2022

Advanced Energy Materials

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The use of SiO as an anode material has attracted significant interest due to its high capacity and long cycling life. Many promising approaches, including structural design and carbon coating at high temperatures, effectively improve its intrinsic low electrical conductivity and poor Coulombic efficiency. However, the “heat treatment process‐composition and microstructure‐electrochemical properties” relationship of the SiO anode is not fundamentally understood. Here the structure and composition evolution in amorphous SiO and graphene‐coated SiO is investigated using different heat‐treatment conditions. X‐ray absorption near‐edge structure techniques are also employed to analyze the surface and bulk composition change during the initial lithiation process, supplemented by physical or chemical characterization and electrochemical testing. The results reveal the structural transition of SiO during heat treatment, from amorphous to disproportionated hierarchical structure, where the as‐formed dielectric exterior SiO2 shell and interior SiO2 matrix severely polarizes electrodes, hindering the lithiation process. Carbon coating on SiO effectively restricts the growth of the SiO2 shell and facilitates charge transfer, leading to improved electrochemical performance. A schematic model is proposed to reveal the relationship between the treatments, the resultant structural evolutions, and corresponding electrochemical behaviors.

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Effect of annealing temperature on the optical properties of nanosilicon produced from silicon monoxide

Cited by 20 publications

References 40 publications

Synthesis of photoluminescent Si/SiO x core/shell nanoparticles by thermal disproportionation of SiO: structural and spectral characterization

Synthesis of photoluminescent Si/SiO x core/shell nanoparticles by thermal disproportionation of SiO: structural and spectral characterization

Silicon monoxide – a convenient precursor for large scale synthesis of near infrared emitting monodisperse silicon nanocrystals

Insights into the Effect of Heat Treatment and Carbon Coating on the Electrochemical Behaviors of SiO Anodes for Li‐Ion Batteries

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