Room temperature oxidation of Si nanocrystals at dry and wet air

Popelensky, Vadim M.; Dorofeev, S. G.; Kononov, N. N.; Bubenov, Sergei S.; Vinokurov, A. A.

doi:10.1007/s11051-020-4762-4

Cited by 6 publications

(5 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The features we observe in the 2150–2300 cm –1 range correspond to Si–H stretching for silicon back-bonded to oxygen atoms, with O 2 SiH 2 at 2200 cm –1 and O 3 SiH at 2249 cm –1 . The emergence of these peaks after HWA indicates the development of a silica shell through the presence of water vapor and, in conjunction with the presence of the Si–O–Si peak, suggests the full formation of a silica shell while maintaining an intact Si core. ,,, …”

Section: Resultsmentioning

confidence: 73%

Photoluminescent Si/SiO₂ Core/Shell Quantum Dots Prepared by High-Pressure Water Vapor Annealing for Solar Concentrators, Light-Emitting Devices, and Bioimaging

Loh

Andaraarachchi

Ferry

et al. 2023

ACS Appl. Nano Mater.

View full text Add to dashboard Cite

As non-toxic, elementally abundant, and low-cost luminophores, silicon quantum dots (Si QDs) suit a wide variety of applications, from luminescent devices, such as solar concentrators and light-emitting diodes, to bioimaging. Nonthermal plasma-assisted decomposition of silane gas is an efficient, relatively sustainable, and controllable method for synthesizing Si QDs. However, as-synthesized Si QDs have a high defect density and require additional passivation for utilization in these settings. Liquid-based passivation methods, such as thermal hydrosilylation, organically cap Si QDs but cannot prevent oxidation upon exposure to ambient air. Native oxidation effectively passivates the Si QDs and ensures long-term stability in air but typically requires long exposures to ambient conditions. Here, we report the use of high-pressure water vapor annealing (HWA) to quickly obtain Si/SiO2 core/shell quantum dots with tunable photoluminescence (PL). We first show that the injection of additional hydrogen gas, commonly used in synthesizing organically capped Si QDs, is detrimental to achieving stable silica shells. Then, we demonstrate that varying the applied pressure tunes the PL quantum yield. At higher pressures, the formed silica shells are fully thermally relaxed. Lastly, we report the influence of silica shell thickness, with thicker silica shells leading to environmentally stable quantum yields of >40%. Compared to both thermal hydrosilylation and native oxidation, HWA is a convenient and rapid technique for surface passivation.

show abstract

Section: Resultsmentioning

confidence: 73%

Photoluminescent Si/SiO₂ Core/Shell Quantum Dots Prepared by High-Pressure Water Vapor Annealing for Solar Concentrators, Light-Emitting Devices, and Bioimaging

Loh

Andaraarachchi

Ferry

et al. 2023

ACS Appl. Nano Mater.

View full text Add to dashboard Cite

show abstract

“…It is interesting to note that the absorption band at 2250 cm À1 is broad compared to that of TES, with a shoulder at 2344 cm À1 , which is attributed to the stretching of the oxidized Si H groups (O 3 Si H). 23 Absorption bands corresponding to the alkyl groups are absent in SQVH-12, suggesting the complete hydrolysis and condensation of the ethoxy groups in TES and VTEOS. Solid state 29 Si-NMR spectrum of SQVH-12 is shown in Figure 3a.…”

Section: Resultsmentioning

confidence: 98%

“…FTIR spectrum of VTEOS in Figure 2a shows the characteristic absorption bands of vinyl group at 1411 and 1600 cm −1 , whereas the FTIR spectrum of TES (Figure 2b) shows the characteristic absorption bands of SiH group at 2200 and 869 cm −1 . It is interesting to note that the absorption band at 2250 cm −1 is broad compared to that of TES, with a shoulder at 2344 cm −1 , which is attributed to the stretching of the oxidized SiH groups (O 3 SiH) 23 . Absorption bands corresponding to the alkyl groups are absent in SQVH‐12, suggesting the complete hydrolysis and condensation of the ethoxy groups in TES and VTEOS.…”

Section: Resultsmentioning

confidence: 99%

Vinylhydridosilsesquioxne: Synthesis and characterization of a potential filler material for vinyl‐containing polysiloxanes

Yesudas,

Sreejith,

Vijay

2023

J of Applied Polymer Sci

View full text Add to dashboard Cite

This paper reports the synthesis and characterization of an organic silsesquioxane (SQ) containing Sivinyl and SiH groups named as vinylhydridosilsesquioxane (SQVH‐12). Detailed investigation of the structure of this organosilsesquioxane revealed that SQVH‐12 has a highly cross‐linked (polycyclic) SiO network of silsesquioxane with Sivinyl and SiH functional groups. Thermogravimetric analysis of the pyrolysis behavior of SQVH‐12 yielded a high percentage of ceramic residue (~92%) at 1200°C under an argon atmosphere. The presence of functional groups in SQVH‐12 and the high rate of ceramic residue highlights the potential usefulness of SQVH‐12 as a filler for vinyl‐containing polysiloxanes. Thus, further research of SQVH‐12 can find applications in a wide variety of areas such as additive manufacturing, protective coatings, and advanced composites.

show abstract

“…All in all, we are driven to the conclusion that FEEPS is the dominant mechanism for the tribochemical wear of silica and by extension silicon since a silicon surface is always covered by a silica oxide layer in humid environments. [ 60 ]…”

Section: Resultsmentioning

confidence: 99%

A New Method of AFM‐Based Nanolithography Using Frequency Enhanced Electrochemical Pressure Solution Etching

Fraysse

MacLeod

Gates

et al. 2023

Adv Materials Technologies

View full text Add to dashboard Cite

A new method of direct‐write nanolithography that is able to rapidly etch silica surfaces under a scanning atomic force microscopy (AFM) probe in tapping mode (TM) is reported. In this lithography technique, silica surfaces are etched using a recently described electro‐chemo‐mechanical phenomenon of frequency enhanced electrochemical pressure solution (FEEPS). In FEEPS, the tapping of the AFM tip generates oscillations of the Stern potential at the silica‐water interface that can accelerate the silica dissolution kinetics by more than 5–6 orders of magnitude when surface resonance states are achieved; i.e., when the oscillation frequency is in phase with the dynamics of interfacial chemical reaction steps. By scanning silica surfaces in TM, silica is selectively dissolved below the tapping tip as it is scanned. The FEEPS accelerated silica dissolution rates can generate etched features with depths of more than 60 nm in a single AFM tip pass. The rate of etching can be controlled easily by varying the scanning rate or by modulating the tapping frequency. This fine control over the silica etching process and because material is removed (dissolved) rather than displaced as with nanoscratching, the FEEPS process lends itself to gray‐scale nanolithography which is demonstrated.

show abstract

Room temperature oxidation of Si nanocrystals at dry and wet air

Cited by 6 publications

References 28 publications

Photoluminescent Si/SiO₂ Core/Shell Quantum Dots Prepared by High-Pressure Water Vapor Annealing for Solar Concentrators, Light-Emitting Devices, and Bioimaging

Photoluminescent Si/SiO₂ Core/Shell Quantum Dots Prepared by High-Pressure Water Vapor Annealing for Solar Concentrators, Light-Emitting Devices, and Bioimaging

Vinylhydridosilsesquioxne: Synthesis and characterization of a potential filler material for vinyl‐containing polysiloxanes

A New Method of AFM‐Based Nanolithography Using Frequency Enhanced Electrochemical Pressure Solution Etching

Contact Info

Product

Resources

About

Room temperature oxidation of Si nanocrystals at dry and wet air

Cited by 6 publications

References 28 publications

Photoluminescent Si/SiO2 Core/Shell Quantum Dots Prepared by High-Pressure Water Vapor Annealing for Solar Concentrators, Light-Emitting Devices, and Bioimaging

Photoluminescent Si/SiO2 Core/Shell Quantum Dots Prepared by High-Pressure Water Vapor Annealing for Solar Concentrators, Light-Emitting Devices, and Bioimaging

Vinylhydridosilsesquioxne: Synthesis and characterization of a potential filler material for vinyl‐containing polysiloxanes

A New Method of AFM‐Based Nanolithography Using Frequency Enhanced Electrochemical Pressure Solution Etching

Contact Info

Product

Resources

About

Photoluminescent Si/SiO₂ Core/Shell Quantum Dots Prepared by High-Pressure Water Vapor Annealing for Solar Concentrators, Light-Emitting Devices, and Bioimaging

Photoluminescent Si/SiO₂ Core/Shell Quantum Dots Prepared by High-Pressure Water Vapor Annealing for Solar Concentrators, Light-Emitting Devices, and Bioimaging