Routes to Achieving High Quantum Yield Luminescence from Gas‐Phase‐Produced Silicon Nanocrystals

Anthony, Rebecca; Rowe, David J.; Stein, Matthias; Yang, Jun; Kortshagen, Uwe R.

doi:10.1002/adfm.201100784

Cited by 81 publications

(114 citation statements)

References 26 publications

(25 reference statements)

Supporting

Mentioning

110

Contrasting

Order By: Relevance

“…The reactor is a Pyrex tube through which silane diluted with a carrier gas is decomposed to form Si-NCs. A detailed description for the synthesis of the LIDD Si-NCs has been reported earlier, 27 so only the important features will be covered here. To prepare the LIDD Si-NCs, hydrogen gas was injected into the afterglow of the plasma and additional synthesis conditions are outlined in Table I.…”

Section: Methodsmentioning

confidence: 99%

Freestanding silicon nanocrystals with extremely low defect content

et al. 2012

View full text Add to dashboard Cite

The future exploitation of the exceptional properties of freestanding silicon nanocrystals (Si-NCs) in marketable applications relies upon our ability to produce large amounts of defect-free Si-NCs by means of a low-cost method. Here, we demonstrate that Si-NCs fabricated by scalable RF plasmaassisted decomposition of silane with additional hydrogen gas injected into the afterglow region of the plasma exhibit immediately after synthesis the lowest reported defect density, corresponding to a value of only about 0.002-0.005 defects per NC for Si-NCs with 4 nm in size. In addition, the virtually perfect hydrogen termination of these Si-NCs yields an enhanced resistance against natural oxidation in comparison to Si-NCs with nearly one order of magnitude larger initial defect density.

show abstract

Section: Methodsmentioning

confidence: 99%

Freestanding silicon nanocrystals with extremely low defect content

et al. 2012

View full text Add to dashboard Cite

show abstract

“…4,5 Also improvements in luminescent quantum yield of ncSi through surface-capping control, [6][7][8] makes them interesting for quantum dot applications. The synthetic strategies for making ncSi have been recently summarized by Mangolini.…”

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

View full text Add to dashboard Cite

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...

show abstract

“…It is well known that surface quality of nanostructures has a significant influence on related device performance. Several pioneer works on Si NC-based device have shown that the performance can be further improved through proper Si NCs surface treatment [35][36][37][38]. In this work, we demonstrate that controlled particle oxidization can be employed as an easy and effective way for surface passivation.…”

Section: Introductionmentioning

confidence: 88%