Size-Dependent Photoluminescence Efficiency of Silicon Nanocrystal Quantum Dots

Yu, Yixuan; Fan, Gang; Fermi, Andrea; Mazzaro, Raffaello; Morandi, Vittorio; Ceroni, Paola; Smilgies, Detlef‐M.; Korgel, Brian A.

doi:10.1021/acs.jpcc.7b08054

Cited by 105 publications

(143 citation statements)

References 56 publications

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“…In general, the mean decay time was longer for larger particles, which is knownf rom the literature and attributed to the loss of confinement with increasing diameter. [39,40] In addition, the effect of temperatureo nt he decay dynamics was more pronounced for ensembles with a smaller average particled iameter,w hich is also consistent with previousr eports. [24,41] This behavior could be caused by the increasedo xidation of the smaller particles.…”

Section: Low-temperature Pl and Time-resolved Spectroscopysupporting

confidence: 88%

Ensemble Effects in the Temperature‐Dependent Photoluminescence of Silicon Nanocrystals

Jakob

Javadi

Veinot

et al. 2019

Chemistry A European J

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In this work the temperature-dependent photoluminescence of alkyl-capped silicon nanocrystals with mean diameters of between 3a nd 9nmh as been investigated. The nanocrystals were characterizede xtensively by FTIR, TEM, powder XRD, and X-ray photoelectron spectroscopy prior to low-temperature and time-resolved photoluminescence spectroscopy experiments. The photoluminescence (PL) properties were evaluated in the temperature range of 41-300 K. We found that the well-known temperature-de-pendentb lueshift of the PL maximum decreases with increasingn anocrystal diameter and eventually becomes a redshift for nanocrystal diameters larger than 6nm. This implies that the observed shiftsc annotb ee xplained solely by band-gap widening, as is commonlya ssumed. We propose that the luminescence of drop-cast silicon nanocrystals is affectedby particlee nsemble effects,w hich can explain the otherwise surprising temperature dependence of the luminescencepeak.[a] M.Supporting information and the ORCID identification number(s) for the author(s) of this articlecan be found under: https://doi.

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Section: Low-temperature Pl and Time-resolved Spectroscopysupporting

confidence: 88%

Ensemble Effects in the Temperature‐Dependent Photoluminescence of Silicon Nanocrystals

Jakob

Javadi

Veinot

et al. 2019

Chemistry A European J

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“…Notably, the PL lifetime at a given emission wavelength remained nearly constant during dissolution (Figure f). Because the emission wavelength is characteristic of size of the quantum‐confined domains in the silicon skeleton of the nanoparticle, this result indicates that, for a given nanocrystallite size, the dissolution process did not introduce additional nonradiative electron–hole recombination sites—in other words, the emission quantum yield was more dependent on the size of the silicon domains in the nanoparticle than on the length of time it had been exposed to the dissolution conditions.…”

Section: Methodsmentioning

confidence: 98%

Tracking the Fate of Porous Silicon Nanoparticles Delivering a Peptide Payload by Intrinsic Photoluminescence Lifetime

et al. 2018

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A nanoparticle system for systemic delivery of therapeutics is described, which incorporates a means of tracking the fate of the nanocarrier and its residual drug payload in vivo by photoluminescence (PL). Porous silicon nanoparticles (PSiNPs) containing the proapoptotic antimicrobial peptide payload, [KLAKLAK] , are monitored by measurement of the intrinsic PL intensity and the PL lifetime of the nanoparticles. The PL lifetime of the PSiNPs is on the order of microseconds, substantially longer than the nanosecond lifetimes typically exhibited by conventional fluorescent tags or by autofluorescence from cells and tissues; thus, emission from the nanoparticles is readily discerned in the time-resolved PL spectrum. It is found that the luminescence lifetime of the PSiNP host decreases as the nanoparticle dissolves in phosphate-buffered saline solution (37 °C), and this correlates with the extent of release of the peptide payload. The time-resolved PL measurement allows tracking of the in vivo fate of PSiNPs injected (via tail vein) into mice. Clearance of the nanoparticles through the liver, kidneys, and lungs of the animals is observed. The luminescence lifetime of the PSiNPs decreases with increasing residence time in the mice, providing a measure of half-life for degradation of the drug nanocarriers.

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“…What can be seen from Figure a is that after replacement of dodecene with hexane, the peak 1 disappears and the normalized QY dispersion seems to resemble the one reported by Mastronardi et al where NCs were functionalized with allylbenzene. The QY optimum in data presented by Yu et al is located at the peak 2 albeit NCs were functionalized with dodecene. From Figure a, one may conclude that positions of peaks are not related to surface functionalization.…”

Section: Resultsmentioning

confidence: 94%

“…However, the reported results in the literature are scarce and very few points in PL properties of Si NCs can be found in common. Thus, it is known that PL of small NCs emitting in the visible region is faster and generally less efficient (ultimately reaching zero efficiency near the F‐band) in comparison with Si NCs emitting in the NIR region. Although the faster decay is expected, the lower QY is in dissonance with the QC model where the probability of radiative relaxation (oscillator strength) should increase with shrinking size.…”

Section: Resultsmentioning

confidence: 99%

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Spectral Dependencies of the Stretched Exponential Dispersion Factor and Photoluminescence Quantum Yield as a Common Feature of Nanocrystalline Si

Greben

Khoroshyy

Valenta

2019

Physica Status Solidi (a)

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Herein, the spectral dependencies of the dispersion factor β (from the stretched exponential function) and photoluminescence (PL) quantum yield (QY) of silicon nanocrystals (Si NCs) are thoroughly studied. Spectrally resolved PL decay kinetics of Si NCs in both liquid and solid samples are measured and their corresponding distributions of rates are retrieved by means of the hybrid maximum‐entropy method. This enables us to demonstrate a direct correlation of dispersion factor β with the width of rate distribution. Here, the evidence of the same step‐like spectral dependence of rate distribution widths (dispersion factor) for different forms of nanocrystalline silicon (including porous silicon and chemically synthesized Si NCs) is presented suggesting intrinsic (core‐related) origin of rate distributions. Spectral dependence of normalized QY of Si NCs reveals two characteristic peaks with spectral positions at ≈1.42 and ≈1.68 eV. A similar peak in QY spectral dependence of CdSe quantum dots (QDs) is found, which suggests its common origin regardless the material of semiconductor QDs.

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Size-Dependent Photoluminescence Efficiency of Silicon Nanocrystal Quantum Dots

Cited by 105 publications

References 56 publications

Ensemble Effects in the Temperature‐Dependent Photoluminescence of Silicon Nanocrystals

Ensemble Effects in the Temperature‐Dependent Photoluminescence of Silicon Nanocrystals

Tracking the Fate of Porous Silicon Nanoparticles Delivering a Peptide Payload by Intrinsic Photoluminescence Lifetime

Spectral Dependencies of the Stretched Exponential Dispersion Factor and Photoluminescence Quantum Yield as a Common Feature of Nanocrystalline Si

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