Freestanding silicon nanocrystals with extremely low defect content

Pereira, Rui N.; Rowe, David J.; Anthony, Rebecca; Kortshagen, Uwe R.

doi:10.1103/physrevb.86.085449

Cited by 22 publications

(36 citation statements)

References 45 publications

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“…Namely those on Si QDs in the nanocomposite constituted only 73% of the ones in the toluene solution, as can be deduced from the EPR signal amplitudes for the T/E ratio of 2/1. Although the EPR can detect only specific kinds of paramagnetic defects, [ 24 ] the decrease in the signal strongly suggests that QD surface dangling bonds combined with matrix radicals to form stable covalent bonds during the polymerization process. As a result, some dark particles were turned into bright ones, [21b] as shown in Figure 1A, and thereby, the total PLQY of the composite was enhanced.…”

Section: Resultsmentioning

confidence: 99%

Triplex Glass Laminates with Silicon Quantum Dots for Luminescent Solar Concentrators

et al. 2020

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Luminescent solar concentrator (LSC) is a promising technology to integrate semitransparent photovoltaic (PV) systems into modern buildings and vehicles. Silicon quantum dots (QDs) are good candidates as fluorophores in LSCs, due to the absence of overlap between absorption and emission spectra, high photoluminescence quantum yield (PLQY), good stability, nontoxicity, and element abundance. Herein, LSCs based on Si QDs/polymer nanocomposites are fabricated in a triplex glass configuration. A special polymer matrix (off‐stoichiometric thiol‐ene, OSTE) is used, which improves Si nanocrystal quantum yield. Herein, a comprehensive investigation to improve the performance of LSCs by exploring different strategies under the guidance of a theoretical description is conducted. Among these strategies, the systematical enhancement of PLQY of the nanocomposite is achieved by tuning the thiol/allyl group ratio in the OSTE matrix. In addition, ligand selection and loading optimization for QDs reduce the total scattering loss in the device. Finally, an optical power efficiency of 7.9% is achieved for an optimized LSC prototype (9 × 9 × 0.6 cm3, transmittance ≈62% at 500 nm) based on Si QDs/OSTE nanocomposite, which shows good potential of this material system in LSC fabrication.

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Section: Resultsmentioning

confidence: 99%

Triplex Glass Laminates with Silicon Quantum Dots for Luminescent Solar Concentrators

et al. 2020

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“…The SiNPs were synthesized by the decomposition of silane gas using a nonthermal plasma and were functionalized with 1‐dodecene, as detailed in the Experimental Section. In order to evaluate the SiNPs‐C12 mean size, the samples were characterized by X‐ray diffraction, whose pattern ( Figure ) reveals reflections near 32.8°, 55.3°, and 66.1°, corresponding to (111), (220), and (311) silicon crystal planes, respectively .…”

Section: Resultsmentioning

confidence: 99%

“…The pressure in the reactor was kept constant at ≈1.4–1.5 Torr by using an electronically controlled throttle valve. Hydrogen gas was injected into the plasma afterglow at a flow rate of 100 sccm to reduce surface dangling bond defects . After growth, the hydrogen terminated SiNPs were functionalized with 1‐dodecene (Si‐NPs‐C12) under air‐free conditions in a thermal hydrosilylation reaction .…”

Section: Methodsmentioning

confidence: 99%

A New Generation of Primary Luminescent Thermometers Based on Silicon Nanoparticles and Operating in Different Media

Botas

Brites

et al. 2016

Part & Part Syst Charact

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Luminescence nanothermometry is nowadays a highly‐dynamic research topic that is being driven by the challenging demands arising from dissimilar areas such as microelectronics, microfluidics and nanomedicine. Although the technique is rapidly evolving from the initial breakthrough to real applications, there are still major challenges regarding the conciliation of nanometric probes with the high sensitivity and predictability of the thermal response of the system. In the past five years, luminescent thermometers operating at the nanoscale, where the conventional methods are ineffective, have emerged as a very active field of research. Luminescent silicon nanoparticles (SiNPs) are a promising choice for nanothermometry, combining the Si biocompatibility with the compatibility with the current microelectronic technology. Here, the thermal dependence of the emission peak position of SiNPs, used as the thermometric parameter, is well‐described by the Varshni's law, enabling the development of a self‐calibrated nanothermometer with a calibration curve predicted by a well‐stablished state equation, avoiding new calibration procedures whenever the thermometer operates in different media. For the first time, temperature sensing using SiNPs‐based luminescent thermometers in different media without the need of new calibration procedures is demonstrated. The thermometer reveals reversibility and repeatability higher than 99.98%, and a maximum relative sensitivity of 0.04% K−1.

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“…4 Our results indicate that in a given sample, the number of NPs exhibiting exponential type blinking varies with size, strain and surface passivation. Hydrogen treatment [68][69][70] and annealing [70][71][72] may help reduce the density of dangling bonds possibly reducing the amount of blinking. Deep level transient spectroscopy could be used to quantify the effects of strain by measuring charge transition levels and electron spin resonance experiments would be a good additional probe to validate our predictions.…”

Section: Discussionmentioning

confidence: 99%

Surface dangling bonds are a cause of B-type blinking in Si nanoparticles

2015

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Exponential blinking statistics was reported in oxidized Si nanoparticles and the switching mechanism was attributed to the activation and deactivation of unidentified nonradiative recombination centers. Using ab initio calculations we predicted that Si dangling bonds at the surface of oxidized nanoparticles introduce defect states which, depending on their charge and local stress conditions, may give rise to ON and OFF states responsible for exponential blinking statistics. Our results are based on first principles calculations of charge transition levels, single particle energies, and radiative and nonradiative lifetimes of dangling bond defects at the surface of oxidized silicon nanoparticles under stress.

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Freestanding silicon nanocrystals with extremely low defect content

Cited by 22 publications

References 45 publications

Triplex Glass Laminates with Silicon Quantum Dots for Luminescent Solar Concentrators

Triplex Glass Laminates with Silicon Quantum Dots for Luminescent Solar Concentrators

A New Generation of Primary Luminescent Thermometers Based on Silicon Nanoparticles and Operating in Different Media

Surface dangling bonds are a cause of B-type blinking in Si nanoparticles

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